DIGITEN 4 Digital LED Tachometer RPM Speed Meter+Hall Proximity Switch Sensor NPN Red

Item arrived as described, and quickly. Thanks!

Nice little addition to my old Powermatic 45 wood lathe which has a VFD drive plus the 4-step pulley arrangement. I had done RPM calcs based on pulley size and VFD frequency readout and this unit matched them within a few RPM so I'm happy. Will get it installed today. One thing to watch for...in testing the unit I used two 9 volt batteries, one for the display and one for the sensor, and got no reading. Turns out the display unit and the sensor must receive power from the same source. Once I found that tidbit on the web and made the change everything started working fine.

Used this for a one cylinder engine because it is difficult and expensive to find a good tach for a one cylinder. I have tried those inductive mini tachs that use a wire to wrap around the spark plug wire. They are not reliable and not worth installing. This works great. I installed on the end of the crank with a bolt and couple of washers. Grind a slot in the washers for the magnet and use a little epoxy extra security once you know you have the magnet installed with the correct side facing the pickup. I did have to fabricate a bracket to hold the pickup sensor ( not a big deal). It actually reads the rpm changes faster and more accurately than those little mini tachs. I am going to install another one on my other tractor this fall.

The mechanical tach gave out on our boat. So we ordered this to rig up until a new cable could be found for the original tachometer. We had it delivered to a harbor office in a town we planned to visit. It took about an hour of fooling around to decide how to mount the sensor and the readout, but the actual installation was very easy. Here we are a year later, still using this and I have not even looked for a replacement cable for the mechanical tach. This in a marine environment, although the unit is mounted in a place out of the weather. Not bad at all for the price. I'm very pleased.

Spent hours milling a mount for my lathe. Installed everything correctly, paying close attention to magnet polarity, and the display does nothing but read zero. I can see the LED on the sensor blinking as the magnet goes by it so I know the sensor is working properly. Solid 12v power supply. The display electronics appear to be nothing but junk. I will contact seller but not expecting much. However review may change if this is resolved. Otherwise add me to the pile of 1 star reviews (zero stars if I could).

UPDATE: After a lot of trouble shooting I found the problem. One of the 4 wires in the sensor cable (the black one) was broken inside the outer jacket. So it wasn't conducting the signal from the sensor to the board. It's pretty light wire but I'm at a loss how it got damaged *inside* the cable. Luckily the break was only about 6" back so did not have to cut off a lot but that left me with barely enough to reach where I wanted to mount the enclosure. Regardless it appears to be working now. -1 star for no markings on magnet to indicate south pole. -1 star for the bad wire. Seller did reply though and promised to make good if it didn't work. +1 star. 4 stars now.