Mini Maestro 12, Servos, LEDs and PIR Sensors Question

I have a question about attaching components other than servos to the Pololu Mini Maestro 12, and am hoping that someone can answer them for me. First of all, I am currently using a 6V 3A DC adapter to power my board and run 8 servos. On top of this, I would like to add 20, 5 mm LEDs on 2 different channels (10 per channel), and 2 PIR sensors on the remaining 2 channels (1 per channel). The sensors have a ground, power, and output wire, and have a working range of 4.5-20V. After reading page 7.b. Attaching Servos and Peripherals in the Maestro User Guide, I was able to successfully wire one sensor to the board. As I move forward with my project however, I see that I will probably need to use a larger power source than what I have running through the board. My question is, is it possible for me to wire my LEDs and PIR sensors to a seperate DC adapter and only have the signal wire running to the Maestro? If not, then is there some way that I can accomplish what I am trying to do?

Thank you in advance for your help!


Yes, you can power your servos and peripherals separately from the Maestro. In addition to your signal lines, you will need to be sure you have a common ground.


Great, I appreciate your response! I went ahead and connected one of my PIR sensors to an external power source (12V 2A DC); with power running through a 10k resistor, output running directly to the Maestro (channel 1), and ground running to ground on channel 1, as well as ground on the power supply. While the sensor works fine with the board, any channel that I enable as an input is now mirroring the signal from channel 1. Do you know why this is happening? Also, do you have a recommendation for how to connect multiple (roughly 10 per channel) LEDs to the Maestro with an external power source, noting the current limits on the signal line? Thank you again for the help!

Do you have any other sensors connected? If not, we expect those other channels to be floating and their voltage to follow the connected sensor. Can you try connecting your other sensors and see if that helps? If it does not, please post a proposed wiring diagram of your system that shows how you connected the sensors and your Maestro settings file. You can save the Maestro settings file by selecting the “Save Settings File…” option from within the “File” drop-down menu in the Maestro Control Center.

You could use a MOSFET to switch the power for those LEDs, but if you want easier connections, you might consider one of our RC switches.


Thank you so much Derrill. You were right about the floating channel. I haven’t gotten around to trying the MOSFET yet, but when I do, I will respond here.