Potmeter suggestions for panel mounted pump controller knob

Hi Guys,

For our 17V pumps with speed control, I’d like to create a very simple board that generates the required 5V signal from a 12V input. So the board will just be a voltage regulator, potmeter and connectors.

I’d like a make it possible for this knob to be panel mounted, so I am looking for a potmeter + knob combo that would work well in a brewing panel or stainless table. Similar to a knob on an audio receiver.

Can someone recommend a nice potmeter and knob for this?


  • Linear potentiometer around 10k
  • Panel mount in a round hole


It might be a better idea to specify the potentiometer and allow the end user to choose the knob to match the style of their panel. Most potentiometers have a 1/4" (6.35mm) shaft, and there are many knobs to choose from. It really depends on what is available locally.

You could take a look at DealExtreme for cheap potentiometers and knobs from China.

Here’s a pack of 10 for about $4:

Here’s a small one for less than $2:

There is a silver version.

Here’s a potentiometer and knob mounted on a PCB with pins for easy connection:

But I don’t know the resistance.

Here’s (probably) the same one with a silver knob:

Someone has measured the resistance as 11.5k, so it’s probably 10k with a 10% tolerance.

Those two modules probably don’t come with the mounting nut for the potentiometer and expect you to use the holes in the PCB.

This stuff is really cheap, but you have to buy one to assess the quality yourself. Shipping is free, but delivery can take a few weeks.

Thanks for the suggestions. I think though that it would be nicer to have a bigger knob than something that is 1cm diameter like these.

I want a potmeter that I can mount onto a PCB with voltage regulator and connectors for pump and power supply, so it is really plug and play. I don’t want to do it in a way that you still have to solder wires to it yourself.

I am thinking something like this, but maybe with a bit longer shaft and thread.


I probably won’t buy the potmeters from China, as the taper in a potmeter is fragile for this part I only trust a good brand. You don’t want your pump to stop during a mash, so high quality parts are required.

Good point.

Bigger knobs:

But, Farnell have a huge range to choose from. Again, you could offer your module with or without a knob and the customer could choose to get their own.

simplest circuit to do this is a potentiometer, in series with a single

What kind
of resistance can assemble?

The result
of my calculation is 8 ohm of resistance and 18 WATS to pass from 17 V to 5 v, taking
into account that the maxim consumption of the bomb is 25 WATS.

Are the calculations
correct or am I wrong?


Hi Elco, Do you plan to sell control panel pots and knobs to go with the upcoming 24v pumps?

Wondering if I can order these with the pumps when they are available, or if I should go ahead and make my own in the mean time.

Yes, they will be included for free.

The new pumps arrived. I tested one this weekend and it performed very well. So I’ll add them to the store ASAP.
I’m currently working with a supplier for DIN rail power supplies for the pumps, so I can hopefully add those to the store too so you can buy them in one go.

I have something similar to this for my pumps. If this is what your talking about.



I would like to goto a brewpi for this at some point.

The speed control is built in in our pumps. They have a 0-5V input to set the speed.

The board just generates that voltage from a 12-24V source.