Arduino program doesn't upload and start code

Hey

I am making a line follower robot. I'm using Arduino Nano and it doesn't upload code if it is in circuit. If I take the Nano out from female headers on the board, it uploads and starts the sketch, so Arduino is not the problem. The error I get when Arduino is on the robot is: avrdude: stk500_recv(): programmer is not responding I suspect that it's a power problem but I couldn't have solved it myself yet. According to multimeter measurements, there should be no short circuits. I am powering Arduino directly from 2s LiPo battery and the motors get power from: http://www.ebay.com/itm/2PCS-Supper-mini-3A-DC-DC-Converter-Step-Down-buck-Power-Supply-Module-3V-5V-16V-/310929959685?hash=item4864deab05:g:YHcAAOSwtnpXiebU These two power modules are connected parallel to get enough current. If I disconnect the modules from the circuit then nothing changes (the problem stays the same). What could be the problem? If you need any more information, please don't hesitate to ask.

Mikk

I suspect that it's a power problem

It is NOT. You clearly have something connected to the hardware serial pins that is interfering with the upload process. That is clear, since the upload works successfully when nothing is connected.

I already checked it with multimeter and there is nothing connected to serial pins.

Hi, We need to see your schematic and code, to see just what pins you are using and what is coded. But like PaulS says, you must be using D0-D1 for somethnig else!! Check again. Where do the modules gat their power from??

hope it helps, regards

Mel.

Schematic Protoboard bottom Protoboard top

The modules get the power directly from battery. ESC is for a suction fan. I have a connector for bluetooth module but I am not using it yet.

I had a bad capacitor in parallel with the battery. I soldered it out and everything works perfectly now.