Posts by Rudolf

    We solved the issue. New small device connected to RPM device, one cell battery is connected into that device, instead of SparkSwitch Pro, SparkSwitch Pro battery input is supplied with receiver voltage (Y male/male+male), means data port voltage is shared with battery port V+ pin.

    When SparkSwitch Pro is powered ON, then RPM device is powered, additional circuit will connect battery with ignition module.

    No warnings, not over-current risk (mainly for Zenoah ZG20 and ZG26 and Saito 60 R3), all is working smoothly.

    Hallo all,

    it is solvable, I'm adding voltage regulator to RPM device for ignition modules with one cell power supply. Means, you will plug two cell battery to SparkSwitch Pro, but ignition module will be supplied over voltage regulator with 3.75V (configurable with jumpers)

    This updated version will be available on Thursday next week.


    Combustion gas engines ignition modules without additional pulse signal with RPM output are unable pass directly RPM information into SparkSwitch Pro (SPW) device. It was the reason, why developed special accessory device for SPW.

    First version of accessory was simple circuit, able to read mainly hall sensor signals, and after amplifying of the signal, passing this signal into SPW device. But this accessory was unable read some special signals, mainly from magnetic coil, used in DA ignition modules. Same case for Valach ignition modules, where was also problem with dual controlling of ignition module. Valach ignition modules required connection to receiver for switching on, therefore two control signals needed, for switching on/off of ignition module.

    Current version of RPM accessory is designed for usage with all types of ignition modules. It is microprocessor-controlled device, which is able read any input signal from any type of engine sensor. Side effect of the design is fact, that all cables from ignition module are connected to this special accessory, and only one lead is connected to SPW device. It is big advantage also for Valach ignition modules, because module is connected only to accessory device, and is not needed connect ignition module to receiver, functionality of ignition module is controlled only by switching SPW on/off. Accessory device controls the ignition module and read signals from the sensor.

    RPM accessory is small device of dimensions 14x32mm, with five JR male connectors in one row, on the left side. All cables from ignition module are connected directly into that device.

    RPM accessory device is configurable for different types of ignition modules, but main process of analysis of input signal from engine sensor is done by special firmware, analyzing the signal with fast analog to digital converter. For controlling of all functionalities of accessory was used micro-controller SAMD21 Cortex M0. Accessory device is designed for two independent circuits, separated by optocoupler, to eliminate possible interference's from ignition modules. Accessory power supply circuit is especially designed for elimination of possible noises. Signal from engine sensor is separated using instrumental operational amplifier, to be sure not disturbing ignition module input circuits for right operation of spark timing and distribution.

    Generally, we have three types of ignition modules:

    1. Basic type, engine sensor of Hall type, connected to ignition module, and ignition module powered by second cable, battery connected directly to ignition module (using switch).

    2. Ignition module controlled by receiver, means switching on the module using receiver channel. Battery connected directly to ignition module (using switch).

    3. Ignition module with magnetic coil engine sensor. Signal generated by magnetic coil is hard to read and pass into SPW, therefore functionalities of RPM accessory are needed for analyzing the signal. Battery connected directly to ignition module (using switch).

    Ad 1)

    Connection setup: (OS Max, Zenoah, ZDZ, EME, DA 35)

    P1 – connected to engine sensor using patch lead male/male (*)

    P2 – connected to ignition module sensor cable directly, or using patch lead male/female

    P3 – empty, not connected

    P4 – connected to ignition module power supply cable, using patch lead male/male

    P5 – connected to SPW using patch lead male/male

    Jumpers: inserted J2 and J3 (**)

    Ad 2)

    Connection setup: (Valach all ignition modules for all engines)

    P1 – connected to ignition module power supply cable, using patch lead male/male

    P2 and P3 – connected together, using short patch lead male/male

    P3 – connected to ignition module output (usually connected to receiver in setup without RPM accessory device)

    P5 – connected to SPW using patch lead male/male

    Jumpers: J1 and J3 (**)

    Ad 3)

    Connection setup: (Desert Aircraft all ignition modules excepting DA 35, see 1)

    P1 – connected to engine sensor using patch lead male/male, wires 1 (signal) and 3 (ground), please use patch lead without wire 2 (+V) (***)

    P2 – connected to ignition module sensor cable directly, using patch lead male/female, wires 1 (signal) and 3 (ground), please use patch lead without wire 2 (+V) (***)

    P3 and P4 – connected to power supply output from ignition module, using Y-harm patch lead male/male+male, please use patch lead with only power supply wires 2 (+V) and 3 (ground) (***)

    P5 – connected to SPW using patch lead male/male

    Jumpers: none, empty jumper block (**)

    (*) – patch leads with JR connectors for all ignition modules excepting OS Max. Futaba connector has guide, which is not possible plug into JR connectors used in most of ignition modules.

    (**) – 5 position jumper area, please do not connect jumpers into first two positions! Those pins are used for programming of device


    In all cases is ignition module controlled by SPW, not needed additional switch, additional channel. It is better to use accessory device as junction box for all ignition module leads, and single lead connected to SPW. Better organization of cables, better resistance to noise, interferences.

    Accessory device firmware is providing small hysteresis for rpm pulses, means the visualization is more stable, not ‘jumping’ rpm values. Hysteresis is small, not affecting fast rpm changes, but helping out to have stable information about rpm.

    For further details, orders please contact me directly.


    yes, directly for Valach ignitors we developed new version of SparkSwitch Pro accessory. For 210 Valach the ignitor is connected to receiver. In our solution is connected to our device, device is connected with SparkSwitch Pro and only SparkSwitch Pro is connected to receiver.

    On the picture you can see Valach single cylinder version of ignitor. This ignitor is the same as your for multicylinder engines, with one lead for battery, and one lead for receicer. Both leads are connected to our device, and device is connected to SparkSwitch Pro. This device controls igniter, instead of receiver. Means, you will switch on igniter switching on the SparkSwitch Pro.

    Have a nice day


    Hallo Reiner,

    do not worry :-) Solution exists! Send my your address as private message and I will send you device, which convert weak magnetic coil signal to clear pulse. It is working properly and new version of this device is microprocessor controlled, analyses input signal and passing clear pulse into SparkSwitch Pro.

    all is solvable :-)




    unfortunately in some ignitors with magnetic coil sensor we faced lot of problems with reading the signal. It is a reason why we using additional device for signal level aligning. I measured in three DA ignitors, the same type, three different values. Vendor is using special amplifiers inside ignitor to align input coil signal to usable level.

    In case, when we connecting signal from sensor to mentioned additional device, device is analysing the signal and based on analysis (it's provide by microprocessor and appropriate software) is passing the signal into SparkSwitchPro. In that case we are sure, that the signal is clear and not noise, no spikes.......

    Device weight is less than 7grams, and dimensions 13x25mm, I'm pretty sure that it is not problem :-) Anyway, device is helping out to have order in cabling, because all cables from ignitor and engine are connected into the device and single output is connected to SparkSwitchPro.

    have a great day


    magnum : old 3w ignition modules uses magnetic coil sensor, generating electrical 'spike', the same as in DA ignitions. New 3w using Hall sensor. If you simply connect sensor from old ignitor using Y to SparkSwitch, nobody can guarantee, that in full range of throttle you will able measure correct values. For all ignition modules with 'weak' sensor values we are using some additional hardware to 'clean-up' signal passed to SparkSwitch.

    UPDATE !!!

    I developed new version, because in some cases mainly with DA twin ignitors we had small issues with the sensor signal. Therefore to be 100% sure, that all, really all ignitors will be working properly with the SparkSwitch Pro, new version is microprocessor controlled, read absolutely ALL signals from ALL sensors!!! It's so important, to be 100% sure, that after connection SparkSwitch Pro with accessory device all is working immediately correctly.

    We tested this device with twin DA, single DA ignitors, and it's working absolutely properly, smoothly, without any doubts!

    Hi Roly,

    I'm so sorry that you have problems, but right now we tested 14SG with 7008SB receiver and SparkSwitch Pro. Please set your system to FASSTest 12ch, and it will be working properly. Please let me know if you was successful, if not, tomorrow we will send you detailed step by step with photos :-)

    But if you choose right mode, then it really work w/o issues.

    have a nice evening


    Some details about right installation/connection:

    1. On image you can see, how to connect all cables, if there is something unclear, not exact, please tell me!

    2. On second image you can see, that engine turned little bit, to change position of hall sensor, immediately is LED on device ON.

    It is really helpful, to have immediately information, that signal was passed to SparkSwitch Pro. In case when LED stay off, not blinking, when you rotate engine, then something went wrong, and signal is not passed. But I hope that never happen :-)

    3. Pinout

    If somebody will need help, please do not hesitate contact me immediately, also share please your experiences with new device!

    For all users of multi-cylinder engines, please have look into my post in thread SparkSwitch PRO and multi cylinder engines

    Couple of pilots are using this new device developed especially for SparkSwitch Pro, me too (first one, prototype :-)) and all are really satisfied with possibility to measure MIN/MAX temperatures on cylinders, using SparkSwitch Pro directly. I'm using this device also for one cylinder engine, with 2 sensors in different positions inside cowl. It's helpful for me, to be sure that engine is well cooled.

    Hallo All,

    new version is ready, on pictures you can see differences in size (new version is smaller), and new version has LED indicator of functionality, showing (blinking) status - sending pulses into SparkSwitch Pro:

    1. Here you can see both, installed old version, but connected new version, SparkSwitch Pro is ON (LED on fuselage)

    2. Engine is sending RPM info to SparkSwitch Pro (on device LED is ON)

    3. Little bit more rpm to be able see it on transceiver telemetry:

    All, whom I sent old version, I will send gratis new also, not need pay anything :-)

    Have a fun



    I would like inform all pilots, interesting into measuring of temperature for multi-cylinder engines, using SparkSwitch Pro, now is available device, whose is available to send into SparkSwitch Pro Minimum/Maximum/Average temperature of 2/3/4/5 cylinders. Means, this device is connected using patch lead to SparkSwitch Pro Temperature sensor port, and all sensors (available together with the device, cable length 40cm) for each one cylinder are connected into device. Device is controlled by one PWM channel, 3 position switch 0-Avg, 100-Max, -100-Min temperature.

    Dimensions: 46x22mm

    Wight: 10g without sensors

    Inputs: 1xPWM, 2 up to 5 temperature sensors

    Output: 1x output to SparkSwitch Pro temperature sensor port, using two wire patch lead

    Voltage source: Rx/PWM Channel, from 3.3V up to 8.4V

    Prototype was tested with MOKI 400cc 5 cylinder engine in the flight.

    In case, if you are interesting into it, let me know, device will be available from March 2, 2019 :-)

    have a nice evening


    Hello Kjell,

    I saw right now your post, I'm interesting about all related to SparkSwitch Pro. I know, that it is little bit late :-) maybe you resolved your problem using nice device from CB Elektronics, but for one my colleague I developed small device for MOKI 400cc radial 5 cylinder engine. This device is sending maximal temperature from all 5 sensors, and you can switch using one channel to send average temperature. Device has 7 connectors, one input (plugged into SparkSwitch Pro into temperature port), 5 connectors for each one cylinder, connected 5 temperature sensors, and one for PWM signal to switching maximal/average temperature (without using this port the default value is max). Colleague is satisfied, getting right information about the temperature and told me, that he is using mainly maximal temperature information, its important for him, and getting only one temperature info on transmitter screen makes it more readable.

    have a nice day