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Bescor MP-101 camera pan/tilt head with Arduino question

ElectroTonic

Apr 18, 2014
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Apr 18, 2014
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Hello, I'm trying to figure out the best way to control a Bescor MP-101 camera head with an arduino. I want to use PWM to control the speed of each axis.

The head comes with a controller that you can use to manually rotate the unit left and right as well as manually tilt up and down. The controller plugs into a the unit via a 7-pin midi jack.

I have made a cord that plugs into the midi port and breaks out 5 of the 7 pins because these are the only ones necessary to make it move in all directions. I have figured out each wire's role by touching each together and using a multimeter. One of the wires is a common V+ at 6 volts and the other 4 are for each direction

The confusion comes when trying to hook it up to the arduino. I have used transistors for switches in the past but only with common ground. Since I cannot just attach the 6 volt wire to the arduino's V+, I don't know how to hook this up. I feel like this is a simple problem but I just can't wrap my head around it.

One solution I think would work is to use opto-isolators instead of simple transistors but I would like to use transistors because I have a bunch of them but I don't own any opto-isolators.
 
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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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If you make the +6v of the controller common wiith the +5V of the arduibo power supply (remembering to keep the grounds separate, then 4 arduino outputs can drive the bases of 4 PNP transistors via a (say 1k) resistor. Their emitters are all connected to the common +5/+6V and their collectors connect to the 4 other control wires.

Because this is inverted, the arduino outputs have to be normally maintained in a high (on) state to keep the transistors off, with one (presumably) taken low at a time to tilt/pan the head.
 

ElectroTonic

Apr 18, 2014
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Apr 18, 2014
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Thank you so much, that makes sense, without the grounds connected there is no danger of putting current into the arduino from the power supply of the pan/tilt head. I'll try it out.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Excellent!
 

jmarisa

Jul 7, 2021
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Thank you so much, that makes sense, without the grounds connected there is no danger of putting current into the arduino from the power supply of the pan/tilt head. I'll try it out.
Do you have a picture of how you were able to set this up?
 
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