Problems with IR Board

[Mark McLeod]

IFI isn't in the production or supply loop on this IR board yet.

For technical assistance I'd talk to Ben Wrightsman at Diversified Systems Inc. the manufacturers of the board.

For a replacement we'll probably have to go through FIRST.
I have a message in to FIRST and will let you know what I discover.

So far the reported failures are quite small in regards to the 1500+ boards produced, so I'm hopeful it's a less than 1% failure rate. Ben told me they sampled boards coming off the production line and the samples all passed, but not every board was tested due to the time constraints of the Christmas rush.

P.S. Based on keen101's experience it does sound as though teams should run these for some time to make sure they catch any marginal failures early.

[keen101]

as far as how mine died... It shall probably always be a mystery.

Maybe something shorted, but I think overheating is more likely. I had been playing with it for over an hour. Enough time to overheat?

Besides... I didn't think anything could short out on an anti-static bag. Who knows, maybe my finger slipped and shorted something. seems dubious though.

[MrForbes]

beeing over 40, I had to take a picture of the part to be able to read the writing on it!

[Alan Anderson]

Originally Posted by keen101

Besides... I didn't think anything could short out on an anti-static bag.

That turns out not to be the case.

An "anti-static bag" is conductive. It protects against static electricity building up on the bag itself and then zapping something inside it. But exactly because it is conductive, putting a device on top of it is almost like putting a device on a piece of metal. Even if it doesn't short itself out just by sitting there, you can very easily zap it by touching it and having the current flow through the bag to ground.

[keen101]

oh. ...So it probably was me.


Thanks for the info. I did not know that.

I shall be more careful in the future.

[Elgin Clock]

Originally Posted by Alan Anderson

That turns out not to be the case.

An "anti-static bag" is conductive. It protects against static electricity building up on the bag itself and then zapping something inside it. But exactly because it is conductive, putting a device on top of it is almost like putting a device on a piece of metal. Even if it doesn't short itself out just by sitting there, you can very easily zap it by touching it and having the current flow through the bag to ground.

I would think that FIRST would have put a warning on the datasheet announcing something like this if it were something they expected us to be handling a lot. Not every team has a trained electonics Mentor, and something like this could indeed be looked over if you weren't trained in how to handle circuit boards.

I'm even hesitant in testing this, or doing anything with it till we get the full aspect of what it's used for, but maybe that's just because I've broken a ton of FIRST related parts from the kit in the past and it's my forced cautious nature taking over me now.

[billbo911]

Originally Posted by Kevin Sevcik

I'm thinking this might be an oversight in the circuit design. The 78L05 series of regulators are rated for 100mA max output current. And the IR manual claims the circuit draws 100mA when an LED is on.

I can't say I agree with this. Here is a quote from the IR board users manual:

When a single LED is on, the current should increase to approximately 19 mA.

It also says:

With a single LED on, the power consumption will increase to approximately 228mW.

Which at 12vdc: (228mW/12vdc) = 19mA.
So at least they agree. My guess is that it is not a design flaw, but more likely a user error. (Sorry, I don't mean to point fingers.) I believe it is more likely the board shorted on something, whether it was one of the output wires or the back board. Either way, replacing the regulator "should" resolve the issue.
So far, I have only read about 2 or 3 boards failing, each time it appears to be the regulator. I'm not ready to jump to any conclusions yet. Let's see if a more consistent pattern develops.

[MrForbes]

the board runs at 5 volts, not 12 volts, so 228 / 5 = 46 mA

I put an ohmmeter on a handy anti-static bag, it said infinite resistance....but it's not a very good ohmmeter.

I found the wrappings for the IR board, the same ohmmeter says infinite.

Maybe I'll have to fire up my old Fluke nixie DMM, or go out to the shop and get my old 77....

[www.divsys.com]

As an fyi the Part is
NATIONAL SEMICONDUCTOR
LM78L05ACZ-TO92 IC
VOLTAGE REGULATOR Package TO-92

***I would highly advise not to modify/rework and part of this board before contacting FIRST***

We are working with the group at FIRST and will advise.

thanks,
BMW

[ChuckDickerson]

Originally Posted by Kevin Sevcik

You could measure across pins 2 and 3 of the big whit connector with negative on 3 to check as well.

Anyone have an opinion as to if it would be advisable or not to bypass the regulator and apply a regulated 5VDC to pins 2 & 3 of the white connector to test the remainder of the board?

BTW: Our board was sitting on the anti-static envelope as well when we first powered it up. I have always done such and never knew that to be a problem. If that was the cause then I guess it was my fault. Never knew that to be a problem but I will never do it again, that's for sure. I have emailed Ben at Diversified Systems inquiring about obtaining a repair or replacement. I will post what I find out when I hear back from Ben.

Edit: Thanks Ben. It looks like you beat me to the post!

[Team 562]

Team 562 has no problems with the IR board. In fact, everything has worked smoothly. We trained it to recognize a Sanyo remote control and also hooked it up to a 2004 controller's digital inputs just to see if we could recognize the boards output. It worked fine. I assume there will be a field element that will transmit 4 different codes for some reason and the robot will need to detect the different codes and perform actions based on the different signals?

[www.divsys.com]

Originally Posted by Alan Anderson

That turns out not to be the case.

An "anti-static bag" is conductive. It protects against static electricity building up on the bag itself and then zapping something inside it. But exactly because it is conductive, putting a device on top of it is almost like putting a device on a piece of metal. Even if it doesn't short itself out just by sitting there, you can very easily zap it by touching it and having the current flow through the bag to ground.

Incorrect, the bags are a faraday cage protection. Static shielding bags protect against static charge from both inside and outside. You could only harm a part by inducing static charge to it once removed from the bag.

As far as powering the part while on the bag that would be a bad idea. The aluminum layer sandwiched between the two poly layers could possibly cause an issue if the parts leads dug into the bag. We have seen failures caused by this.

BMW

[T3_1565]

Originally Posted by www.divsys.com

Incorrect, the bags are a faraday cage protection. Static shielding bags protect against static charge from both inside and outside. You could only harm a part by inducing static charge to it once removed from the bag.

BMW

Good to know, I will know place my board back on the package lol.

Our board has been working fine since we got it (and still works fine thankfully) How long did you guys work with it, as I have only had it on for 15 minutes at a time. then I come back on here and post interesting things I have found (like the double remote problem!)

[Kevin Sevcik]

Originally Posted by DeepWater

Anyone have an opinion as to if it would be advisable or not to bypass the regulator and apply a regulated 5VDC to pins 2 & 3 of the white connector to test the remainder of the board?

BTW: Our board was sitting on the anti-static envelope as well when we first powered it up. I have always done such and never knew that to be a problem. If that was the cause then I guess it was my fault. Never knew that to be a problem but I will never do it again, that's for sure. I have emailed Ben at Diversified Systems inquiring about obtaining a repair or replacement. I will post what I find out when I hear back from Ben.

Edit: Thanks Ben. It looks like you beat me to the post!

If the 12V input were grounded somewhere I think this would be a bad idea. However, since the only ground path available to it is through a capacitor, I don't think it would make anything explode. and since your regulator's apparently dead anyways I don't know that saving it from anything matters much now unless FIRST or Divsys are planning some forensics on it.

[Elgin Clock]

Originally Posted by www.divsys.com

***I would highly advise not to modify/rework and part of this board before contacting FIRST***

/me Can just see the invisible writing on the typical electronics field wall.
"Opening this case (ie: playing with the components of the board) voids all warranty"
Oops. LOL

Thanks for keeping in contact with all of us about some problems/concerns raised with the board Ben. I'm guessing we are the "guinea pigs" for this board, so heavy use probably can (and will) find something that representative testing of the boards off the assembly line unfortunately would not.
It's just the way it is.


Welcome to the wonderful (and most times hectic) world of being a first sponsor/supplier.
Good luck in the next 4 months keeping your sanity. LOL