Hi, I am new to arduino and not very advanced in electronics. I have an 18V DC motor from a battery driven power drill which still is connected to all the electronics such as IRFZ44N (Transistor N Channel MOSFET) and a 14069U (Inverter 6-Element CMOS 14-Pin). The 14069U has a sliding potentiometer which ranges from ~1.7Kohm to 480Kohm. I would like to use the arduino to physically emulate that potentiometer in same range of ~1.7Kohm to 480Kohm. Preferably slowing the motor even more down by going higher than 480Kohm. The fast RPM by means of the 1.7Kohm is not of interest to me.
Could I please be pointed in the right direction how to connect and program the Arduino?
Thank you Andreas
You need what is known as a digital pot, google
Arduino digital pot
For examples. I am not too sure they do a 500K one though and most pots can't Handel 18V.
But you might find some that will.
Microchip makes digipots that handle up to 36 volts. I used one to hack a dcdc converter so it was digitally controlled, for the hell of it.
Check how much voltage it actually puts through the pot - maybe you'll be lucky and they pull only put 5 on it
Thanks for your help. I ordered a MCP41100 100k Digi Pot and am going to use it with a 400K resistor sequential as I am only interested in the 400 to 500 k range. And yes there are only going 5V DC through and about 1.5 amps. The whole thing is to be for an extruder to make plastic filament for a 3d Printer. I wanted to save money on a strong stepper motor which drives the auger to push the plastic into the hotend.
And yes there are only going 5V DC through and about 1.5 amps.
Ah!
Check the data sheet but 1.5A sounds way over what a digital pot can take.
That pot has only 1mA wiper current.
The whole thing is to be for an extruder to make plastic filament for a 3d Printer.
That sort of thing is normally controlled with a PWM signal and a big FET.
Hustermouse:
Thanks for your help. I ordered a MCP41100 100k Digi Pot and am going to use it with a 400K resistor sequential as I am only interested in the 400 to 500 k range. And yes there are only going 5V DC through and about 1.5 amps.
Where is the 1.5 amps? You are not going to get 1.5 amps through 400 to 500 kΩ.
Archibald:
Where is the 1.5 amps? You are not going to get 1.5 amps through 400 to 500 kΩ.
Not without applying 600 to 750 V!
Russell.
Where is the 1.5 amps? You are not going to get 1.5 amps through 400 to 500 kΩ.
Not without applying 600 to 750 V!
I think that takes us back to :
I am new to arduino and not very advanced in electronics
Clearly he's not actually expecting 1.5 amps to go through the pot, since he seems to know he needs 400k-500k ohm resistance.... I have to assume that the pot is used to control something else that in turn controls the 1.5A load....
It might be nice if he'd tell us a bit more about what he's controlling.
russellz:
Not without applying 600 to 750 V!Russell.
No, those are k ohms, not ohms. , you'd need to apply over half a million volts to make 1.5A go through a 400k ohm resistor, and it would pull close to a megawatt.
That would be a nice Arduino project.
Looking forward to seeing the finished project in the gallery.
Make sure there are some nice pictures.
Thanks for all your input! I mentioned i am not a pro in electronics and/or Arduino.
Before I was able to advance it happened that the flimsy sliding potentiometer fell apart. To continue I have two options:
-
Somebody of you might help me on the way to use the 18V power drill motor to be regulated via voltage change, controlled by the arduino.
-
I just get a strong stepper motor and do it with the Arduino mega + marlin board + stepper driver as I have on my 3d Prusa i3. Just would need a Arduino program for it.
I just thought I save some money with using what I have.
Back to the amps:
- I adjusted my power supply to 18V and turned the amp button a bit up (didn't display how much)
- disconnected everything from the power drill motor
- connected minus from power supply to black cable on motor.
- connected Fluke 17B's black line to the power supply plus connection
- connected Fluke 17B's other end of black line to black GND on power supply
- connected Fluke 17B's red line to white cable on motor
- connected Fluke 17B's other end of red line to red "amp" (not "mA/uA") connection in the Fluke 17B
- Adjusted Fluke 17B to "Auto Range" setting
Result: at start of motor or trying to stall it by hand it shows 3.6A (not mA) in "Auto Range" setting
the amps then go down to a regular 1.6A (not mA)
Thanks
Andreas
He simples way to control the motor is to have a power FET in seriese with the motor and feed the gate with a PWM signal from the Arduino. There are plenty of tutorials about to do that.