RPM via RF 1

[aack]

I am currently kicking around a way to reliably transmit engine RPM over an inexpensive low power RF link.

The purpose here is to get rid of the physical cable connection between the sensor and gauge. In this application the cable is the weak link. If the cost per retro-fit (non-list) stayed under appx 300-400 bucks, it would be quite cost effective. Lots of metal in the area and quite a bit of noise. The RPM is non-critical but needs to be realitively stable. I could do a bit of signal filtering at the A/D box. Distance = 150 - 200ft. Sensor Frequency output = 50Hz to appx 4kHz. High Vibration.

Idealy I was planning to use a relativly high voltage (10-60 VAC) mag sensor to drive a n off the shelf transmitter (like those from Abacom and Linx). I don't think there are any 'Current' supply issues after the monitored gear gets moving, although I suspect that I need to also add a charge cap or battery, so I don't miss start up RPM.

If I could keep all of this small enough, I'd give up the start up RPM in deference to size. It would be nice to 'screw' the "radio" dierctly on the back of the sensor.

Wouldn't bother me to fully pot the finished device and plan to replace rather than repair when a failure occurs.

Anyway, just tossing it around at the moment and thought I'd throw it out there.

Willing to listen to any and all ideas, especially given I am not well versed on transmitting analog sensor signals via a local link.

Thanks,

aack

 

[frocha]

Howdy aack, the frequency range of the RPM signal is well with in teh range of voice communication. Maybe you can convert a wireless microphone into a remote sensor, and interface the receiver side to your instrumentation (display).

Hope this helps.

 

[cellpoint]

Hello aack,
It has been a long time since your post, but I just saw it and I have radios that are made to transmit such data and are very small and relatively cheap, with very low power requirements. (actually they are designed to be throw away after 2-3 years).
Let me know if you still have any interest.

 

[MrSpock]

I take it you are providing your RPM output as a frequency across the range of 50hz to 4khz. If this is true, would think you could do this with a microcontroller and trf6900 transceiver or wit 2410 transceiver. The parts are not to awfully expensive well under
your 300 -400 dollar range. I could design it or I will be ahppy to answer another question.