Bescor MP-101 and Arduino v2.1

New code here v2.4

On v2, I didn’t assign all the directional wires PWM pins, and it caused me to use the purple wire as speed which was unnecessary.  In v2.1 the speed and direction come from the direction wires.  Also, I learned from this link the Bescor goes to ground at limit which means it will stop moving overtime when it goes in two directions.  By using 1.5k resistors on each end of the four wires, the Bescor doesn’t reach the ground limit.

White = up

Blue = down

Yellow = left

Green = right

White = pin 10

Blue = pin 9

Yellow = pin 11

Green = pin 3

The Bescor had a lot of electrical noise, so I changed the PWM frequency using this code.




  1. Sorry if this is a dumb question as I am new at this type of thing, but do the resistors slow down the motor speed at all? And if so, would a lower resistance still work?

    • Yes, a resistor can slow down the motor by limiting the amount of current flowing through it, but it also reduces the torque. I don’t know the proper resistance for these motors, but you could try to use a variable resistor which allows you to adjust the current at varying resistances.

  2. Hi Matt,

    Why do you use direct power to steer the motors, think when you add transistors over the switching wires you can switch these with pwm so you dont have to send current up to the motors.

    I have still check this on the bescor but it worked like this on normal remote controls to make them switch, i use bc 547b with on the base 200k to pwm, collector to ground and switch wire to emitter.

    Power on base and the switch goes on.

    Greetz Richie

    • I don’t have a lot of knowledge on remote controllers, but I love to tinker. Working with the Arduino has taught me a lot. The original Bescor controls are setup in an awkward way, and I would like to try anything to improve it. The method I was using probably isn’t the best, but at the time it was one solution.

  3. Hi Matt, no offence iam a thinker and search for solutions like you it was only to give you and others another way to switch without sending power up the machine bit safer maybe 🙂 i readed its switch to ground so thats my thinking adding to your solution. Greetz Richie

    • Thank you Richie, I want to try using transistors like you suggested. I’ll put in a order this week and see how it goes when the parts come in.

  4. Your welcome, i also build a pan tilt from scratch with at first 2 servos now i have removed the pan servo because the angle was not wide enough 45 degr. i did put in a stepper motor and its goes 330 degr now only need some fine tuning. Only developing costs me a yr so i did buy a bescor so i dont have to make a new one myself.

    Try the transistors and i think its precise what you want .

    Thanks for your time

    GreetZ Richie

  5. Hi Matt,

    I did make the switching transistors like mentioned before and it works the only thing whas the wires are strange colored, further i added a 5v lm 7805 to feed my bareduino and i want to make it wirreles 2.4ghz all parts laying around need only time to build it.

    Greetz Richie

  6. Hi,

    I was wondering which inputs the nunchuck wires go into, when you not using the Ardunion shield, it diagram just seems to show where the midi-cable inputs go?



    • I’m going to make a new tutorial using the Nunchuck. Here’s how it’s connected to the Arduino, but it doesn’t directly connect to the Bescor.

      Yellow – A5
      Green – A4
      White – GND
      Red – 3.3v

      or you can use an adapter like this one.


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