Muscle therapy dial control

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monkncheese
 
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Muscle therapy dial control

Post by monkncheese »

I have a muscle electro therapy device that's controlled by a dial, a potentiometer. I want to control it with a Raspberry Pi connected to my PC with SSH. The dial has an intensity range of 0 to 10 mA or higher. I need the digital version of the potentiometer with a wiper of 100k Ohms or more, which is out of range of the Adafruit DS3502.

I don't think I can increase the wiper resistance, is there a device that could read the RL, RW, RH from the DS3502 and convert it into a higher amperage?

Alternatively, I've searched for digital potentiometers with that range of resistance but the ones on boards are backordered for too long. There are also black electronic components with metal pins on them that are called potentiometers. I'm guessing these are used for fabricating boards. Could I use these somehow?

I am also completely open to taking a different approach, any suggestions are welcome.

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barshatriplee
 
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Re: Muscle therapy dial control

Post by barshatriplee »

You can consider MCP41100 or MCP42100 instead. Those are 100K.

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jps2000
 
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Re: Muscle therapy dial control

Post by jps2000 »

For good reason such medical devices are battery operated or use a very special medical grade power supply.
What you may do is to use a cheap RC servo to turn the original potmeter. These servos need just a PWM

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monkncheese
 
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Re: Muscle therapy dial control

Post by monkncheese »

barshatriplee wrote: Sat Apr 01, 2023 4:52 am You can consider MCP41100 or MCP42100 instead. Those are 100K.
Those fit the resistance range I specified.

I made a mistake specifying 100k ohms. 100K ohms is the remaining resistance needed to resist the remaining power once the device is on the correct setting. The actual resistance needed is probably closer to 1M.

The AD5241BRZ1M has 1M which is plenty of room to work with. It's surface mounted so I'm thinking I solder on some male header pins so it can fit onto a breadboard.

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monkncheese
 
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Re: Muscle therapy dial control

Post by monkncheese »

jps2000 wrote: Sat Apr 01, 2023 5:20 am For good reason such medical devices are battery operated or use a very special medical grade power supply.
What you may do is to use a cheap RC servo to turn the original potmeter. These servos need just a PWM
I want the final device to be low-profile and to be wearable which adds some extra challenge. But I like this solution because it lets me see the rotation of the potmeter -- the amps I'm putting in me -- during testing.

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