ON a DA 170.
The DA 170 has two threaded 4-40 holes opposite to the CDI sensor.
I ordered the Spektrum RPM sensor and used a PVC pipe, that was then machined to size and fit the two together.

i have then binded the receiver, the telemetry module, and the Iphone interface, and when i rotate the crankshaft, it reads RPM based on speed that i twist it.

I did something very similar with my DA-170 and also my DA-85. But I don't get consistent readings. Sometimes I look at the rpm while flying and it is reasonable (like 5000 rpm). then it jumps to 10,000 rpm then to 7,000 rpm. I don't trust it at all.

This happens on both of my setups, so I don't think I have two defective sensors.

Please advise how your works in the air.

i sure will,
have you tried to set the sensor farther apart from the collet, by using some washers? just wondering if it is too close, then it picks up on other signals and it becomes less accurate. i do not know myself since i am just setting it up now.

I mounted mine as in these pictures. I tried moving it very close and also with some space between the sensor and the hub. I think I also tried mounting it like you did. This was over a year ago and the details are getting fuzzy.

you are using a metal bracket, and i wonder if this caused interference. i used PVC material, but i think we need to use something like plastic. same thing with the CDI sensor, it is a plastic.

or you could just "y" connect into the sensor used by the ignition... Did that on my DA 50.. worked great.. no extra parts

I tried the "Y" connector and got nothing. I'll have to revisit that approach.

Make sure you tap into the correct wires... My plane is at a friends house or I would take photos for you

hi, let me know what you think, this is the sensor from the saito, it is not a hall sensor, but i was told it should work. now the sensor only has two leads, a black and a white. i suspect the black is negative and the white is the signal.
the attachment for the telemetry has black, grey, and red. the black from sensor is attached to black from telemetry, the white from sensor is connected to the red.

will this work??

my daughter was the one who wanted me to put this smilee face one there

did not work. no signal pickupo from telemetry module.

ok, just did this, and now it is reading RPM, amazing. will be cool if it is accurate. will test it in 3 or 4 days from now and post results.

this is what i did, a quick fix. i got a 3 inch servo extension, then i switched the position on one side only of the red line and yellow line. now it works!!!

hope this may help others in future.

Actually, ortho, on the two wire unit the magnet is only closing a very small microswitch. There is no signal, there is no negative. It is only a continuity device completing a single line circuit.

Nice face lol

I suggest re-pinning the connector on the switch and eliminating the extension. Just remember where the wires need to go

This is what I did with mine on a DA120, it's so easy a caveman can do it, just cut the sheet metal with scissor and drill holes to fit into the engine.

Reading is very accurate since the whole sensor is right above the magnet. FYI.

thanks robbin and jack. Question for you jack, how has it worked for you with regards to accuracy of rpm reading. during flight, does the reading jump around?

does the length affect the signal?
i am afraid to take the pin out, i may mess things up

there is a delay in the reading from STi module otherwise the reading is accurate, no jumping around. I use it to fine tune my engine RPM.

maybe the vibration make the gap between magnet and sesnor inconsistent?

Originally Posted by orthobird

thanks robbin and jack. Question for you jack, how has it worked for you with regards to accuracy of rpm reading. during flight, does the reading jump around?

does the length affect the signal?
i am afraid to take the pin out, i may mess things up