I’m repurposing a treadmill motor for a different project. Is there any way to convert the “mph” sensor ,pardon my ignorance, to a digital rpm read out. Please see picture

 

No Pic!?
The sensor is usually on the belt, unless you have one of the few which the slotted wheel on the motor.
You would need to build a LCD readout using a small picmicro.
Max.

 

On the TM's (tread mills) I've scrapped, the magnet is on the pulley for the tread belt. The best way I can think of reading out RPM's is to put a reflective strip on the flywheel of the motor, close to the center where it won't be subjected to much centrifugal force and use an optical reader to measure the number of times that reflector passes the sensor.

I have an old TM motor running my bandsaw. It has more power than the original motor AND it has the added benefit of being a variable speed bandsaw. A proper replacement motor for my bandsaw would have cost $185.00 (US), and I had the motor and motor controller laying around. A little welding and I had a bracket for the TM motor. There's also an added benefit if having to put a push button to bring the motor to absolute zero before it will begin moving; meaning it's less likely to start by accident.

 

There were a few using a Johnson motor that had a large slotted wheel on the back and used a photo sensor.
Max.

 

No Pic!?
The sensor is usually on the belt, unless you have one of the few which the slotted wheel on the motor.
You would need to build a LCD readout using a small picmicro.
Max.

Sorry every time I try to attach a photo I get booted. There’s a slotted wheel behind the drive pulley with a red black and white wire. I’m assuming this is to give the mph readout. I would like to get a digital rpm read out and before I remove that part from the motor was just wondering if it were possible in its current condition

 

 

You could make use of it, there should be a manuf. No on the opto sensor, you then need something to interface to it and convert to the readout you need.
Either off the shelf, or a DIY unit.
Max.

 

On the TM's (tread mills) I've scrapped, the magnet is on the pulley for the tread belt. The best way I can think of reading out RPM's is to put a reflective strip on the flywheel of the motor, close to the center where it won't be subjected to much centrifugal force and use an optical reader to measure the number of times that reflector passes the sensor.

I have an old TM motor running my bandsaw. It has more power than the original motor AND it has the added benefit of being a variable speed bandsaw. A proper replacement motor for my bandsaw would have cost $185.00 (US), and I had the motor and motor controller laying around. A little welding and I had a bracket for the TM motor. There's also an added benefit if having to put a push button to bring the motor to absolute zero before it will begin moving; meaning it's less likely to start by accident.

I’m gonna do the same thing to my lathe and bandsaw. What set up did u use for on/off, control etc?

 

I’m gonna do the same thing to my lathe and bandsaw. What set up did u use for on/off, control etc?

What is the type/model of the motor board you are using?
Max.

 

What set up did u use for on/off, control

I used the motor control board to control the speed. The bandsaw switch was used to either turn power ON or OFF to the control. Since a normal treadmill will not just start at some random speed, the motor control must first set the speed to zero. On the one I used there are three terminals; one for positive, one for negative and one for either PWM or a variable resistor. I think I used a 10KΩ pot with pos and neg tied to each end of the pot and the wiper was tied back to the third pin. I then added a push button and connected it to (I believe) neg and the wiper. Momentarily pressing that reset the motor speed to zero, then when the button was let go the motor would begin to spin at the speed pre-selected by the pot.

When cutting thick wood I opt for a lower speed than when cutting thin veneer. Plastic also gets a lower speed. This prevents excess heat and burning of the cut.

I'm going from memory because it has been 3 or 4 years since I did that. Possibly longer.

 

Since a normal treadmill will not just start at some random speed, the motor control must first set the speed to zero.

Not always true, for the MC-60/80 SCR bridge model there is a resistor to snip for same speed start mod, on the later MC2100, no mods necessary, it ramps up to previous RPM automatically.
Max.