[FTC]: Samantha? Like it or hate it?
 

I knew from the start that I wasn't going to be fond of the new samantha module and fcs setup, especially after today's events at the Clarkson Regional, however this is not an attack on those that run the regional it is a new system and things like this can happen and I hope we can come to the root of why here.

My initial thoughts were with the comparison to FRC I feel like while using new technology to pilot the robots does open up more possibilities it will also allow for more problems. Right now I feel like many of the problems of the new samantha module come from interference, as well as the fact that it is brand new this year. For instance it seems like now every new gadget has wifi capabilities and if every cell phone and ipod that's in the arena is putting out a wifi signal then there will be a compounding rate of interference with the wifi used to communicate with the field. I liked bluetooth because it seemed like whenever a problem occured it was my fault not someone else and that meant I could correct the problem the next time we went out for a match. Also while many things do use bluetooth the limited range means someone on the other side of the arena won't be interferring with your connection and there is a smaller number of such devices being used.

If anyone sees something wrong with what I said above please correct me and if anyone that was at Clarkson today has any more insight on the problems that occured I would love to here what happened. Please feel free to post about any problems you see with the samantha and possible fixes to these. We're engineers and we're here to fix problems, please don't post here trying to attack or blame anyone else that isn't going to solve anything, plus while some field techs may make mistakes sometimes we would too if we had their job.

Re: [FTC]: Samantha? Like it or hate it?
 

Wellll...

You said a lot, but didn't really say anything specifc.

Exactly what were the problems that you saw at the regional?

Maybe someone has seen them before....
Maybe you can prevent them from occuring again.

Just staying there were problems, but that's normal .... wasn't particularly helpfull or engineering-like. More like most news reports these days...

Try this approach next time........

-----------------------------------------------
We saw several problems at the xxx regional.
a) xxx happened whenever yyy occured
b) some people had zzz happen to them...

The problems seemed to be Samantha based.
I say this for the following reasons:
a) reason 1
b) reason 2
c) some other mitigating factor....
Has anyone seen simmilar occurances?
Could there be another reason for the observed events?
---------------------------------------------------

That's more the way an Engineer or Scientist is meant to think.

Phil.

Re: [FTC]: Samantha? Like it or hate it?
 

I was also at the regional - It's hard to be specific about the problem because there wasn't any communication about them - an announcement about technical difficulties, followed by "We'll be back in half an hour", then two hours later, Alliance selection. Each team had only 2 rounds of play, except the first place team (which had 3 matches) and the last place team (which had 1).

It's worth noting that the communication breakdown wasn't only between the event staff and the teams - I spoke to many event people trying to figure out what was going on, and noone knew anything.

This also screwed up alliance selection - how do you pick alliances when you haven't seen everyone play? Additionally, they redid stats halfway through, so two teams who hadn't seen the updated lists had to pick without time to think about who they would pick.

Overall, though, other than the communication, Clarkson regional did do an excellent job of finishing the event, given the technical problems. Worth noting, there was a lot of testing of the equipment the night before, with no problems.

It's reminiscent of FRC with all the wireless issues with the new system.

In terms of the actual issues, sometimes communication would simply stop between the robots and the FMS, sometimes there were delays of up to five seconds, sometimes the Samantha modules wouldn't connect. Without communication, though, there wasn't a lot of seeing the what caused it.

Re: [FTC]: Samantha? Like it or hate it?
 

The actual hardware of the Samantha's seems to be flawed - or at least the configuration system. Two of my team's sister teams had their Samantha's stop functioning after the inspection judge "downloaded" the new configuration onto them.
Also, at the St. Louis regional, there were many problems with disconnections of the Samantha. The problems were persistent throughout the competition and the referees decided to allow some robots to disconnect because "there was no considerable change to the outcome of the match". There was only one match that was replayed. Interestingly, that match had a relatively minor disconnect (the Samantha reconnected after a few seconds, while in other matches the Samantha would stay disconnected the entire time or would continuously disconnect and reconnect to the point where the robot was unusable) and was also a blowout (one alliance had a massively larger amount of points than the other).
The problems continued into the Finals, where 2 out of 3 matches had disconnected during both autonomous (stopping the autonomous program executions) and in teleop.

Bluetooth had some major flaws, but it still seemed much more consistent (at least once it finally connected to the system) than the Wifi with the samantha did.

Re: [FTC]: Samantha? Like it or hate it?
 

Any possibility that the issues were related to the following experience and solution posted in this thread?

Re: [FTC]: Samantha? Like it or hate it?
 

I'm sorry to hear about the problems in New York and St. Louis. I was the FTA for the Kell Robotics FTC Qualifier in Georgia and we saw none of those problems. This was the first qualifier for our state and so we had to flash each of the Samanthas with the configuration for the FTC_FIELD and FTC_PIT routers. Out of the 11 teams, we only had 2 problems with Samanthas in getting the flash to work properly (the FTC_FIELD worked, FTC_PIT didn't). So those two teams had to be tethered in the pits to practice. But no one had any problems communicating with the FTC_FIELD router.

We did have 2 issues during our qualification matches. One team got hit hard and Samantha dropped communications. The other, the NXT locked up and wouldn't respond to anything (we saw that happen with Bluetooth as well). Samantha stayed connected to the FCS during the lockup, so I don't know what happened there.

One thing that was great was that we didn't have any problems getting the teams back up and running for matches 2 through the end when they reported back to the field. The teams put the robots on the field and turned them on and the FCS found them right away and we were ready to start the next match. As a tournament organizer, I find that to be the best leap in progress with working with these robots with a centralized FCS. So, don't be too hard on Samantha yet.

So, a couple of tips that the teams and organizers should know:
1) Teams: Do not bring your routers to the competition. Keep the wifi to a minimum to keep it open for the competition.
2) Organizers: Make sure you set up the FTC_FIELD on one channel of the WiFi spectrum and FTC_PIT on a different one. Having them on the same channel will just confuse things.
3) Teams: Make sure your Samantha is not buried in the bowels of your robot. It's best to mount it vertically and with the red button on the top (the actual antenna is on top of the unit).
4) Teams: Get a small 1 foot USB extension cord and plug that into the Samantha unit and zip tie that securely to Samantha and the bot. You can then plug your USB cable from the NXT into the extension cord. Then, when the organizers need to flash Samantha, you can just disconnect the USB cable from the extension cord and plug the flash drive into it. Then flash Samantha and reconnect the cable. This will also relieve any stress that directly affects the Samantha unit. Also, get a small USB A-B cord (1'-1.5' feet). Secure these cables to the robot with zip ties.
5) Teams and Organizers: If you do have two routers (FTC_FIELD and FTC_PIT), make sure you wait 30-40 seconds during the flashing process to get both network's information loaded onto the Samantha. The Red, White, Blue lights should light up in succession twice (once for the FTC_FIELD and the second time for FTC_PIT). Then connect to the FTC_PIT router while in the pits to test out the bot. When you come to the field for the first time, you may have to press the red button on Samantha to sync. Then you'll be set for the day.
6) Teams: Make sure you compile and download the Samostat program to your brick. You can find it two folders under the Program Files\Samantha Field Control System folder. One for LABView and the other for ROBOTC. Pick the appropriate one for your system and install it on the brick. FTAs will use that program to see your configuration status for Samantha and make sure you can talk to the field and pit routers respectively.

I hope this will help you. Good luck to all the teams and all event organizers out there.

Re: [FTC]: Samantha? Like it or hate it?
 

I just realized something about what may have happened at Clarkson. When you went through the final phase of inspection and did the testing match, the FTA working the pit loaded the samantha wifi configuration. This configuration must have been the FTC_FIELD configuration, because it's the same configuration we used on the field. emmel said that at georgia the had a FTC_FIELD router and FTC_PIT router, meaning that if you were testing in the pit you would have to load the pit configuration and if you went onto the field you would load the field configuration. Now at Clarkson we had an area to test your robot with samantha in the pit, but never had to change configuration if we were on the field and then went to the pit and vice versa. Meaning that we had two seperate routers running the same configuration, while the matches were carefully looked over it was almost like it was free rein in the pit. If you wanted to run a test match you just need a field tech to come over and start the match. I feel like every time I came out of a match I saw people on that pit field. So what I'm trying to say is that at Clarkson we had two routers running the same configuration, and sometimes running matches at the same time, this seems exactly the kind of situation that could lead to the problems we saw.

Re: [FTC]: Samantha? Like it or hate it?
 

Actually, the Samantha holds TWO configurations at one time. It can know how to connect both to an FTC_FIELD and an FTC_PIT at the same time. That is why they did not have to load a separate configuration for each area.

Re: [FTC]: Samantha? Like it or hate it?
 

Exactly right. David beat me to replying.

Re: [FTC]: Samantha? Like it or hate it?
 

Just coming back form the Richmond Regional, I have to say that Samantha worked much better than the Bluetooth solution from last year. Matches all ran smoothly throughout the day. There were 4 communication issues my team encountered today. Twice, our NXT froze in the middle of matches after sustaining a shock during normal game play. Samantha stayed connected on both occasions. Second, one of our alliance partners lost communications with the field. The cause of the disconnection was a poor power connection. The last was a miscommunication with the field staff about which controller set my team was using during an elimination round. None of these were do to the Samantha module.

Re: [FTC]: Samantha? Like it or hate it?
 

the later posts in this thread seem to validate that the Samantha unit is working but we do need to learn what causes large scale crashes to improve on the best practices for tournament organizers and team behaviors. I think the post by emmell is a must read at this point for everyone either competing in or running FTC events.

Re: [FTC]: Samantha? Like it or hate it?
 

I don't think the posts in this thread are indicative of a 'lack' of problems that were experienced.

1.) The FTC organizers need to send out something official to all of the teams in TIMS about best practices in mounting the modules. Go to an FTC event and ask around about ChiefDelphi ... very few (rarely ever a first-year team) have heard of the website.
2.) Telling students their battery voltage dipped during the match (which is why the module dropped out), yet not allowing the students to see how bad the drop was (length of time, amount) in order to determine whether or not to return a brand new 13.7V battery back to the mfr. is not the way an FTA MVP should treat people he wants to sustain within his program long term
3.) If we're expected to have proper battery voltage meters, SEND IT OUT IN AN OFFICIAL UPDATE. As 'smart' as the mentors are, we are incredibly dumb about the many things we can't even fathom postulating, let alone knowing we need the something. (The flip side it true as well)
4.) Fact: if we ever change communications modules again in FTC, we will forgo the FTC program. Sure the 4 teams we have are nobodys, but we've gone through this exact experience twice now. A robot sitting still on the field doing nothing is not a way to 'Celebrate' the accomplishments of the students. We are tired of being an 'experiment' for the lowest bidder. It is very obvious the Samantha modules were not shock tested one bit. Even with a proper USB attachment to the frame, I could thump the thing and reset it.

Re: [FTC]: Samantha? Like it or hate it?
 

I just want to make some suggestions about the previous post:

I beg to differ. FTC has sent out something official. Read all of the Team Email blasts that have been sent. The blast on 11/18 had a link for a white paper with a diagram of how best to mount the Samantha module. You can find the email blasts here: http://www.usfirst.org/roboticsprogr....aspx?id=18132
I won't comment on what the FTA told you at your event, however you don't need a voltage meter at a competition. Your NXT will tell you what your battery levels are and so will the FCS if you are running it with the FTC_PIT configuration. If your NXT is >7.5 volts, then you're good. Anything less than 7.0 volts will probably not work well. For your TETRIX battery, anything greater than 11.0 volts is good and < 9.0 volts will not run. The FCS will light with Red, Yellow, and Green in the team box for these conditions. This is documented in the FCS manual.

I won't comment on the 4th item. Just pointing out the facts. The key for all the mentors and teams out there - READ EVERYTHING THAT YOU GET. It's important information and will help you be better prepared for your next event.

Good luck teams!

Re: [FTC]: Samantha? Like it or hate it?
 

The biggest problem I personally found in how the regional in St. Louis occurred was the determination if a match should replayed. This is nothing against the referees as they were forced to make decisions on the spot in order to make sure the competition continued to run smoothly. This, I feel, is more a problem of the rules.
The referees decided to only replay one match throughout the day. The reasoning for replaying this match was because the referees felt that there had been a "significant" impact to the outcome of the round. The rules need to be rewritten to account for factors such as this to avoid confusion and make it easier for the referees. There were many tempers that were ignited because of this specific round being replayed, while others had not been replayed - a rule would redirect anger away from referees who already have other frustrations pointed in their direction.

Re: [FTC]: Samantha? Like it or hate it?
 

I beleive the reasoning was because that signifigant impact to the match was determined by the FTA to be a direct result of the field. The other matches which were not replayed were not determined to be caused by a field fault.
Of course we can argue all day whether certain communication issues where because of the field control system or because of individual issues such as loose wiring on samathas, but and the end of the day, I think the refs and FTAs already make their decisions as best they can based on what they have available to them in a fair manner.
Perhaps there simply needs to be better communication to teams when such decisions are made?

Re: [FTC]: Samantha? Like it or hate it?
 

New information from an informant at Clarkson shows that some of the problems may have resulted from poor setup on Clarkson's part - I don't know the details of it, but it sounds like not quite everything was set up right and/or tested realistically.

Re: [FTC]: Samantha? Like it or hate it?
 

In terms of router naming, one issue I ran into when running a scrimmage out in Oregon, was the school I was at already had a router named "FTC_FIELD", which I didn't know at the time. I think it got turned on part way through the morning, and I suddenly had 1/2 my teams complaining they couldn't connect.
Once I tracked that down, I decided to put custom names on all my competition routers. That way if someone accidentally turns on a FTC_FIELD router at a competition, my network won't collapse. I also plan on running around with a WiFi scanner and disabling any rogue access points.

Re: [FTC]: Samantha? Like it or hate it?
 

My understanding has been that the FCS connects to FTC_FIELD by default whenever it is present. It only looks for and connects to the secondary SSIDs when there is not an FTC_FIELD present.

We've competed up here for the last two weeks. The first event was late in getting started because of interference from routers running their own FTC_FIELD. After that problem was weeded out, the event ran smoothly, for the most part.

This weekend, there were fewer problems with conflicting network names, though we did have some trouble with persistent intermittent connection loss -- if that makes sense -- and it resulted in some pretty terrible consequences to teams and robots. The folks running things were great about troubleshooting it and rerunning matches as necessary, but it still meant that several robots broke or were broken because of our inability to properly control the robots.

The wifi system operates better than the bluetooth system, but I wouldn't go so far as to call it a good system.

Re: [FTC]: Samantha? Like it or hate it?
 

The behavior was actually changed in a newer version of the firmware (which should have been installed at your competition). Samantha has two network configs stored in it (typically FTC_FIELD and FTC_PIT, but can be anything). It will toggle between then approximately every 6 seconds, until a FCS attempts to connect to it, and then it will remain on that network until power is cycled.


I'll consider it good if I can get through my 7 tournaments without having to babysit the connections of every single match. (Because, it sure felt like I had to do that with bluetooth last year)

Re: [FTC]: Samantha? Like it or hate it?
 

The only thing I'll say that's definitely positive about the Samantha module is the fact that we no longer have to lug a laptop and controller pair around. Our teams (at least) understood the nuances of bluetooth enough to remove all connection issues (usually reset the stack on the laptop and then reset the brick every 5-6 matches). We only shut off once throughout all of last year, and video revealed that was because another robot's outer mechanism went into our robot and wound up hitting a button on the NXT. If we could at least figure out what's going on with the Samantha, the kids really wouldn't care if they had to babysit it again ...

I would like to thank the feedback in this thread that points out helpful tips -- these things will definitely be passed on since often times other teams I've met barely have the capacity to program the thing to begin with let alone read every email, blog, and forum thread on the subject. We'll see how things go at the next qualifier in January.

Re: [FTC]: Samantha? Like it or hate it?
 

Folks,

This system seems to be extremely vulnerable to malicious mischief - Well intentioned people are shooting themselves in the foot. What happens if that one bad apple shows up in the stands? Does it need to be made more mischief-proof for next season?

Blake

Re: [FTC]: Samantha? Like it or hate it?
 

Blake,
would you mind expanding on that statement? I'm not sure I know what you mean.

Re: [FTC]: Samantha? Like it or hate it?
 

I am not Blake, but--

One of the field controllers/queuing station operators from the PA championship of last year told me they had to ask a person in the stands to leave the competition room. Apparently the person was holding a cell phone or similar device, pointing it at the arena, and broadcasting some kind of Bluetooth signals.

Re: [FTC]: Samantha? Like it or hate it?
 

I think Blake was talking about the current system that is not bluetooth. This is why I am confused.

Re: [FTC]: Samantha? Like it or hate it?
 

If the "FTC_FIELD" that has been diccussed below is a WiFi SSID, and if the Robots (automatically?) connect to FTC_FIELD (or to some other well-known SSID); then isn't it pretty easy for me to innocently (see other posts) or maliciously start up a WiFi device that broadcasts an FTC_FIELD SSID, and consequently foul up teams' connection attempts.

Blake

Re: [FTC]: Samantha? Like it or hate it?
 

Dealing with innocently is fairly simple to do, and is likely the bigger issue. FTAs just need to ignore FIRST's instructions, and use a unique SSID for their competition & practice routers.

Maliciously is harder to avoid, but I'm less worried about that. FRC has been using WiFi for several years now, and I haven't heard of any major issues with bad actors there.

At the tournaments I (as FTA) am running though, I will be actively running WiFi scanners and tracking down any APs that don't belong to the venue. This should hopefully reduce the threat of these issues, as well as know when it is an issue that is affecting matches.

Re: [FTC]: Samantha? Like it or hate it?
 

Technically the FTC_Field is supposed to be password protected and each Samantha module is "programmed" with the correct password to connect to the secured FTC_Field network. This is done during software inspection. So, if a robot hasn't passed software inspection, it won't have the configuration file to allow the Samantha to connect to the right network.

Yes, somebody could still have a rouge FTC_Field network in the stand, but any robot that has been inspected would only connect to the correct wifi network.

This doesn't mean that somebody cannot "play" the system and use it to their advantage. I am not going into details into some of the scenarios that my FTA has shared with me.

Jeff

Re: [FTC]: Samantha? Like it or hate it?
 

Unfortunately, it's not quite that simple. Even with the password, two APs with the same name will confuse Samantha, even with a secret password. I had a field go down during a scrimmage in November becuase of that exact reason. (Hence my decision to use non-standard names for all future events)

Re: [FTC]: Samantha? Like it or hate it?
 

The samantha will attempt to connect to the FTC_Field network with the strongest signal strength - from my experience, testing the samantha with two APs broadcasting FTC_Field with different passwords. Even after the samantha is given a password to use, it might just continue attempting (and failing) to connect to the rouge FTC_Field.
Now I would hope the samantha, once it is initially connected to the correct FTC_Field and FCS, would stay locked in through whatever protocol it uses to identify with the FCS but after seeing robots randomly disconnect I do not think that the protocol has this kind of a lock built in.

Random Dude's solution, I believe is the best. You might want to set your AP's to have hidden network names so that someone can't change their networks's SSID to be the same as yours. Are the FTA's allowed to change the initial configuration file that is put on the samantha during inspection? When my team was inspected (one of the first teams), the USB drive was taken out what looked like official packaging.

Regardless of all of that, if someone is trying to create problems with wifi, especially from the stands, they will likely fail because of signal strength. The fields are much closer to the official AP's than they would be to any rouge AP's (or at least they should be). Now there are signal focusing and boosting devices, but they should not be too hard to spot.

Re: [FTC]: Samantha? Like it or hate it?
 

I think we all need to take a breath here. We are talking about someone contentiously and maliciously cheating in a FIRST competition. This is not your average population we are talking about here. GP is not just a phrase we use in front of judges, right?

Re: [FTC]: Samantha? Like it or hate it?
 

Yesterday we had multiple disconnections during matches (even finals) at the NJ Frozen Frenzy Qualifier. This wouldn't be so much of a worry if it was just miscommunication between Samantha FCS people and the teams. That could be solved. But what usually happened was completely unexplained disconnections - sometimes making the NXT freeze up while driving and burn out the motors, sometimes just not running at all, sometimes shutting some teams off while other teams run and then turning them all back on. It just seems like Samantha is still in the testing phase. Or, at least, if they have figured out these problems, they haven't made it clear how to diagnose and fix them. I'm glad they're taking initiative - but I think switching over while Samantha still has some bugs is a bad idea.
Of course, I'm probably just bitter. I'd be a lot more open to it if it didn't cost my team 60 bucks every time we burn out our motors.

Re: [FTC]: Samantha? Like it or hate it?
 

All of the FTAs have to setup their own router. Most will likely follow the official FIRST instructions, which use FTC_FIELD and FTC_PIT, (with a site chosen PW on FTC_FIELD). The USB drives used by the inspectors are created by the local FTA. I'm the head Oregon FTA, so thankfully I don't have to run any competitions until the end of January.


See, this is partly due to a stupid bug in the FIRST teleop template (at least the RobotC one.) If communication is lost between to the brick, the robot keeps receiving the same joystick values it had been. Therefore, if you had been driving forward, your robot would keep driving until someone physically turns off the power. This can actually be tested under direct USB tether. Just drive the robot forward, and then yank the usb cable. I started coding a fix, but I need to send it off to FIRST so they can include it in next years competition. If someone knows if this applies to LabView as well, it would be appreciated.

Re: [FTC]: Samantha? Like it or hate it?
 

No it's not the average poulation. But the PA field operators at last year's PA championship event were apparently convinced they saw an attempt to do exactly that.

Re: [FTC]: Samantha? Like it or hate it?
 

I find that hard to believe.

Re: [FTC]: Samantha? Like it or hate it?
 

Ah that sounds promising as long as more FTA's have the same foresight as you and switch to custom WiFi network names.

This appears to be handled in Labview - I think all the templates that I have have this, because if an "Offline" message is sent to the NXT, the template is set to give the motors a power value of 0 and set the servo's to 0.
However, the problem normalmutant describes is with the NXT freezing after communication had been lost which would require the NXT's battery to be removed and re-attached for the NXT to be reset. (Or the reset button on the NXT to be pressed):
My team and sister teams, luckily, did not have this problem during competition, but I do believe some of the disconnects did have this problem. I do know that this is not necessarily the Samantha's fault, because it did occur when using Bluetooth. I have seen it happen with the Samantha's during testing. I feel like its more likely a problem that the NXT has with disconnections. I do not know how to recreate the problem, but I have witnessed it with 3 different NXT's and 6 different laptops when using Bluetooth and 3 NXT's, 3 Samantha's, and 3 laptops when using Wifi (samanthas).

Re: [FTC]: Samantha? Like it or hate it?
 

Sorry, I realize that my previous post wasn't accurate. A better description of it is that when the Samantha FCS stops working, it either shuts off completely, or continues sending the last signal it received from the joysticks. That's what I meant by "freezing up". This makes it harder, though, because the program can't tell when Samantha stops working - the signal it gets seems perfectly normal to the NXT.

Re: [FTC]: Samantha? Like it or hate it?
 

It's actually not specifically a samantha issue. The same thing can (and does) happen over bluetooth, and even potentially direct USB tether (if one were to pull the cable out). The joystick.c template fails to get any packets from the controller, and just assumes the values should remain the same. (instead of entering a failsafe mode)

Re: [FTC]: Samantha? Like it or hate it?
 

If what normalmutant is saying about the Samantha locking up and continuing to send the same packet to the NXT is accurate, then a fix to the template may not work well without additional design changes? Your idea for a template fix to JoystickDriver.c as I understand it would rely on detecting that new packets are not being received so that you could stop sending the last known good one back in the joystick struct. If the Samantha cannot detect a drop and keeps sending the NXT old packets as if they are new ones, the template may not have enough info to easily know the difference without resorting to comparing the payload state of each packet to previous ones.
The "additional design changes" I mention above may be to add an incrementing id to each packet payload which could be used to easily identify if they are new or not by any downstream receiver (Samantha or ROBOTC/LabView code) and even allow tracking of dropped/missed messages.
Thoughts?

Re: [FTC]: Samantha? Like it or hate it?
 

It doesn't need to be in the template. You can write your own and include it in your code. An example that could work is below.

Note that if the Samantha does keep sending the last packet, this won't work. But do we know for sure this is the case?

There's another problem I've seen occasionally that looks like a Samantha issue but isn't. If the I2C bus disconnects for a moment, it doesn't always re-attach correctly and thus the last message sent to the is continuously active. RobotC doesn't seem to have a means to verify and/or reset communication to the controllers programatically. That would be something that would REALLY help the issue.

Part of the complaining about Samantha is probably valid, but often it's the "newest thing" syndrome. When something doesn't work, the automatic blame goes to the newest thing. Even if the real issue has been there all along, or is something else.



Here's an idea for comm loss monitor code:

Re: [FTC]: Samantha? Like it or hate it?
 

I honestly can't say much about this question because it is my rookie year in FTC. but from what i know from technological evolution i conclude that the Samantha system does its job pretty well for its first year of mainstream FTC competitions.

Re: [FTC]: Samantha? Like it or hate it?
 

I just FTA'ed at a small regional and we had two of the problems mentioned here: Signal drops and NXT lock ups.

Excepting the occasional loose wire, the signal drops were caused by low 12v batteries. However, I'm reluctant to blame that on the teams. The FCS uses essentially open circuit voltage to determine the state of charge. That is problematic, as a moderately discharged battery can still show green. Then, as soon as a load is applied, the voltage drops below the Samantha minimum and the module resets. We were fortunate in that our tournament had a 3-hr built in break. During this time, all the teams fully charged their batteries and the problem vanished. Teams that did all their practice and testing using tethering or bluetooth would never see this issue until their tournament. And teams that use many heavily loaded dc motors will be much more vulnerable to dropouts.

An inelegant fix for next season is to run samantha off of an independent battery.

NXT lock ups were the other issue. The only pattern I saw was that some robots never had the problem; the robots that did, however, had it repeatedly (but not consistently).

Re: [FTC]: Samantha? Like it or hate it?
 

That pretty much mirrors what I've been seeing in Oregon in the 4 tournaments we've had so far. We've only had 1 NXT lock up, but Samantha losing power happened with some regularity. I definitely agree with the weak vs strong battery data.

As much as I don't like having another battery, I'm tempted to suggest to FIRST that Samantha have it's own. (I may also experiment with some of my local teams during the off season). The other thing I think will help would be splicing samantha directly into the battery connector, instead of way out at the end of the motor chain.

Re: [FTC]: Samantha? Like it or hate it?
 

I wonder why they can't run the Samantha core from the NXT's battery.
Does anyone know if the NXT can provide power on the USB connector?

It Looks like Samantha sends the NXT battery voltage to the FCS. Is it reading it directly?

On a different track... it seems to me that the Sam is always showing a battery voltage that is low. I wonder if there is a series rectifying diode in the power feed. There's 0.6 - 1.0 volts that could be reclaimed :)

Re: [FTC]: Samantha? Like it or hate it?
 

One of the cool things about samantha is that teams can no longer goof and start the match with their power switch off. Powering samantha off a third battery could reintroduce that issue. That said, it would be pretty simple to put a relay in the circuit and have both the samantha battery and the main 12V battery controlled by the existing power switch. Or, perhaps even easier, replace the existing SPST switch with a DPST switch hooked to two batteries.

Re: [FTC]: Samantha? Like it or hate it?
 

Although you can't start the match with the power switch off, there's still the problem if your Motor controller controller cables are unplugged.

Now that teams are relying on the Samantha module to report "no power", they sometimes forget to check the NXT screen for 12V levels. The NXT reads the 12V level through the motor controller, the Samantha does it via it's own power cable.

We had an instance where the FCS said everything was OK, but nothing moved. After the match we found that the NXT was reading 0V for the battery..... The motor controller cable had become unplugged. D'OH!

Phil.

Re: [FTC]: Samantha? Like it or hate it?
 

Thanks for the info aklego. I wonder what it'd take for FTC affiliate partners to have a battery tester (load tester) at the FTC events for teams to use. Perhaps it could be at the field table under FTA supervision ... sure they're cheap and individual teams could attain them.

However, it's the 'I didn't know I needed to know that' which is the most irritating aspect of the Samantha module, and such a battery load tester would incontrovertibly point to the correct problem if employed by the FTA.

Re: [FTC]: Samantha? Like it or hate it?
 

Not sure that that would be practical, or even neccessary.

FTC robots place hugely different loads on the batteries (just stall 4 motors to see what happens to a bettery). What would be an appropriate load to test at?

During practice and Auto testing, we've learned that if the *NXT* is reading the robot's 12V battery at less than 13.0V (when at idle) then it's time to change the battery. (Calling them 12V batteries is missleading). In fact, at competiton, we don't let them get below 13.5V before changing.

Strange things start to happen to the Motor/Servo Controller interfaces when the idle voltage drops under load, so if you want reliable control (regardless of the Sammantha Module) you really need to watch your batteries.

At least with the Samamtha you can see the instant loss of link if it occurs (the white light starts blinking).

Some other tips....

Make sure the Samantha power is the FIRST thing in the power chain (not at the end of the chain after two motor controllers.)

Consider splitting the power from the switch and running dedicated wires to the Samantha Module and the first motor controller. It's legal if you use the correct gauge wires. We splice and then heat shrink the splice.

Charge at the low rate. Overheated batteries don't last as long as cool ones.

Re: [FTC]: Samantha? Like it or hate it?
 

Have to ask the question here (because I honestly don't know the answer)

Why?

Electrically it is all the same wire. Internally in the controllers the two power connections are jumpered together...

The only reason I can come up with is that the Samantha is less tolerant of intermittent connections. And if your module is at the end of the chain, there's more chance of an intermittent connection affecting it. If, however, you make sure there are no intermittent connections in the first place, it doesn't seem necessary.

OK, you could potentially have a voltage drop over the wire, but at 13v, even with 8 motors all at stall (about 56 Amps -- maximum current) after 2 continuous feet of 16AWG wire (absolutely the worst case I could come up with) you would have a drop of only about 1 volt. Under "normal" 8 motor heavy operating situations (average 1 foot, 28 amps), your maximum drop is about 0.3v). That's not enough to cause a problem if your batteries are reasonably charged enough in the first place!

Re: [FTC]: Samantha? Like it or hate it?
 

I guess this is where theory vs reality comes into play.

If you assume that those tiny screw terminals provide perfect electrical contact, and that the students wiring said terminals do a perfect job of stripping and inserting the wires, then you are correct.

However, IMHO the reality of the situation is very different. Many kids will nick a few wires when stripping (there goes a few % in cross section). Maybe not all the strands get crimped tightly under the screw (there goes a few % in cross section). Maybe the wires get compressed and as a result it releases the tension from the screw (there goes a few % in cross section and adds a few ohms of resistance). Before you know it, 12 screw terminals (up and back) make the wire look pretty imperfect.

Every mechanical connection is also a potential failure point (complete or partial) and a less than perfect connection provides less than perfect resistance, inductance and capacitance.

Finally, I personally don't know what's between the power in and power out terminals on the servo and motor controllers (since I haven't pulled a controller apart) so who's to say there isn't an inductance that your meter isn't seeing (but a 40A spike will see).

Since these robots get severly beaten around, the more mechanical connections in a chan, the more it increases the likelyhood of an intermittant connection getting noticed.

Since I can eliminate any chance of the Samantha seeing a power glitch from any one of those (14) connections just by splicing off the main switch cable, seems like no-brainer insurance to me.

Phil.

Re: [FTC]: Samantha? Like it or hate it?
 

Samantha was easier to use than Bluetooth. We had very few problems with Samantha and the problems that we did have were easy to fix. It took us a while to figure out how to set up and configure the Samantha but that was because Samantha was new and none of us knew how to use it. We followed the directions that were on the FIRST website and played around with it and we got it to work. Most of the problems we had involved the computer not connecting to the router or not using the correct templates for autonomous and teleop. The only other problem we had more than once was when the Samostat said that the IP address of the Samantha was 169.254.___. __. That problem was easy to fix all we had to do was turn the robot and the brick off and then turn them back on. If that didn’t work we unplugged and then plugged back in the router or reconfigured the Samantha. Our Samantha died at the Maryland competition for unknown reasons but my guess would be that it had something to do with being in a cold car for too long or something like that. We had problems with FCS not connecting to Samantha when the computer did. Trying to rescan for the Samantha didn’t work so we had to exit out of the FCS. We had to turn on the Samantha before we looked for it using FCS or it wouldn’t find it even if we rescanned. Better instructions for setting up the Samantha would have been helpful. The only complaints I have about Samantha are that we could only get one which meant that if it broke we were screwed and that some of the tech people at the Maryland state and Pennsylvania York qualifier competitions knew less than I did about Samantha and FCS.

Re: [FTC]: Samantha? Like it or hate it?
 

I'm FTA'ing at our state tournament and just encountered an odd issue that is extremely successful at preventing Samantha connections. A team.gif of the wrong size on the NXT will totally foul up the works. It makes the FCS post a variety of errors.

Credit where credit is due. The kids figured it out.

Re: [FTC]: Samantha? Like it or hate it?
 

Whew. I just finished FTA'ing our state championship. I'm sold on the concept of samantha but not the current hardware. I FTA'ed at a regional several weeks ago and there were huge differences. At the regional, NONE of the teams had used samantha before. (All were from rural Alaska and their schools were 100% Mac based, hence no FCS.) As a result, all of their modules were brand new. We plugged them in and, excepting the low battery issues, they worked perfectly.

Yesterday was quite different. (We had some interference from an existing network that was jumping channels but that was quickly resolved and the affected match was replayed. And, contrary to rumors, there was not a jammer in the building.) The biggest issue was the samantha robustness. Or, more correctly, its lack thereof. Known powerhouses that had been using their modules for months were the ones having problems. Their modules had intermittent faults. Most frustrating, unless the module was really toasted, the problems would only occur during a match. The culprit, confirmed by the onsite FIRST rep, is weak solder joints. The "Samantha Best Practices Guide" is only a bandaid, and does nothing for teams that may have inadvertently damaged their module before it was published. We also had lots of locked up NXT's and the previously mentioned guide would indicate that samantha hardware faults were again the cause. Burned out LED's were also not rare. Bluntly, samantha was beta tested on 1,645 unsuspecting teams this year. The test results are in and the samantha hardware did not pass.

FIRST would do well to publicly admit the issues sans candy coating and explain how it is going to be rectified next year. It is safe to say that teams are tired of control issues.

As an aside, one thing that would be helpful would be to provide significant realtime information to teams. The small battery icons next to team numbers on the timer display are a great start but they are hard to see, especially in the heat of battle. I would not have been adverse to having a rep from each team looking over my shoulder at the FCS screen--It would have made my job easier for teams to see the disconnects as they happen.

Having said all that, from the reports of some events, our tournament was an unqualified success. We had 40 teams, each had 5 matches and we finished qualifiers a mere 15 minutes behind schedule.

Re: [FTC]: Samantha? Like it or hate it?
 

I diagnosed a related issue last night.

An intermittant Network connection issues was traced back to an intermittant power connection at the Sami module.

Turned out NOT to be the module, but the plug-in cable/connector combo.

On closer inspection the red wire seemed stressed at the entry point to the white plastic connector, and slight wire jiggling could cause the Sami to reset.

The Sami module was tested on a spare power cable (where the heck did that come from ??????) and was proven to be robust. So we replaced the cable. All was good.

We disected the "stressed" part of the suspect wire, and found NO broken conductors. We can only assume that a prior incident had caused the actual metal barrel of the power plug to become deformed (spread) enough that wire movement caused intermittant connections with the mating part inside the Sami module. VERY hard to diagnose, but causes problems whenver the robot took a hard bump.

Once again, this is a VERY rough and tumble environment and teams MUST be educated on how to tie down cables and protect connectors. I'm still amazed to see how many NXT's and Batteries fall out during a match.

As an aside... I can't imagine LEGO ever assumed that the NXT USB cable connector would see the wear and tear that FTC is now forcing it to endure. Multiple plug/unplug cycles during code testing, then it becomes a CRITICAL link for the actual competition. This is probably a $0.50 part.

Seriously !!!

Phil.

Re: [FTC]: Samantha? Like it or hate it?
 

Loose power connectors was definitely an issue. About 20/74 teams here in Oregon were affected bad connectors causing power loss to Samantha. Bad connectors was definitely one of the top causes of field problems.

As far as I could tell in the field, the female half of the plug was getting enlarged, perhaps due to side to side wiggling of the connector when being connected/disconnected. I instructed teams to squeeze it smaller (with either needle nose pliers or a small screwdriver), and that seemed to make things better.

Re: [FTC]: Samantha? Like it or hate it?
 

Our programmer thinks the problem is deeper than that. To show us, he held the power and USB cables and shook the samantha module around without it losing connection. He then put it on a robot and ran the robot the field wall, and it lost connection. He says it might be the hardware inside the samantha, not simply the cables. We may look for what's wrong - it'd be great for us teams know what the main problem is before worlds.
But still, it's working better than the bluetooth FCS.

Re: [FTC]: Samantha? Like it or hate it?
 

Normalmutant, your programmer is correct. Try putting the module on your robot and establishing a connection with the FCS. Without starting a match, shake your robot and see if you can get it to drop its connection. Now try the same thing but with tele-op running. The FIRST rep at our event indicated motion induced drops are much more likely while the NXT and samantha are actively communicating, and my experimenting has shown that to be true.

From the info in this thread, it seems like there is not a single problem but, rather, problems that manifest themselves in nearly the same way:

Network interference--dropped connection
Poor power connection/wiring problems--dropped connection
Manufacturing defects in power cord (rare?)--dropped connection
Low battery (FCS initially reporting green)--dropped connection
Loose USB cord--dropped connection and/or locked up NXT
Bad solder joints--dropped connection and/or locked up NXT
Programming/firmware bugs--dropped connection and locked up NXT
Others?

Re: [FTC]: Samantha? Like it or hate it?
 

Has anyone here seen the following occur:

Establish connection from FCS to Samantha
Run TeleOp and hit wall or go over corrugate or get hit by robot
NXT "freezes", but FCS and Samantha still communication (LED light is still white). A freeze is when you press buttons on the NXT and it doesn't respond.
Have to remove battery from NXT to reset it.

If you have seen it, can you repeat it happening in the same way. If so, please IM me. I'd love to get some more information from you about this.

Re: [FTC]: Samantha? Like it or hate it?
 

Oh, okay. We guessed that there was a spike in the power level when the robot rams into a wall. We're planning to do some testing, too. We'll keep you posted.

That's happened to us and our sister team a couple of times. I don't know how to duplicate it.