@ravid824 wrote:
I have many R/C plans and copters that uses the Frsky receivers. All are operated with one radio transmitter. For some of the copters I needed more than 8 channels solution. I wanted to continue using the same radio transmitter that I love and keep using the CPPM receivers installed on the plans and drones. I couldn't find a good solution that fits my needs. I am an hardware and software engineer for more than 30 years and I developed many controllers and also wrote the firmware. So I decided to develop my solution described below.
I developed a solution which I called PPM merger which is a perfect solution to upgrade my transmitter/receivers to 12 channels PPM.
I thought that this solution might interest other R/C users and I am selling the solution on eBay (search for "PPM Merger"). The price is my cost price since I produced small quantities.
The document in the link below thoroughly describes the product and how to upgrade and set your radio controller with connection diagrams, as well as a few flight controller setting examples.
https://www.dropbox.com/s/bnu3j0wvz6ztciz/12ChannelsPPMsolution.pdf?dl=0
I will also provide any professional technical support as required.Product Description
ER9X based RC transmitters such as Frsky Taranis , Turnigy 9X (the older models), Turnigy 9XR Pro, FlySky FS-TH9X, etc. support 16 RC channels, however, the transmitter modules such as FrSky DJT/DFT or OrangeRx DSMX/DSM2 only support 8 channels. Even though the RC transmitter can stream 16 channels, the transmitter modules ignore channels 9-16 and solely utilize channels 1-8.The PPM Merger cascades two 8 channels receivers PPM streams (PPM1-IN and PPM2-IN) and generates a 12-channels PPM-OUT single stream (PPM can only support up to 12 channels).
The PPM-OUT is a clone of the input streams in the appropriate order, PPM2-IN channels 9-16 follows PPM1-IN channels 1-8. The sampling and replication of the PPM input streams is very accurate (0.5 uSec resolution).
The PPM merger also has 4 PWM ports that can be directly connected to servos (channels 9-12). These PWM signals are emitted in parallel to the PPM stream.Using PPM Merger provides the following advantages:
Using your standard receiver/transmitter modules (the well-known Frsky D series or similar)
Save flight controller UART port
Most flight controllers reserve the UART port for the S-BUS connection though there are limited UART ports. With a PPM connection, you are freeing the UART port for other important connections (telemetry, GPS, OSD, Radio telemetry etc.)Fit 12 channels directly into the flight controller and leverage on flight controller capabilities to control channels 9-12 (such as gimbal servos and other transmitter switch controls)
Compatibility with different brands of transmitter/receiver sets
Image may be NSFW.
Clik here to view.Compatibility
The PPM Merger was tested with several receiver types:
· Frsky 4Dr-II
· Frsky D8R-XP
· Different brands of PPM encoder module (convert any 8 PWM channels receivers to one CPPM signal). Check the link below for more info:
http://ardupilot.org/copter/docs/common-ppm-encoder.html
The PPM Merger module output stream was tested and run smoothly with the following flight controllers:
· Pixhawk (Arducopter 3.4)
· Naze32 (Cleanflight 1.13 and Betaflight)
· SP Racing F3 (Cleanflight 1.13)
Other technical specifications:
Supply voltage: 4-5.5V
Weight: 4 grams
PPM in sampling accuracy: 0.5 uSec
PPM out Replication accuracy: 0.5 uSec
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