Hi Cody, just to keep it simple and useful for yourself, yes you can try with another Potentiometer until the scale pleases you.
I like your idea with the females on the circuit board.
For your reference, at 12 V you need only 250 milliamps to open the TB completely, whereas the PWM controller has a range from low to 2 amps. So, with the higher value from the new Pot, you went from 1/8 turn to 1/4 turn, maybe you can test with the biggest value you have and work from there ?
I tried a various range of Potentiometers all the way up to 1M, the throw did not change unfortunately. Anything more than a 100k pot you start to hear a squealing feedback noise coming from the motor. The smoothest operation comes from a 250k pot. I don’t know exactly how these PWMs utilize the potentiometer but it doesn’t seem to matter much on the actual resistance.
Edit: I actually have been spending some time tearing apart a different RME87 that was corroded and wouldn’t actuate anymore. I tested the motor after removing the gears and the motor spins 360° continuously. Wouldn’t that classify it as a Stepper motor and not a Servo since the position sensors are external?
Where are you putting the pot in the circuit? The pwm circuit with the rioande controller is a 555 chip. TBH it might be a lot easier to use a microcontroller and l297 or whatever to control it. Then it is a lot less electronics.
I would probably use a pi pico flashed to use arduinoIDE or something similar. They are 32-bit vs the 8-bit arduino.
But you can use this, you just substitute a motor driver like the l297 instead of the lightbulb. The l297 is an h-bridge, and adafruit has a decent tutorials for h-bridge and motor control, to get forwards and reverse and a few other things going for you.
For a power supply, you can get an adapter for an ATX power supply, for like 5 bucks from amazon. which gives you 12v, 5v, and 3v. I got a couple of small cheap variable ones power supplies. I would post the link but the potentiometer to control them isn’t very precise but it does have digitial read out. I don’t recommend them but they were only like 5-10 bucks.
No it is not a stepper not a servo, its basically just a dc motor which is fed with and moves based on DC voltage at a limited amps. ( Thru an PWM controller )
a 12 VDC and max output .250 Amp pwm controller would do the trick for you.
The one you pointed out , from amazon, has a bigger than .250 amps continuous output, as per description on amazon
To add to the clarification, a servo motor is actually an assembly of four things: a normal DC motor, a gear reduction unit, a position-sensing device (usually a potentiometer, an optical or a magnetic sensor.), and a control circuit.
If there there is a circuit board on it, then the logic is on that board to control the position which with the position sensor input would in effect make it a servo, and that changes a bit how to control it.
The way I’m thinking of using the throttle body it doesn’t have to move terribly fast. I was just piddling with the idea of using it as my air adjustment. My main concern was leaving it in wide open mode if it would overheat the motor.
The Arduino H Bridge idea seems to be the most refined method, at least then if something doesn’t work right it’s my fault and not the poor guy making these PWMs.
That is how i am using my TBs. Two control wood gas, the other two control my air supply.
As long as your not over driving the motor…i.e. bottoming it out with excessive current, the motor should be fine…after all, that is what it was designed to do.
Thats how I’m controlling mine. And they work great.
Your main goal is knowing exactly what percentage the valve is open by the position of your pot (in my case i used a rotory encoder in place of the pot, so i have a digital readout.)
Beacuse after the valve is installed your not going to be able to visually see what position its in.
There is something to be said for good old manual control…but… i like not having to worry about routing hard control lines threw the firewall and not having too tight a bends in them.
Plus, you get this electricly controled valve working, incorporating matts auto mixer code into your arduino script will be fairly simple.
It is the easiest electrically. and you can change the code, without messing with the wiring. The ArduinoIDE will work with several microcontrollers, my only suggestion is not to use the 8-bit arduino. It will probably work, but there are a bunch cheaper, faster and better on the market, and it future proofs you if you decide to add things to to it.
Man just get a 1/5 scale Hobby servo, Those can litterally shear that valve axle off. They are increbibly strong and dont cost much. Then you use the Arduino Servo example code to run it. Dont under estimate these hobby servos, they are not toys and are used in industry all the time.
Dont worry about this freezing up, its not your throttle. Never use electronics for your throtle plate with wood gas. Its not going to run away, if anything you mixure will just get off and you will have a weak mixture.
Matt for my Square Body I am using those servos, albeit a more generic one. The Automixer for that is pretty much by the book. Only adaptation I’m using is the direct drive coupler, so the axle of the servo will be inline to the shaft of the mixer valve.
And when I was talking about the Woodgas lines I meant the cutoff valve for the Woodgas feed. I think a spa gate valve and linear actuator would be pretty ideal. Bobmac uses one without the rubber gaskets to prevent it hanging up and reports it shuts off woodgas feed when running purely on Dino.
You do bring up a good point on the hobby servos. Publicly available code and a lot less stuff involved with using them, and you could use whatever valve you find.
