I'm building a wireless controlled robot with a tank kit and a dual motor gearbox. I'm controlling the motors with a l298 and an atmega32 micocontroller.The problem is that when i turn on the motors they probably cause a dip in the power and that makes the atmega32 turn off. The statusled which goes on when the wireless connection is started goed off. I wish i had a scope or something so i could check this. With my multimeter i could not detect much, the voltage dropped from 6 to 5.8 volts. I used 4 alkaline 1.5v AA batteries.
I had this problem before when i had the motordriver on a prototyping board. but i fixed it with a ld1117 those can only handle about 800mA. But also without the ld1117 the atmega32 turns off.
I think this are the options:
batteries can't give enough power, all power goes to motors, micocontroller stops
design problem
other...
Does anyone knows what the problem could be? i've attached my schematics.
put a fairly big cap between power and ground near the motors, it sounds like a decoupling problem. This cap will provide power during the surge when the motors first turn on.
I collect any old (or new!) electronics that are about to get tossed. I got two motherboards a while back and just decided to take all the parts off of one of them. I found nearly 20,000uF of caps on there! Mind you, some of them were only rated up to 6.3v so I won’t use them for 5v systems but I would suggest scrounging around a bit for some old electronics if you can. 20,000uF is enough to power a Picaxe 08M for days in low power mode!
I thought it was working with the electrolytic capacitor but when the tracks where on there was a higher current so it still stopped. I made a ld1117 between the power supply and the atmega and the capacitor behind it that should work but no. And just before posting a new question i read your post again and especially the part with “Check that it still works with a voltage drop of 800mV”. I than remembered something about the ld1117, it need a supply current at least 1v higher. And i was going from 6 to 5v so with a voltage drop it would not work.
