Some problems building my first bluesaab (5.1)

[Faran]

Hello everybody

The problem i am having is that when i plugged in the bluesaab to my arduino uno to write the bootloader i had stable light on power and blinking light on both bt1 and bt2. But the lights suddenly stopped after a few minutes and now when i replug the bluesaab i sometimes get a very weak light on the power led for a few seconds.

So i am thinking that a solder point is bad or something, anyone got any clue?
Something more i just noticed is that the board gets really hot around U6 and the left ish part of the card.

And for the software part i am following this guide ArduinoISP for the bootloader part, but i am unsure if it will work..

Thanks!

[homerisback]

I had the same kind of issue with Arduino Uno only powered by USB ; I mesured the voltages on the board and hadn't more than 2.9V which is to low to power steadily the RN52. USB voltage from my PC motherboard was too low : around 4,75V instead of 5V.
U6 chip needs a minimum voltage to provide a good 3.3V to the whole board (5V mini if I remember well).

The best would to power the arduino board with an additionnal DC power supply (recommended 7 to 12V), it should be ok then.
I suggest to follow this web page to connect the Aduino Uno to the BlueSAAB ISP. Upload ArduinoISP sketch to Arduino Uno board, then burn bootloader and upload SAAB-CDC code using "Arduino as ISP" under Tools>Programmer menu.

Good luck, that's an amazing device !

[Seth]

If the vreg is getting hot, it's prob because something is drawing too much current, which could easily be because of a short. Check everything; 3.3v goes to all components.

USB power should be fine, but make sure you're using a good quality cable; I've actually had issues with a micro USB cable that just can't power anything (BlueSaab uses mini USB).

If you can use a power supply to power it you'll be able to see how much current the module is drawing; it shouldn't be more than 100-125mA(?).  If it is, then you def have something wrong.

[Karlis]

I had this sort of thing (both BT LEDs blinking a couple of times and then shutting off) a number of times. I learned the hard way to check, double check and then check once more the orientation of the power diodes. Many times I used the wrong diodes and RN52 chip was chocking up not receiving enough juice. I'm sure this is not your case.

Long story short, I'd start with checking the orientation of diodes and then for shorts on the board. Particularly on ATMEGA-328 and FTDI chips. The gap between pins on those is really close and one has to be really precise in getting them soldered to the PCB. I'd also check for shorts on the vertical USB connector. This might not be of importance, but... well I've built around 50 modules now and have seen all sorts of weird stuff. :)

Good luck!

[Faran]

Thanks for the help pointing out possible faults guys!

I had to go out and buy a new multimeter because my old one was going crazy when i measured resistence (chinese POS )

So now after measuring it seems like i have a short between power and ground on the upload socket and the ISP header. And it looks like the resistence is lower on the upload socket compared to the ISP header.

So it seems like im going back to the bench to troubleshoot some more. But im thinking about ordering another set of components either way because when i was working with "U7" it decided that it was a good idea to fly away from my tweezers grip, and now i can't seem to find it