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Construction / operating manual QuadroPPM12

=> Deutsche Version dieser Anleitung



Quadroppm12 empf.jpg

Many Multicopter-Controller boards (such as the QuadroControl) use a so called "Multi Signal" for connection with the model receiver. This is a signal which contains the information of every channel, so you won't have to connect every channel with a seperate cable to the controller board.

Unfortunately only a few PPM-model receivers support this multi signal. The QuadroPPM12 generates a multi signal out of up to 12(!) single servo signals of a standard model receiver (including 2,4GHz and PCM receivers) without modifying it.


  • Transforms up to 12 servo signals into a multi signal
  • Number of channels is configurable by solder jumpers
  • The frame rate depends on the number of channels (less channels = higher frame rate (min. 20ms), more channels = lower frame rate (max. 28ms))
  • Output signals stabilized by crystal
  • Can be used with most standard model receivers => tested receivers
  • Detection of the fail safe feature of some premium receivers ensures the functioning of the emergency landing feature of the copter at signal loss even though valid servo signals are available. Configurable by solder jumper.
  • Status LED.
  • Compact dimensions of the PCB: ca. 21,5 x 22,5mm
  • With Bootloader. Can be updated via serial Port or USB (with appropriate adapters).

Safety instructions

I do not guarantee the correct behavior of the PCB or the included Firmware! You use the PCB and the Firmware at your own risk! You alone take the full responsibility for a complete test of the total system. Every Aircraft -including multicopters- is potentially dangerous! Inproper use or failure might lead to crash, worst case might result in death! A multicopter and this PCB are not suitable for kids, they must be kept out of childrens' reach! An appropriate insurance has to be contracted before the first flight! Do not fly above people or animals.

Assembling step by step

This is a photo of the complete kit.

Quadroppm12 bausatz.jpg

QuadroPPM12 Kits are available in the shop

Here are the Shoplinks.

PCB assembly

  • The assembly is done according to the following mounting diagram, the PCB photos and the schematic.
  • The assembly is made with SMD-Parts. The list of materials shows the correct mounting order.
  • Follow the hints in the list of materials.
  • The programmed microcontroller (ATmega88 / ATmega168) and the crystal are already mounted.
  • In the new Version (with microcontroller ATmega168) all parts (except R3) alre already mounted.

Mounting diagram / PCB Photo (magnified)


Attention! In Revision "C" of the PCB a small change for future applications was made, as shown in the following picture:


The small pad above the channel-1-pad (third from the left, near "R1") should not be connected to channel1 without using an alternative firmware.



List of materials

Quantity Reference Value Hint
1 IC1 ATmega88 / ATmega168 already mounted
1 Q1 crystal 16MHz already mounted
1 C1 100 nF / 0805
1 R1 10 kOhm / 0805
9 R2-R3 330 Ohm / 0805
1 LED LED green / 0805 Observe polarity! Arrowhead on the backside of the LED points to the marked side (Cathode)! )
14 c1..c12, +5V, GND Socket for receiver
60cm K1..K8 Wire yellow, 0,14mm² 12x 5cm, for signal wires from receiver.
5cm 5V Wire red, 0,14mm² For +5V-wire to receiver.
5cm GND Wire black, 0,14mm² For ground wire (GND) to receiver.
20cm Heat shrink tube 14x 13..14mm, for receiver sockets.

The receiver is powered by the QuadroPPM12. For the interconnection to the receiver single wires are used which are soldered to the sockets. Take care that no solder comes INTO the socket. Isolate the wires with the enclosed heat shrink tube.

Configuration of the number of channels

Before connecting the QuadroPPM12 to a receiver you must tell the QuadroPPM12, how many channels are used. Every missing channel activates the error detection and prevents the copter from taking of. The configuration is done via four solder jumpers according to the following table:

A B C D Description
0 0 0 0 4 channels
0 0 1 0 5 channels
0 1 0 0 6 channels
0 1 1 0 7 channels
1 0 0 0 8 channels
1 0 1 0 9 channels
1 1 0 0 10 channels
1 1 1 0 12 channels
x x x 1 Update mode

Detection of signal loss

With solder jumper FS can be selected whether the detection of signal loss behaves "the classical way" (detection of too long or too short Impulses) or the receiver failsafe function is beeing processed.

Classical method

Classical method = solder jumper FS is open. This detection method is always active. Too short and too long impulses at the inputs are recognized as failure. The limits for the pulsewidth are between 0,8ms and 2,2ms. With this method 12 channels can be connected to the QuadroPPM12.

Processing of the receiver failsafe function

Processing of the receiver failsafe function = solder jumper FS is closed. When using detection method, you have a program a random channel of your RC system so, that it puts out an impulse with minimum 1,5ms. This equals the middle of the servo travel. This channel is connected to channel 12 of the QuadroPPM12. In this mode you must not connect a regular rc function to this channel or otherwise the error detection of the QuadroPPM12 will become active when the signal is longer then 1,4 ms!!!

LED blink codes

  • short LED impulse every second: correct servo signals detected.
  • long LED impulse every second: incorrect servo signals detected.
  • LED lights permanently: Update mode activated. The QuadroPPM12 waits for new firmware.

Update mode

By closing the solder jumper "D" the update mode is activated. Via a USB-Serial-Converter or a level converter for a serial port the Controller can be flashed. Connect the wires for 5V, GND, Channel 10 and Channel 11 to the receiver as shown in the update software which guides you through the procedure.

Quadroppm12 update s3.png

Firmware Updates can be found here: QuadroPPM12 Firmware Download


1.1 - 10/2010

First public release.

1.2 - 12/2010

- Bug with 12 channel receivers fixed. The Bootloader function was implemented after testing the firmware. This caused a bug: Channel 11 was permanently tied to ground, which prevents QuadroPPM12 from working with 12 channels. >> Download

1.3 - 03/2011 (newest version)

- Fixes jitter in the output signal. This problem was mainly reported in combination with Futaba receivers. >> Download