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Controlling a 12v 80 watt dc motor with an Arduino

Pommie

Well-Known Member
Most Helpful Member
To divide the battery voltage down you need two resistors. Resistor 1 needs to be twice the value of resistor two - say 20k and 10k. You connect the 20k to 12V the 10k to Gnd and join the free ends. Where they join goes to an analogue in pin. You could of course substitute the 20k resistor with two 10k resistors in series.

Mike.
 

dr pepper

Well-Known Member
Most Helpful Member
The purple wire wont work on that pin, you need to connect it to one of the 'duino's Pwm pins, the pins that have a ~ symbol are Pwm pins, pin 3 is a good one to use.
Another thing I spotted you have the motor connected to motor2 terminals, the way the module is connected you need to wire the motor to motor1 terminals.
 
Does this look about right so far? I was looking up the resistors what watt should i get I've found a 10k olm resistors go as low to 1/2 watt all the way up to a 10 watt ... what do you think is best?
 
Ok hows that and what would be next in your opinion.Would these work (Resistor Carbon Film 10k Ohm 1 Watt 5%) and (Resistor Carbon Film 20K Ohm 1 Watt 5%)
 

ChrisP58

Well-Known Member
The actual power dissipated in the 20K resistor will be less than 5 milliWatts. And even less in the 10K resistor.

1/4 Watt resistors would be fine. 5% carbon film would be ok, but my choice would be 1% metal film.
 

dr pepper

Well-Known Member
Most Helpful Member
I think you got it.
Dont forget a heatsink for the transistors on the H bridge board, the trannies at the bottom looking at the pic need sinking.
The devices need to be electrically insulated from each other with washers & bushes.
You can buy a ready made sink or use some ally plate.
 
ok i was hoping to put it all in a old car amp housing with a cooling fan also on the H bridge board what do you think or would the fan not be needed for extra cooling
 

dr pepper

Well-Known Member
Most Helpful Member
Depend son the load on the motor, the sink on its own might be enough but a fan cant hurt.
The 'duino shouldnt need a sink, monitor the regulator next to the power in socket, if it gets hot the best way to deal with it is to put a seperate 5v reg on the ally housing, but that shouldnt be required.
 

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