Power issue with board?

jemartin144 · Post by **jemartin144** » Sun Jun 15, 2014 4:02 am

All of the sudden by board seems to be having a problem with getting power from my 12v input. When connected to the 12v my power light blinks and flashes and dims in no particular pattern. The board sort of works when in this state. It will log to the SD card sometimes. I can plug in into the pc and the light still blinks, but I can talk to it. I've tried flash the firmware a few times.

When i look at the 12v on a scope when hooked up it has a like .5v waviness to the trace.

None of the components on the board look particularly bad. The 336D Cap (C41) over on the power side looks a little darker on the + side, so maybe its that? Ill try to get a picture, but its tough cause its all so small and only have my camera phone.

This is really frustrating. I finally got all my sensors hooked up and was getting things to actually start working.

An ideas?

jemartin144 · Post by **jemartin144** » Sun Jun 15, 2014 7:35 am

So, I found the schematic for the board and had a poke around. It looks like the 5v and 3v supply is spot on. There must be something else wrong. Either on 12v or the USB power the power light flashes erratically and all sorts of weird things are happening within the logging. I can communicate with it over usb, though.

i dont know...

jemartin144 · Post by **jemartin144** » Tue Jun 17, 2014 6:25 am

well, i have an update. looks like the power led has failed. I can touch an external led to the bottom pins and it reacts as expected (Solid on with power). I'm not sure if this is a cause or a symptom. I probed around a punch and everything that is labeled 5v on the schematics seems to be getting 5v fine. I'm going to take a stab at replacing the led and see if it effects the troubles I'm having with it not logging correctly.

Incidentely, I did try going back to a slightly older firmware, with no change in results.

I have attached a sample of what a quick log looks like after installing 1.2.6 and not changing any settings.

jemartin144 · Post by **jemartin144** » Wed Jun 18, 2014 5:09 am

Well, replaced the power status led and that is functional again. The data files still seem to weird. I'll update when i get a chance to play with it some more.

Post by **brentp** » Sat Jun 28, 2014 5:38 pm

Hi,

Sorry you had to deal with the LED; that seems very unusual.

Can you describe your problem with the data files? The file format is sparsely populated CSV, which may confuse some.

jemartin144 · Post by **jemartin144** » Sat Jun 28, 2014 8:18 pm

I agree the led failure was weird. I don't really know what was going on there.

So, I think I mostly figured out what was going on. I was setting up a potentiometer based steering sensor. I was using a 10 turn pot which is way more than the 3 turns the steering wheel does, so when I did the scaling map for the sensor it was very narrow. So, if I plugged in the usb without the car on and starting logging the voltage was halved and outside of the range on the map and it was crashing the box. I have to reflash the firmware whenever this happens. This seems to happen anytime a sensor's voltage is outside of the scaling map.

Basically, never log without 12v attached if you have scaling setup.

In the end I got everything working for my race last weekend. I got good data, which is great.

Post by **brentp** » Sat Jun 28, 2014 11:05 pm

Hi, Glad you got it working. are you supplying 5v to the potentiometer with your installation?