ok… so like 10 minutes before we had to pack the robot up for shipment, the students were pushing the robot across the floor (generating that slight amount of current) which fried all 4 of our IR boards… so i took all 4 of them off, and shipped without them…
in the mean time ive been working on them… the voltage regulator had melted leads (which made sense), so i replaced them today, and the board is still not responding.
I have tested all the resistors and capacitors on the board and nothing seems to be faulty. The board itself creates a complete circuit, but when i apply power the board is unresponsive. No error light, and the program button does nothing.
The only thing i believe it could be is the PIC. Might it need reprogramming? replacing?
has anybody else had this problem? or could maybe shead some light on the situation
Thank you for your time in advance
-Joshua M. Stilwell
Electronics Mentor
Team 1254
I think you may have nailed the source of the board failures. Unless a switch has been placed in line with the IR board to open the +12 supplied to it, (as suggested in Team Update #10) pushing the robot will generate power to the board at various voltages. When that voltage is in the ~ 3vdc range, it can corrupt the programming.
There are a couple options:
It can be reprogrammed at the regionals. They will be using a modified version that protects the code from being corrupted by low voltage.
You can get rid of the IR board entirely and just use a single Vishay IR sensor. Add Kevin Watson’s IR code. It will take all of 20 minutes to do this if you have the sensor. (Hint: there were several in the 2004 KOP).
All the details for this can be found in this thread.
so FIRST will be reprogramming the boards at regionals?
should i replace the rest of the voltage regulators? or are then not actually the problem, just the code…
cause the boards are melted slightly around where the regulators are… which i supposed a continuity test would tell… anyway, should i worry about it?
PS. i had the switch and everything, i was about half way done installing it, and needed to test them again so i just plugged it back in, and forgot to finish the job
The lead inspectors will have the ability to reprogram but if you had a regulator failure, reprogramming might not fix the problem. The designer gives the user the ability to remove the regulator and connect the board to +5 volts rather then the 7.2-12 volts with the regulator in place. During reprogramming the power is delivered through the USB port on the computer. A lead inspector will examine your board prior to reprogramming to check for issues that affect power supply.