Digital Photo Tachometer

TractorGuy · Jun 27, 2019

I always wanted a method to measure RPMs on stuff that don't normally have a tach connected to them. I considered one of the old contact type analog units but never bought one. The other day I decided to act on this want so I looked them up at HF and saw they had them for $38. Being the cheapo I am at times I decided to look on ebay. As I normally do I put the item name in the search field then set the search parameters to US Only and sort by lowest price. Found one in California for $9.74 shipped so I bought it. Just arrived today and I tested it on the PTO shaft of my tractor and on the flywheel of a lawn tractor. Seems to be VERY accurate.

With the tractor tach reading just over the PTO set point I read 547.4 RPMs at the shaft.

On the lawn tractor it read 3266 RPMs.

WranglerX · Jun 27, 2019

Does it require you to have at least one white spot on rest of dark background?

There is also some smart phone apps the will do same thing.....BUT not all apps will work with all phones... It's sort of pot luck....

Dale

TractorGuy · Jun 28, 2019

DL Meisen said:
Does it require you to have at least one white spot on rest of dark background?

There is also some smart phone apps the will do same thing.....BUT not all apps will work with all phones... It's sort of pot luck....

Dale

It comes with a strip of white reflective tape. All I did was cut a small piece off and stick it on. I don't think it matters much about the background but it obviously could not be solid white and work.

ptsg · Jun 28, 2019

I also have one tachometer like this and it just eats batteries like butter, even when it's just stored. I would suggest to remove the batteries after using it. Or maybe I just got a defective one.

TractorGuy · Jun 30, 2019

ptsg said:
I also have one tachometer like this and it just eats batteries like butter, even when it's just stored. I would suggest to remove the batteries after using it. Or maybe I just got a defective one.

I store all my infrequently used battery operated stuff with the batteries removed. I keep the batteries in a plastic bag and just install it when I need the tool. Otherwise you will most likely find a corroded ruined mess when you need it. I have several tools that use a 9 volt battery so I just use the same battery for all of them.