SparkSwitch Pro - Futaba - DA35 - No RPM

  • Greetings,

    I have everything working but the RPM sensor....which is the primary reason I want to use it. FYI...I updated it to Firmware 4.0 which is the latest and I had to reverse the polarity for the bulb to work.


    At first, I couldn't get the engine to run with the SparkSwitch Pro as the input. I knew I had voltage going to the ignition, but it wouldn't run. I noticed the only difference with the TechAero and the SparkSwitch Pro was that I had a signal wire also connected to the ignition box. I removed the signal wire and it fired right up.


    As you can see in the attachment, everything else is working fine. The temp is on the next page but it is also working. I'm drawing 0.1 amps, the battery is at 7.8v and I've used 24mah up to that point.


    I've also attached a picture of the wire wrapped around the ignition wire.


    Based on everything I've read, it appears that there is an issue with either the pickup or the SparkSwitch Pro as far as using it with a DA engine goes.


    My questions are:

    1. Any suggestions on what I can do different?

    2. Is Powerbox looking into this issue since there are several threads that indicate others are having the same problem with the DA70 and DA120.


    Thank you!!



  • Hello,

    what I see here is your Pickup is one of the first units: the cable is very short. Can you solder any cable - 30cm - additional to the sensor wire of the Pickup? Doesn´t matter what cabel - even 1 strand of a servowire will work.

    With more wire round the ignition cable it will work.

  • I have the supplied Y cable connected to the Ignition socket on the SparkSwitch. I have an extension connected to the Y cable that goes to the input of the ignition. As I said in my first post, I had to remove the signal wire from the ignition because the engine would not run with the signal wire connected to the ignition. In other words, I am simply applying power from the Sparkswitch Pro to the ignition. I have read the voltage and it is 5.9v as set in the Power Terminal program.

    I have the RPM sensor connected to that same Y cable as the ignition. So the ignition and the RPM sensor are connected to the Y cable that is connected to the Ignition socket on the SparkSwitch Pro.

    Thanks for taking the time to talk this through.

  • A little more information on removing the signal wire from the ignition.

    When I couldn't get the engine to run, I put the TechAero back on and the engine fired right up. Thinking the voltage wasn't getting to the ignition, I checked it with a meter and determined it was getting 5.9V from the SparkSwitch. I then thought it could be the Y cable so I plugged the ignition straight into the SparkSwitch (RPM Sensor not connected) and the engine ran.

    I then replaced the Y cable with a new cable and the engine wouldn't run with the RPM Sensor connected. I then disconnected the RPM Sensor from the Y cable and the engine ran fine. At that point I knew it was something to do with the RPM Sensor being connected to the Y cable. Figuring the RPM Sensor's signal cable was carrying something from the sensor to the SparkSwitch, I decided to remove the signal wire from the RPM Sensor lead. The engine ran fine with that lead removed.

    However, since I'm confident that signal from the RPM Sensor needs to go so the SparkSwitch, I then put it back in and removed the signal wire from the ignition input. Now I am just putting power to the ignition from that wire, but there isn't any signal wire connected to the ignition. I'm not sure why the signal would prevent the ignition system from working, but it does.

    Based upon that, I am confident there is a signal on the signal wire coming from the RPM Sensor (that is what was preventing the ignition from working). To me the question is why isn't that signal being properly used by the SparkSwitch to display the RPM.

  • Hello,

    I'm using RPM Pickup with DA-70 boxer. The 'antenna' wire is in origin length. The wire is on spark plug cover. I used shielding of the device and fit the device directly on the spark plug wire. I'm absolutely satisfied with the results.

    In the case of other ignition systems, OS/3W is this solution not needed, DA has really very good shielding on the spark plug wires! It is very good against interference.



  • Hello,

    everything sounds correct. The question is: what signal wire is that from the ignition, I heard that the new DA ignitions have a Tacho output, but not sure when this will come. So the question is: can this be used directly to the SparkSwitch fro RPM?

  • I'm in direct contact with DA guys, and here is the latest information about the possibility of RPM measure using the existing DA solution. So far, no other solution, only to use RPM Picker or special RPM device.

    Information from Vernie (DA):

    If you are wanting to get RPM readings you can actually add a hall sensor onto the 100L. Its not very easy to do with the sensor that comes on it which is why we predrill all the engines so that you can add an additional hall sensor on there for RPM readings.

    Vernie Aikins

    Desert Aircraft

    1815 S. Research Loop

    Tucson, AZ 85710

    Ph 520.722.0607

    Fax 520.722.5622

  • Richard,

    There is no reason to need the signal wire to be connected to the ignition for this system to work, correct?

    If that's the case, due you think I have a defective RPM Sensor. Everything else on the SparkSwitch is working perfectly.

  • Rudolf,

    Another question. Is yours connected to a Futaba? I am wondering if it is possible that the signal from the RPM Sensor is not being processed correctly by the SparkSwitch to allow it to be displayed.

    Thanks again!

  • Papatrey But as I can see, you do not need any pickup sensor for the DA 35. There is hall sensor, and if you will connect the white wire from the sensor to SparkSwitch Pro signal wire - output to ignition system power suppply, then you will get nice signal for RPM.

    Let me know if understood.



    edit: output from Sparkswitch to power supply connector on ignition - only +- wires, not signal wire. Hall sensor connector on ignition - use Y harm and connect normally the sensor to ignition, and from 2nd output of Y use only signal wire to SparkSwitch

    edit2: in the past I used SparkSwitch Pro with Futaba 18sz without any issue

  • I'll look into that (I don't have the newer ignition so I'm not sure which white wire you are referring to), but more specifically, did you use the SparkSwitch Pro, a DA engine, and the Futaba 18sz?