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-   -   How to power Mini-PC on robot? (http://www.chiefdelphi.com/forums/showthread.php?t=154152)

team-4480 23-01-2017 21:24

How to power Mini-PC on robot?
 
Hi,

We have a mini-pc that we would like to use for some advanced image processing that can only be done on a full-fledged mini-pc. We wrote the code and tested it and it works great. Now the problem is powering it on the robot. On the AC-DC converter, it states that it outputs 19.5V @4.62 Amps. We found a 19V 5A adapter, but unfortunately, when we plug it in, the mini-pc beeps and gives a red light indicating that the power supply isn't good enough, likely due to the lower voltage.

Has anyone ever done anything like this, or does anyone have an idea on how to properly feed 19.5V to the mini-PC? Also, what are the rules regarding use a DC-DC converter?

Thanks a bunch in advance!

GeeTwo 23-01-2017 21:31

Re: How to power Mini-PC on robot?
 
R07, in the blue box letter I, forbids custom circuits from producing voltages in excess of 24 volts, making 19.5 presumably legal. If you can't find a 12V to 19V converter, I would recommend trying to find a 12V to 24V converter, then regulating it down to 19.5.

team-4480 23-01-2017 21:37

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by GeeTwo (Post 1635365)
R07, in the blue box letter I, forbids custom circuits from producing voltages in excess of 24 volts, making 19.5 presumably legal. If you can't find a 12V to 19V converter, I would recommend trying to find a 12V to 24V converter, then regulating it down to 19.5.

So this to this then?

Kevin Sevcik 23-01-2017 21:38

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by team-4480 (Post 1635363)
Hi,

We have a mini-pc that we would like to use for some advanced image processing that can only be done on a full-fledged mini-pc. We wrote the code and tested it and it works great. Now the problem is powering it on the robot. On the AC-DC converter, it states that it outputs 19.5V @4.62 Amps. We found a 19V 5A adapter, but unfortunately, when we plug it in, the mini-pc beeps and gives a red light indicating that the power supply isn't good enough, likely due to the lower voltage.

Has anyone ever done anything like this, or does anyone have an idea on how to properly feed 19.5V to the mini-PC? Also, what are the rules regarding use a DC-DC converter?

Thanks a bunch in advance!

The rules that would apply to you are R49, customs circuit may not produce more than 24V, and R10, no individual item may exceed $400 in cost.

I'm told R49 is now in place because someone had a 12V to 120VAC inverter on their robot as their solution to a problem like yours. Kudos to you for not trying to electrocute your inspector!

What brand and model of mini PC are we talking about here? I just googled 19.5V car charger and came up with come likely candidates. I know for a fact that many laptops have an extra pin that transmits data about the charger so the laptop can be certain the charger is "safe"*. This may be a similar issue.

On this I'd be concerned about is how your mini PC is going to deal with riding on a robot. The advantage of raspberry pis, kangaroo pcs, etc. is that they're solid state and generally very compact. There's not much inside to get jarred loose and bounce around. Are you sure your miniPC is going to put up with a headon collision with a defender?

EDIT: Here's an adjustable DC boost converter that should work. Though it suggests you'll need a fan on it to pull 5A. While you're at it, have someone print you a case for it, or it's unlikely to pass inspection.

team-4480 23-01-2017 21:44

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Kevin Sevcik (Post 1635370)
The rules that would apply to you are R49, customs circuit may not produce more than 24V, and R10, no individual item may exceed $400 in cost.

I'm told R49 is now in place because someone had a 12V to 120VAC inverter on their robot as their solution to a problem like yours. Kudos to you for not trying to electrocute your inspector!

What brand and model of mini PC are we talking about here? I just googled 19.5V car charger and came up with come likely candidates. I know for a fact that many laptops have an extra pin that transmits data about the charger so the laptop can be certain the charger is "safe"*. This may be a similar issue.

On this I'd be concerned about is how your mini PC is going to deal with riding on a robot. The advantage of raspberry pis, kangaroo pcs, etc. is that they're solid state and generally very compact. There's not much inside to get jarred loose and bounce around. Are you sure your miniPC is going to put up with a headon collision with a defender?

Our HP EliteDesk Mini 705 G1 (The first computer on the page) ran 250 dollars. So I would have to find a charger that transmit a signal saying that our charger is safe?

We are really conveniently in the durability of our mini-PC. It will be mounted using the VESA mount on the back and maybe a couple of zip-ties just to be sure. It has an SSD so there are no moving parts inside the computer.

Adnewhouse 23-01-2017 22:17

Re: How to power Mini-PC on robot?
 
Something like this should work nicely and is perfectly legal on the robot: http://a.co/7VNpilJ

Kevin Sevcik 23-01-2017 22:18

Re: How to power Mini-PC on robot?
 
Meant to put an asterisk on that "safe". "Safe" in this case means both that it puts out enough amps, and that it's the correct brand, etc. Third party chargers don't work on Lenovos, for instance.

But I digress. What does the plug on the end of your AC adapter look like? Is it just the sleeve and barrel, or is there a pin in the center of it as well? Post a picture of it, if that didn't make sense.

EDIT: The rear view image of that PC on the web doesn't bode well. It looks like the power port wants a center pin, which carries that ID information, which, while spoofable, is pretty difficult to spoof.

EDITx2: Since it looks like you need that ID pin, you're back to first or third party laptop chargers. this might work if the OD of that connector is right. I'm afraid this is going to be a little hit or miss to get this working, though. Can you post the model number of the stock AC-DC adapter? If it can be matched up to a corresponding laptop, then you just have to find a car charger that's compatible with that laptop.

team-4480 23-01-2017 22:38

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Kevin Sevcik (Post 1635382)

EDITx2: Since it looks like you need that ID pin, you're back to first or third party laptop chargers. this might work if the OD of that connector is right. I'm afraid this is going to be a little hit or miss to get this working, though. Can you post the model number of the stock AC-DC adapter? If it can be matched up to a corresponding laptop, then you just have to find a car charger that's compatible with that laptop.

Yes, there is a center pin for the charger.

I will post a picture tomorrow of the official charger brick. Hopefully, we can figure something out. Thanks for the help thus far!

EDIT: Now that I think of it, I believe there was a third white wire when we stripped of the connector to test with our DC-DC adapter. Maybe we just have to apply a certain voltage on that wire and it will work?

Kevin Sevcik 23-01-2017 22:41

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by team-4480 (Post 1635390)
Yes, there is a center pin for the charger.

I will post a picture tomorrow of the official charger brick. Hopefully, we can figure something out. Thanks for the help thus far!

Yeah, that's a "smart" charger. Hopefully a pic of the label on the charger will let us cross reference a laptop it works with and then a third part car charger you can power from the PDP.

rich2202 24-01-2017 07:22

Re: How to power Mini-PC on robot?
 
IMHO, you should really be thinking laptop with a built in battery.

marshall 24-01-2017 07:34

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by rich2202 (Post 1635460)
IMHO, you should really be thinking laptop with a built in battery.

Actually, I'd say this device should be able to run off batteries since most PCs aren't designed to have power yanked from them or drop down randomly so running them from the ROBOT's battery isn't going to work. I'd say that independent battery power is "essential to completeness" to pretty much all COTS computing devices.

However, it is up to all of the LRIs with how they interpret the ambiguously worded rule about COTS device batteries. I know how I'm interpreting it until I'm told otherwise at an event by an LRI.

And based on Al's comments in a prior thread, as long as the COTS computing device's batteries don't interface with the control or drive systems for the robot, you should be following the intent of the rule in his eyes.

EDIT: Or don't test the rules and just use one of these after adjusting the output voltage: http://a.co/gd9yFkM

rich2202 24-01-2017 11:00

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by marshall (Post 1635462)
I'd say that independent battery power is "essential to completeness" to pretty much all COTS computing devices.

"Essential to completeness" is not the standard. Everything on the robot needs something else in order to work.

R37 says: "batteries integral to and part of a COTS computing device". There have been many discussions about batteries and the Raspberry Pi. Until someone sells a Pi COTS with battery, the Pi cannot have its own battery. Team 4480's computer is no different. Hence a laptop (notebook, chromebook, pad, etc.) with a built in battery is the preferred solution.

Just because you have an Operating System on your COTS computing device that does not like a random shutdown is not an excuse. If you had a more fault tolerant OS (and a fast booting one), you would not "need" the second battery.

marshall 24-01-2017 11:06

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by rich2202 (Post 1635554)
"Essential to completeness" is not the standard. Everything on the robot needs something else in order to work.

R37 says: "batteries integral to and part of a COTS computing device". There have been many discussions about batteries and the Raspberry Pi. Until someone sells a Pi COTS with battery, the Pi cannot have its own battery. Team 4480's computer is no different. Hence a laptop (notebook, chromebook, pad, etc.) with a built in battery is the preferred solution.

Just because you have an Operating System on your COTS computing device that does not like a random shutdown is not an excuse. If you had a more fault tolerant OS (and a fast booting one), you would not "need" the second battery.

I call shenanigans. Your logic is broken. Laptops do not require a battery to function and can run off of a voltage regulator just like mini PCs and raspberry pis. If we're forced to deal with corrupt operating systems and files then why does a laptop not have to deal with it?

Q&A was asked a direct question about allowing replacement batteries for COTS devices and they chose to answer by explaining that integral means "essential to completeness". You are picking and choosing what that means (Just like I am... see the problem YET?!?!)... and if you're an LRI then you are entitled but no one else is.

Bkeeneykid 24-01-2017 11:13

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by marshall (Post 1635558)
I call shenanigans. Your logic is broken. Laptops do not require a battery to function and can run off of a voltage regulator just like mini PCs and raspberry pis. If we're forced to deal with corrupt operating systems and files then why does a laptop not have to deal with it?

Q&A was asked a direct question about allowing replacement batteries for COTS devices and they chose to answer by explaining that integral means "essential to completeness". You are picking and choosing what that means (Just like I am... see the problem YET?!?!)... and if you're an LRI then you are entitled but no one else is.

Well it seems the Q&A explicitly disagrees: https://frc-qa.firstinspires.org/qa/284

marshall 24-01-2017 11:14

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Bkeeneykid (Post 1635560)
Well it seems the Q&A explicitly disagrees: https://frc-qa.firstinspires.org/qa/284

So I truly do not understand what FIRST is after here. If they don't want external batteries then specify that.

If they are going to allow batteries for laptops then I truly do not understand why they think laptop batteries are integral. They are not required for a laptop to function. They are not essential to completeness yet that is how they defined it so I'm left to think that a battery must be required for a laptop because if it loses power then it will potentially corrupt the OS or files. Any 1st year EE undergrad can tell you that a power source is a power source yet FIRST doesn't seem to think that. Maybe a cell phone has a battery that is literally required for completeness but that's not strictly true either. All of these devices can be run from an alternative power source like the robot battery.

Now they've said that USB power packs shouldn't be considered integral. Well, ok... what about this: https://www.sparkfun.com/products/13896

IT USES A USB BATTERY PACK!!!

Not to mention the custom circuit rules which allows for other things like this:
Ebay link for a supercap based system that should be able to charge from the robot battery

USB batteries aren't legal but yet this thing seems perfectly legal provided it charges from the robot battery and doesn't power anything on the robot's control system or motors. IT MAKES NO SENSE! It's not a battery after all, it's just a bunch of capacitors in a custom circuit. Bonus, it has a built-in USB port.

I'm committed to kicking and screaming about this for as long as it is ambiguous and believe me, we'll push boundaries on trying stuff.

I really implore FIRST to stop and think about what this rule is trying to accomplish and then explain the intent. At this point they are just being silly.

Jon Stratis 24-01-2017 11:20

Re: How to power Mini-PC on robot?
 
Marshall, I think you're reading too much into the Q&A ruling. It specifically says that "laptops are designed to have a battery" - even if the battery is swapable, that doesn't mean you're constrained to the one that originally shipped with the laptop, so long as you use a battery intended for use with that laptop by the manufacturer.

But I can't see a way to interpret that ruling to allowing batteries to be added to a computing device that is designed to be run off wall power. Before you try that route, ask a direct question on the Q&A, otherwise you're likely to be disappointed at competition.

marshall 24-01-2017 11:59

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Jon Stratis (Post 1635564)
Before you try that route, ask a direct question on the Q&A, otherwise you're likely to be disappointed at competition.

I did ask a direct question and got a "go read the dictionary" response. They were being cute with that response and they know it.

I'm already disappointed... nowhere to go but up from here.

Jon Stratis 24-01-2017 12:07

Re: How to power Mini-PC on robot?
 
Q138 was intentionally worded to be extremely broad, don't deny it. Any attempt to give a detailed response by the GDC would have likely opened up loopholes for teams to exploit. Instead, they gave a simple response that most people can conceptually understand.

Q284, on the other hand, was an extremely straightforward and narrow question, and as such got a straightforward and direct response. Be more like Q284.

marshall 24-01-2017 12:12

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Jon Stratis (Post 1635592)
Q138 was intentionally worded to be extremely broad, don't deny it. Any attempt to give a detailed response by the GDC would have likely opened up loopholes for teams to exploit. Instead, they gave a simple response that most people can conceptually understand.

Q284, on the other hand, was an extremely straightforward and narrow question, and as such got a straightforward and direct response. Be more like Q284.

Asking them to explain the meaning and intent of a rule is broad? I think not. I wasn't being cute. I was being sincere and trying to get a response.

I'd like to see one of two things:
A) Say that teams can use batteries for computing devices provided it is done safely and doesn't interface with the control or motors for the robot. This can be demonstrated by having the team turn off the robot and see what is still running.

or

B) Make the only legal source of power on the robot to be the ROBOT battery.

Bkeeneykid 24-01-2017 12:16

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by marshall (Post 1635594)
Asking them to explain the meaning and intent of a rule is broad? I think not. I wasn't being cute. I was being sincere and trying to get a response.

I'd like to see one of two things:
A) Say that teams can use batteries for computing devices provided it is done safely and doesn't interface with the control or motors for the robot. This can be demonstrated by having the team turn off the robot and see what is still running.

or

B) Make the only legal source of power on the robot to be the ROBOT battery.

Both of those options bring up a lot of concerns that I don't think FIRST will agree with. With option A, you have the potential of teams connecting batteries to things that really shouldn't have batteries on them. You'd of course need much more changes in the rules to define what is "safely and doesn't interfere with control or motors for the robot". Option B means a lot of devices are now back out of the reach of teams, which kinda negates the original purpose of R37's lower info box. It's much too late in the season to implement that choice, as many teams are already designing in Phones ala 254 last year, GoPros and other small devices. I'd be ok with that first option, just as long as there's an explicit regulation on what it can and cannot power. Honestly, a single thread on CD and a few Q&A posts are unlikely to change these rules, so I'm not seeing that this could be implemented easily this year.

Jon Stratis 24-01-2017 12:22

Re: How to power Mini-PC on robot?
 
I understand what you want, but the rule is not written that way. That certainly could change in the future, but there's a whole world of safety related stuff that has to be taken into consideration.

If a team is improvising a battery and power system for a computer, do there need to be rules around wire gauge and breakers for that system? Do we need to check the system for grounding to the frame? Do wires have to be properly color coded? It's a whole can of worms you would be opening up here.

Allowing integral batteries solves that problem. GO PRO cameras can use their integral batteries without worry about burning up wiring or shorting out. Laptops can use their integral batteries while avoiding those worries as well.

So, FIRST really has a choice... have a rule written like it is in order to ensure batteries for COTS devices are implemented safely, or add another section to the rule book and another dozen rules to regulate what teams can and can't do. Personally, as an inspector, I prefer being able to rule on this simply without having to dig through a bunch of different rules for a situation that doesn't really come up all that often at events.

marshall 24-01-2017 12:25

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Jon Stratis (Post 1635603)
If a team is improvising a battery and power system for a computer, do there need to be rules around wire gauge and breakers for that system?

It's a custom circuit. There are already rules.

marshall 24-01-2017 12:28

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Bkeeneykid (Post 1635599)
Both of those options bring up a lot of concerns that I don't think FIRST will agree with. With option A, you have the potential of teams connecting batteries to things that really shouldn't have batteries on them.

You really don't. Limit it to cameras and COTS computing devices and you have what we have now.

Also, S03 already covers unsafe robots.

Jon Stratis 24-01-2017 12:38

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by marshall (Post 1635606)
It's a custom circuit. There are already rules.

If we were to allow batteries like you want, please point out, in the current rules for custom circuits, what would stop me from putting a battery equivalent in capacity to the robot battery on board to power a custom circuit, and wire from that battery to the circuit with 28 gauge wire? Can you even pretend that situation should be allowed?

You would NEED rules just as complicated as our current power distribution rules for custom circuits if you allowed improvised powering of custom circuits from random batteries. For the sake of safety there just isn't any way around that.

Jon Stratis 24-01-2017 12:40

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by marshall (Post 1635608)
Also, S03 already covers unsafe robots.

So you're OK with an LRI arbitrarily looking at a battery powered custom circuit and saying "I deem that to be unsafe"? You don't want rules in place to actually tell you what is considered a safe setup and what isn't?

marshall 24-01-2017 12:42

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Jon Stratis (Post 1635618)
So you're OK with an LRI arbitrarily looking at a battery powered custom circuit and saying "I deem that to be unsafe"?

It's already a rule and happens all the time to rookie teams.

Chris is me 24-01-2017 12:45

Re: How to power Mini-PC on robot?
 
I think it's vaguely clear that by "integral", they mean, like, the battery isn't an external device that plugs into the power supply port in lieu of a regular power supply. A laptop not only has a cutout for a battery, but a port purpose built for its use, and hardware integral to the laptop to regulate its charge. I think it's not THAT hard to understand the Q&A on this.

All of that being said, I think the rule is stupid and pointless and has no business making this distinction. USB batteries for custom circuits should be allowed. I know they aren't, so I won't use them, but they should be. It's silly that they aren't allowed, and it arbitrarily makes some solutions (more expensive ones!) better than others (more accessible ones!).

Rules for USB batteries don't have to be complicated. Allow a USB powered custom circuit to connect to it using standard ports and cables only. Make it like pneumatics where you can't modify the cables or the battery or use custom wiring or whatever. Maybe even regulate the size of the USB battery if you must. This is not prohibitively difficult.

marshall 24-01-2017 12:51

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Chris is me (Post 1635621)
I think it's vaguely clear that by "integral", they mean, like, the battery isn't an external device that plugs into the power supply port in lieu of a regular power supply. A laptop not only has a cutout for a battery, but a port purpose built for its use, and hardware integral to the laptop to regulate its charge. I think it's not THAT hard to understand the Q&A on this.

All of that being said, I think the rule is stupid and pointless and has no business making this distinction. USB batteries for custom circuits should be allowed. I know they aren't, so I won't use them, but they should be. It's silly that they aren't allowed, and it arbitrarily makes some solutions (more expensive ones!) better than others (more accessible ones!).

Rules for USB batteries don't have to be complicated. Allow a USB powered custom circuit to connect to it using standard ports and cables only. Make it like pneumatics where you can't modify the cables or the battery or use custom wiring or whatever. Maybe even regulate the size of the USB battery if you must. This is not prohibitively difficult.

No no, we can't have common sense here! We must all argue with Marshall about hypothetical rules he made up to help explain what kind of answer he was after from the Q&A people and their silly actual rules.

Andrew Schreiber 24-01-2017 12:51

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by marshall (Post 1635619)
It's already a rule and happens all the time to rookie teams.

Or to any team that doesn't follow whatever inane whims some LRIs seem to have.



Pre-Edit: Don't read any subtext into this. If you think it's an attack on someone, it's not. Seriously, I'm not that subtle.

techhelpbb 24-01-2017 12:53

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by marshall (Post 1635561)
So I truly do not understand what FIRST is after here. If they don't want external batteries then specify that.

If they are going to allow batteries for laptops then I truly do not understand why they think laptop batteries are integral. They are not required for a laptop to function. They are not essential to completeness yet that is how they defined it so I'm left to think that a battery must be required for a laptop because if it loses power then it will potentially corrupt the OS or files. Any 1st year EE undergrad can tell you that a power source is a power source yet FIRST doesn't seem to think that. Maybe a cell phone has a battery that is literally required for completeness but that's not strictly true either. All of these devices can be run from an alternative power source like the robot battery.

Now they've said that USB power packs shouldn't be considered integral. Well, ok... what about this: https://www.sparkfun.com/products/13896

IT USES A USB BATTERY PACK!!!

Not to mention the custom circuit rules which allows for other things like this:
Ebay link for a supercap based system that should be able to charge from the robot battery

USB batteries aren't legal but yet this thing seems perfectly legal provided it charges from the robot battery and doesn't power anything on the robot's control system or motors. IT MAKES NO SENSE! It's not a battery after all, it's just a bunch of capacitors in a custom circuit. Bonus, it has a built-in USB port.

I'm committed to kicking and screaming about this for as long as it is ambiguous and believe me, we'll push boundaries on trying stuff.

I really implore FIRST to stop and think about what this rule is trying to accomplish and then explain the intent. At this point they are just being silly.

I would like to third that an external battery properly engineered - should be just as safe as a in integral battery. Considering that certain products known to smoke have integral batteries that were not properly engineered either.

I believe I understand the spirit of the goal with this rule - but I disagree that integral batteries insure proper engineering and external batteries are more risky.

If it's down the bare legal issue of having someone to sue - consider that most companies DO NOT recommend mounting their systems on a mobile robot so in a Court of Law they'll pull that out as a defense.

Unrelated to the quote above:

I disagree that a small PC that is not a laptop will fair poorly on a robot. I know of several HP Pavilion models (550 for example) that are miniITX motherboards in unusually large cases and take 19VDC power in. With the addition of a cheap SSD these would be no more likely to fail than a laptop and that style board is often mounted in large full size motor vehicles. Granted a full size motor vehicle has a suspension. Years ago someone told me on Chief Delphi that a laptop on a robot would fail if it wasn't as robust as a Panasonic ToughBook so I put a Dell Mini 9 (SSD) and a Gateway netbook (with a HDD replaced with an SSD) on a robot in a box merely padded with foam and drove it over the 6" bumps in the field that year hundreds of times without a single failure of any sort. Could it fail - sure. Did it fail - no. I have watched people drop average HP and Dell laptops down stairs in a padded case in hibernation and they come out in one piece and still work.

As far as how to produce reliable power for such a setup - I strongly recommend that someone boost their input voltage from the battery as high as they are legally allowed then buck it down to whatever voltages they require (use switching power supplies). If 24VDC is the maximum (likely because of the history of the cRIO) then go as high as that. If you don't do this you'll always have risk that the battery will absorb a heavy load and drop output voltage just enough to force a reboot.

If would be better if your PC could run off 16V or less because at 19VDC you only have room for the input voltage to dive about 5-6VDC before the only safety you have to insure a correct output voltage will be the temporary charge of the internal switching power supply capacitors.

Finally I am still game to produce a 3D printed or laser cut case with a Raspberry Pi and battery in it but the requirements for this are more about FIRST rules than some huge business opportunity. If someone wants to put the work in I am will to provide assistance if asked. I figure the goal should be to provide such platforms for a bunch of common FIRST coprocessors because frankly - many times the coprocessors in FIRST are each powerful enough to run a mobile robot outside of FIRST and there could be some opportunity there if that business later provides expanded I/O solutions for those platforms as well. If someone designs the case I have access to many 3D printers and the large format laser cutters at NextFAB in Philadelphia. I can also provide free web services and domain registration to reduce the operation costs. I can finally provide testing and prototyping for the electonic elements. As I have effectively made this offer for this 5 times now on Chief Delphi alone - please be aware that you'd be working on something for next year because this year is cutting it very darn close and if FIRST (understandably) asks for something to examine themselves you are leaving them far too little time to complete that evaluation.

rich2202 24-01-2017 12:56

Re: How to power Mini-PC on robot?
 
I initially saw the rule (COTS device with Battery) as a power limiting concession, but can also appreciate how it is a safety issue (did the team design the power circuit correctly).

A COTS device that includes a battery is an easy bright line to enforce. If you allow teams to install any battery, then what are the rules on what can get a battery? If a fire starts because a custom battery circuit shorted out, how do you turn it off?

I'm surprised that Samsung 7's weren't banned.

marshall 24-01-2017 12:58

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by rich2202 (Post 1635630)
I'm surprised that Samsung 7's weren't banned.

Shh! Don't ruin it for us.

Chris is me 24-01-2017 13:03

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by rich2202 (Post 1635630)
A COTS device that includes a battery is an easy bright line to enforce. If you allow teams to install any battery, then what are the rules on what can get a battery? If a fire starts because a custom battery circuit shorted out, how do you turn it off?

How do you turn off a laptop battery that's shorted out and started a fire? It's certainly happened before.

People aren't asking for "any battery" to be legal, just USB batteries of some shape or form. These are common devices, with a known output plug, voltage, and current. A restriction saying "COTS batteries that output 5V power over USB at 2 amps or less and 10,000mAh or less" for example would be reasonably narrow, wouldn't result in these strange nightmare slippery-slope kids-wired-a-battery-at-home-using-bare-copper scenarios people keep jumping to, and would fix this and many other problems.

Jon Stratis 24-01-2017 13:13

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Chris is me (Post 1635636)
How do you turn off a laptop battery that's shorted out and started a fire? It's certainly happened before.

People aren't asking for "any battery" to be legal, just USB batteries of some shape or form. These are common devices, with a known output plug, voltage, and current. A restriction saying "COTS batteries that output 5V power over USB at 2 amps or less and 10,000mAh or less" for example would be reasonably narrow, wouldn't result in these strange nightmare slippery-slope kids-wired-a-battery-at-home-using-bare-copper scenarios people keep jumping to, and would fix this and many other problems.

Chris, your interpretation of what's been posted here is very different from mine.

Quote:

Originally Posted by marshall (Post 1635594)
I'd like to see one of two things:
A) Say that teams can use batteries for computing devices provided it is done safely and doesn't interface with the control or motors for the robot. This can be demonstrated by having the team turn off the robot and see what is still running.

or

B) Make the only legal source of power on the robot to be the ROBOT battery.

There certainly is room for the rule to be expanded by the GDC without getting too crazy (such as allowing USB battery packs design to work with an arduino), but that's not what people have been pushing for in this thread.

marshall 24-01-2017 13:17

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Jon Stratis (Post 1635640)
There certainly is room for the rule to be expanded by the GDC without getting too crazy (such as allowing USB battery packs design to work with an arduino), but that's not what people have been pushing for in this thread.

https://www.cnet.com/how-to/three-th...ut-usb-type-c/

Quote:

USB 3.1 Type-C cables offer a transfer rate of 10Gbps, which is double the transfer speed of USB 3.0 (5 Gbps). Additionally, these cables will offer 20 volts and 5 amps of power, compared with the 5 volts and 1.8 amps of its predecessor. This means less waiting around for devices to transfer data or for their batteries to charge.
WOPR wins again... darn it!

Kevin Sevcik 24-01-2017 17:35

Re: How to power Mini-PC on robot?
 
Wow, 3 pages of replies to the poor guy that needed to source a weird power supply for his mini PC. He must be getting lots of help, I probably don't even need to... Oh.

So team-4480, have you gotten any more info on the stock power supply? I'd love to help you figure out an off the shelf solution for powering that.

team-4480 24-01-2017 19:55

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Kevin Sevcik (Post 1635803)
Wow, 3 pages of replies to the poor guy that needed to source a weird power supply for his mini PC. He must be getting lots of help, I probably don't even need to... Oh.

So team-4480, have you gotten any more info on the stock power supply? I'd love to help you figure out an off the shelf solution for powering that.

So here is the picture of the back of the power brick.

I did some searching on bypassing the "smart power plug" and there are some people suggesting that it has been done just to wire in a 2K resistor to the positive side and a capacitor to the negative and feed that into the white wire. Apparently, that white wire wants something like 12-13V.

Kevin Sevcik 24-01-2017 20:17

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by team-4480 (Post 1635861)
So here is the picture of the back of the power brick.

I do some searching on bypassing the "smart power plug" and there are some people suggesting that it has been done just to wire in a 2K resistor to the positive side and a capacitor to the negative and feed that into the white wire. Apparently, that white wire wants something like 12-13V.

This is not always the case. Some of those smart power supplies have a one wire communication chip that sends an actual digital code the laptop/PC is looking for.

At any rate, this car charger will probably work. It's listed as compatible with the same laptops that your stock charger is compatible with.

It has to be a boost charger of some sort, though there isn't a guarantee of how low an input voltage it'll work with. Still $20 for a potential off the shelf solution seems reasonable to me.

team-4480 27-01-2017 21:38

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by Kevin Sevcik (Post 1635875)
This is not always the case. Some of those smart power supplies have a one wire communication chip that sends an actual digital code the laptop/PC is looking for.

At any rate, this car charger will probably work. It's listed as compatible with the same laptops that your stock charger is compatible with.

It has to be a boost charger of some sort, though there isn't a guarantee of how low an input voltage it'll work with. Still $20 for a potential off the shelf solution seems reasonable to me.

We bought the charger and.....it worked! Thanks for the help! I don't know how long it would've took me before I realized there was a smart pin.

Also, the charger states it can go from 11.5V to 15V so it should work no problem as long as we have a full battery. Or maybe it may be worth to get booster to 14V just to be sure....we will see after actually testing it on the robot. Thanks!

Kevin Sevcik 27-01-2017 22:54

Re: How to power Mini-PC on robot?
 
Quote:

Originally Posted by team-4480 (Post 1637301)
We bought the charger and.....it worked! Thanks for the help! I don't know how long it would've took me before I realized there was a smart pin.

Also, the charger states it can go from 11.5V to 15V so it should work no problem as long as we have a full battery. Or maybe it may be worth to get booster to 14V just to be sure....we will see after actually testing it on the robot. Thanks!

11.5V? Eeeehhh.... You're going to want to test that on an actual robot. Battery voltage can dip shockingly low in a match. There's a reason the roboRIO has brownout provisions to kill speed controllers and shed load when battery voltage dips below 6.8V. This means the roboRIO will be perfectly happy with a voltage of just 7V out of the battery. Dips below 9V are pretty common towards the end of a match.

The charger might be specifying 11.5V just because that's an expected auto electrical voltage. Maybe buy one of those giant 6V lantern batteries and hook it up to that and see if it still puts out 19.5V? If not you might need a separate DC-DC that can boost 6V up to 12-14V. Which is starting to sound complicated, but I'm not the one who chose a PC that needs a smart pin power supply...


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