Connecting Switches to 6-Channel Maestro

Support Servo controllers and servos
1

Hi, I need to connect three servos and three microswitches to my 6-channel Maestro.

The board is powered via USB. The servos are powered from a regulated 5V supply.

In order to make things easy to construct and maintain I would like to connect each microswitch using a three-pin connector. I.e. use signal, +ve and -ve from a single servo connector for the microswitch, connecting a 1k - 100k resistor between servo +ve and servo signal.

I’ve read on this forum that it is not a problem to connect any 5V supply to an input pin on the Maestro. So can I use my servo 5V supply for switches? I will be polling a switch while a continuous rotation servo is moving.

Thanks, Andy

2

It is not a good idea to use the motor power supply as a source of 5V for input switches unless it is very carefully filtered. Electrical noise caused by the motors would likely result in false input signals.

3

Hi Jim,

Thanks for replying. I presume I would be able to filter them in software. It’s good to know I won’t damage the servo controller itself.

Andy

4

I meant an electrical filter – a simple RC “low pass” filter should eliminate most noise problems. If you are not familiar with the concept, google for examples. I suggest to connect a 100 or 220 ohm resistor to the motor supply, followed by a ~ 220 microfarad capacitor to ground (values are not critical, but observe the proper polarity for the capacitor). The junction between the two is the source of filtered +5 V for the switches.