Odd PropBoard Behavior

PropBoard
#13

Thanks, Ivan. I went out and bought that battery, only to discover that it’s far larger than a AA or AAA, and the two I’d need won’t fit in my lightsaber along with the other components. I have two options at this point:

  1. I could ask here if there’s some other battery option available that’s more compact.
  2. I could completely overhaul the internal design of my lightsaber.

Obviously, I’d like to start with option #1. I was hoping a 9V battery would do the trick, but as you mentioned, I guess that doesn’t provide a high enough power output. Do you have any other battery recommendations?

#14

Hi @Joecool

You can find Li-ion batteries in 14500 format (that’s AA measure) instead of 18650. Can’t find any website right now able to produce a decent datasheet. If you find one, check if the max. current drain is within the typical current consumption of your circuit (beyond 2A?).

Note also that their voltage is 3.7V and if you use 4 of them with the PropBoard you’ll be over the maximum voltage supported.

#15

That’s great news!! I was starting to think I would have to basically start over.

I’m not sure what my current draw is. (This is my LED. When the lightsaber hit effect activates, I’m guessing I pull maybe a little over 2A for a bit?? Maybe that’s my problem…) However, my circuit initially worked when I used 4 brand new Energizer E92 AAA batteries.

If I were to go strictly off of voltage (which I now know isn’t proper):
AAA battery = 1.5V. Thus, 4 x 1.5V = 6V
14500 battery = 3.7V. Thus, 2 x 3.7V = 7.4V (> 6V)
Therefore, I’d only need two 14500 batteries.

Taking into account current draw:
Let’s assume I’m drawing 2 Amps. I’d need 4 AAA batteries, each discharging 500mA to reach that current. According to the capacity-discharge chart (if I’m reading it right), this means a per-battery capacity of about 450mAh. Thus:
450mAh / 500mA = 0.9 hours.
No wonder my circuit eats AAA batteries like crazy, and I’m getting odd behavior after using it for a while!
(How’d I do with this calculation?)

I’ve found one 14500 battery available at a local store, and here’s the manufacturer’s webpage with the datasheet. (Version LS 14500.) However, it looks like that battery is rated for only up to 100mA of current draw. Am I reading it correctly?

#16

Hi @Joecool

That’s a lithium-thionyl chloride (Li-SOCl2) with a 250mA max (pulsed) current drain. You need a Lithium-Polymer (LiPo) or Lithium-Ion (Li-ion) battery.

#17

Ah, of course. Thanks.

I’m having a difficult time finding Li-Ion datasheets, as well. But I did find this. Would any of them be suitable? PH5 (which I can buy here) looks pretty encouraging to me.

#18

It’s the first time I see a 1.5V Li-ion battery. You may need some special charger for these, I believe.
Worth a try for sure.

#19

Hmm. I was hoping for more of a sure bet. Have you found anything that will for sure work?

#20

I’ve found Energizer Ultimate Lithium AAA batteries:
http://www.energizer.com/batteries/energizer-ultimate-lithium-batteries#aaa

I’m a bit skeptical, since they’re pretty typical off-the-shelf batteries. But they are 1.5V and the datasheet says the max current draw is 1.5Amps per battery. So, if I use 4 of them, I should have no problem, right? (The battery might just not last that long. But as a stop gap, it would be okay?)

#21

Hi @Joecool,

I don’t know Li/FeS2 batteries. If I have to try one of these, I would choose the Li-ion ones.

I always try my best to help, and what’s recommended has been discussed already, but please understand I cannot guarantee for every battery manufacturer or do research for all kind of batteries. For your special case (AAA or AA Li-ion) I can give some advice or opinion, but I can’t tell you to blindly buy something I don’t know or I have not tested. On paper it might work, but what would happen if I tell you to buy those batteries, that at the end are not good enough because [insert unforeseen reason here]?

#22

Oh, absolutely! I totally understand. Electrical engineering just isn’t quite my forte, so I’m just looking for a second set of eyes to make sure I haven’t missed anything obvious. For example, the current draw requirement you mentioned.

I’ll give a few things a try and see what happens. Thanks for the guidance!

#23

Finally getting back to this project after a few months.

I’ve started using two 18650 batteries, 3.6V each. They’ve solved most of the odd behavior I was experiencing. (Hurray!!) There are two problems remaining:

  1. The sound is still quiet and “vibrates”, i.e. cuts in and out at a high rate per second
  2. The board is overheating when I keep the batteries connected.

RE #1: I’ve tried different speakers to no avail, and checked the volume in the program. (It’s set to 7.) No idea what the problem is there. Any suggestions would be helpful.

#2 is almost certainly related to that diode I had to re-solder, because it’s no longer on the board. :sob: (No way to find it either. I’ve moved this project a couple of times in the last couple months, so the part could have fallen anywhere.) Any idea which diode that one is on the schematics? (If I know that, I can refer to the hardware list and possibly find an equivalent replacement.)

#24

Hi @Joecool,

The diode is a BAT60JFILM.

Regarding sound problems:

  1. Are you still using the lightsaber demo, or PBSaber, or a program you wrote?
  2. Can you try with another SD. Perhaps this is too slow to read from.
  3. Has it ever worked? Or it did worked but after the hardware issues it started to sound bad?

About the temperature problem, it’s hard to say what could be. You can check if when you soldered the diode or when it broke, the pads were left joined somehow.

#25

Thanks, Ivan!

  1. I’m using the older lightsaber demo code.
  2. (and 3.) It used to work just fine with the same SD card.

I don’t see any solder where the diode was; I think the pads lifted off with it. (Been looking into PCB pad repair online.)

Here’s a link to a few photos of the board, if that helps. (Apologies for the quality. I don’t own a macro lens. Could get some really close up shots through my work though, if needed.)

#26

Hi @Joecool,

The board is in a pretty bad condition. It may be a shortcircuit somewhere, but at this point I cannot precisely tell what’s going on

Regarding the diode, if the pads were lifted off, I cannot see how you could re-solder it.

#27

Hey Ivan,

There are ways to repair a lifted/removed pad, but it takes specific equipment. Pretty sure my work has this equipment somewhere, so there is some hope.

Yea, I’m not happy with the condition of the board, either. It’s entirely my fault, of course. Soldering over and over again with old solder heads did this. I’ve bought new solder heads to prevent additional damage, and in the future, I’ll solder wire connectors to the board so I don’t end up toasting the thing like I did on this project. Live and learn, I guess. (This was a really good learning experience for me, so that’s something.)

#28

Update: After finding the time to speak with a PCB specialist at my office, I’ve done some work overhauling this thing. The reason the board was so toasted is that I was using a silver solder, which has a high melting temperature. I’m now using a lead solder (in a fume hood) which has a much lower melting point.

I’ve also bought and secured a new diode to replace the one was that ripped off the board. (The PCB specialist helped me make a new connecting terminal! :slight_smile:)

As for the problems I was having, I disconnected the LEDs to make sure they weren’t causing any problems, and secured screw terminals to the board to prevent further heat damage. I’ve also replaced the speaker and wires connecting to it.

Here’s a video showing the audio problem I’m having. I’m using the audio files recommended in the tutorial (the ones here). As I mentioned previously, the sound “vibrates” and is quiet. The current speaker is Digikey p/n 433-1147-ND, though I’ve tried a few others as well that I bought for this project.

Things I’ve tried:
-Replacing the speaker and wires (currently 24 AWG multi-strand wires)
-Replacing the audio files
-Changing the audio volume in the program
-Disconnecting the LEDs (to prevent excess power drain from the two 18650 3.6V batteries)
-Resoldering speaker / wire connections
-Resoldering the screw terminals to the speaker
-Resoldering the screw terminals to the batteries

Any ideas what might be happening?

#29

Hi @Joecool,

Thank you for posting the video.
A PropBoard sounding like that is something we haven’t seen before. Probably a damaged codec or amplifier, o some of the passive components around them. It’s really difficult to diagnose it. If you feel like, you can replace the amp first and then the codec, but they are such tiny components (specially the amp) that’s probably quite difficult to do it without the right tools.

#30

Thanks, Ivan! I looked at the amp under a microscope at my office, and it looks fine–no visible damage to any of the pins coming off of it, or to the ‘box’ itself. Here’s a picture of it. (I’m not sure where the white scratches to the upper left came from, but they’re only surface-level. I examined it from multiple angles.)

Is the “codec” the component identified in the schematics as “U3” and “WM8523GEDT”? If so, I don’t have a pic of it yet (I can get one if it’ll help!), though it looks fine to the naked eye, at least.

Could the problems be inside the black casing of the components, hidden from view? (If that’s the case, I can definitely give it a try to buy replacement parts.)

#31

Yes.

Yes, and this is mostly what could be happening, or some passive component around them (like capacitors, etc.).

Would be difficult to diagnose without an oscilloscope and some knowledge on general electronics. I can’t assure you that changing components will bring back the board.

Firmware Version
#32

Sorry to raise a thread from the dead, but wanted to give an update in case that sheds new light onto the Propboard behavior:

  1. I’ve added a “master kill switch” to my circuitry to prevent any overheating problems. It’s a switch in series with the positive lead of the battery. Works like a charm. :slight_smile:
  2. The “vibration” sound problem somehow seems to have solved itself, but the sound is still very quiet. I’ve tried several settings for the setVolume function in the program, going from 1 to 30, but it appears to make no difference.

Otherwise, the thing works perfectly: Lights, accelerometer, all buttons. My program works! :smile:

If you have any insight into issue #2, let me know. Otherwise, thanks for all the help!