Spark Switch Pro and OS GF-30 RPM

  • Hello Richard,

    just ordering the Spark Switch Pro for my OS GT 33 .

    It looks we're going to have a solution soon for the OS Ignitions and the RPM issue?!

    Any ideas what that would cost Rudolf?

    Regards Jürgen

  • hallo, good evening. Yes, indeed, 'issue' with OS IG resolved. All tests on the ground done, Now I'm waiting for some acceptable weather, without snowing, to be able 'maiden fly' with the new accessory.

    Regarding price, if you're interesting for that, I will send you accessory by post, I would like only post fees back.

  • Hi Jurgen, it's working in the fly properly and it's really stable, great to have rpm telemetry for OS engines :-) I tested new device accessory in Edge V3 78" with OS MAX GT33 engine. I reworked device, because initial version had two and two connectors on opposite sides, means it was unable to use shrink tube for some isolation, I thought that I will build some small metal box but it's really not good idea. Therefore I reworked PCB and now new version is 25x17mm and all 4th connectors are in one line, therefore not needed any box, used easy and perfect isolation with transparent shrink tube. Device is working in whole range of power supply, from 4.8V to 8.4V, not depend on voltage setup, max 2cells of LiPo or LIOn of course.

    Summary: It's ready and properly working with PB SparkSwitch Pro for full voltage range (5.9V using internal regulator or over 8.4V). Weight 5g, dimensions 17x25 mm, covered by transparent heat shrink tube. On picture is version without shrink tube. On prototype I used black shrink tube, now waiting for delivery of transparent :-)

    Connectors from left to right: 1-Spark Switch, 2-Input to Ignitor (Power Supply), 3-Output from Ignitor, 4-Hall sensor on engine. Spark Switch can be configured for 5.9V or full 3 cell voltage.

    Another one will be installed in Extra 330LX 92" with OS MAX 60GT.

  • Hello,

    I don´t think that it works with DA ignitions. DA doesn´t use a Hall sensor with a solid digital signal. It works different. It´s only a coil in the RPM sensor which gets only weak induktive pulses from the magnet. The analog signal is then amplified in the ignition.

    DA will come with a tacho output in future.

    We are working on a solution for that - it´s already layouted, but had no time to test it.

  • Hi, signal from sensor (any) is modified to clear pulse and passed into SparkSwitch. Of course I not tested DA, but as can I see in documentation, it should be work.

    Let me test it, one colleague is using DA-50 engine, we will test it at Thursday. Will let you know.

  • Hi Richard,

    today I'm working from home :-) therefore I had time for small experiment, I was really curious about passing some weak, analog pulse, with amplitude from 0.8V to 6V.

    Threshold is min 0.8V without any changes, in case when we will need lower voltage, I can update resistor in amplifier. But I got nice output pulses at device output.

    DA ignitors are working from 4.8V to 6V, but I'm not sure about the sensor signal, as I mentioned, I will let you know at Thursday, but from my point of view, it should be work. If you have some another doubts, please tell me, to be prepared for another possible issues at Thursday, because I never used DA.




  • hallo Richard,

    thanks for warning, but, to be honest, I expected that and initially I designed something like instrumentation amplifier between input signal and optocoupler, therefore I can say, that I will not harm signal passing to ignitor's amplifier.

    But, we will see. All is solvable :-)


  • Salut All,

    because I'm not very patient guy, right now we did the test with colleague on balcony :-D

    Extra 330SC, DA-50.

    Initialy testing old setup with normal killswitch. Measuring full range from idle to 7380rpm using optical rpm meter.

    Replaced old killswitch with SparkSwitch Pro, wiring all properly (without temperature sensor), programming telemetry on 18SZ, on third flip started, full range of rpm's as in the past without any issue!

    It's working as I expected.

    Without any change on device :-) No impacts to ignition timing, absolutely separated signals.

    Have a great day, I'm satisfied!


  • yes, indeed, not only US as I can see :-)

    Colleague after yesterday's tests ordered 2 SparkSwitch Pro and he will use it with DA engines. He is using lot of years only DA (I'm using always OS MAX, GT33 or GT60, and now is new GT120), because is absolutely satisfied with DA.