Measurement Devices: Tachometers

[MachX]

Hello All,

I am experimenting with DC motors and different speed settings, and I am looking for a way to measure RPM at different voltages and loads. I have been looking at different tachometers and trying to determine what my best option is. The reading does not have to be super sensitive, and I am trying to make it as simple as possible. So far I have found an analog and a laser hand-held tachometer which seems to be my cheapest option.

http://www.aliexpress.com/wholesale/wholesale-rc-tachometer.html

Anyone used these or have any suggestions for other tachometer solutions that are cheap and for small scale 0.25" or so shafts?

I know a device exists that will read rpm from a given motor based on voltage input, but unfortunately said device would be specific to its motor. I don't know if I want to try and build such a thing for the motor I have.

 

[anorlunda]

A magnetic pickup will create a pulse train whose frequency is proportional to RPM. Ditto for an optical pickup. That laser device you mention is probably an optical pickup.

 

[Ranger Mike]

i have used the rubber wheel type hand held tachometer but really like the strobe light type. More expensive but much easier to get a good reading