Hi guys, I am a beginner in arduino and robotics. Recently I am starting a project for a 12DoF hexapod. I am controlling the servos(Tower pro micro servo SG90) using a TLC5940 based on this schematic by John Boxall:
From the schematic,I changed the LEDs to servos and attached a 2.2kOhms resistor between every output and the external voltage(in my case external voltage is from 4x1.5V AA battery)
Also from my DMM(el cheapo,might not be realiable) reading I get about 20mA per servo under no load,which I measure between the output to the external voltage. Any solution on how to get rid of the jitters are welcome,BTW,they are working fine if I only run not more than 3-4 servos simultaneously.
You are using the schematic that was driving LEDs. A typical current limit for LEDs is 20mA. The IREF resistor is likely what is limiting current. I would not suggest removing it completely. You should probably do some more research on using this chip to drive servos.
Stupid question time. You are feeding the outputs to the signal wire on the servos, right?
The other comments re: more power are spot on though. If you are going to drive 12 servos at once, you should account for at least .5A per servo or 6A minimum.
