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Posted by benzo99 | Nov 20, 2016 @ 03:19 PM | 23,193 Views
This article is still a rough draft because I'm still working on adding all the details. Please come back when it's finished!!

I decided to upgrade the stock Tx and Rx for my Cheerson CX-20. I used a Turnigy 9XR Pro transmitter with the DIY multi-protocol module and an FrSky X8R receiver, but this post could apply to other Tx and Rx hardware as well.

Step 1 - Replace the receiver
Replacing the stock 8-channel receiver is pretty straight-forward. I used the X8R because it supported telemetry via S-Port (see my other blog post for details about getting that to work), works with the multi-protocol module, and seems to have a good reputation. I could also set the receiver up to support 16 channels meaning I had more options.

You could simply wire in the new receiver as a direct replacement by moving the stock wiring to the new receiver, but I decided to configure the X8R for D16 'Mode 4' which meant I had channels 1-8 on the SBUS port, and channels 9-16 on the PWM pins.

Because the CX-20 stock FC does not support SBUS an additional converter is needed to convert the Rx's SBUS output to PPM for the FC.

Part's needed:
  1. FrSky X8R Receiver
  2. FrSky SBUS to CPPM converter

Installation steps:
  1. Remove the existing connections from the receiver to the flight controller
  2. Connect the power connector from the PDB (was connected to 'B' on the stock Rx) to channel 8 on the X8R
  3. Connect the CX-20's underbelly S1 connection to channel 1 and S2 to channel 2 on the X8R
  4. Place a
...Continue Reading
Posted by benzo99 | Nov 19, 2016 @ 04:38 AM | 21,974 Views
I decided I wanted to add telemetry capability to my CX-20. I don't have FPV (yet) and didn't particularly want to add external 433MHz transceivers for telemetry, so wanted to do it on the transmitter, as can be done with the Taranis and other transmitters.

I'm lucky enough to know hpnuts (Pascal) through work, and on his advice I started to look at the Turnigy 9XR Pro transmitter, along with the 4-in-1 multi-protocol transmitter module.

With some help I got this to work fairly easily.

Step 1 - Add a power module (optional)
A power module allows the APM flight controller to get information about battery voltage and current. APM power modules for the CX-20 can be found cheaply on eBay. I did this part first because it can be done independently of everything else - you can just use the data for failsafe setup.

The module required a minor modification to be compatible with the CX-20's flight controller - you have to replace the six pin micro-JST plug with a 3-pin plug. This process is well documented in Spy's Useful Info post. I used these 3-pin connectors.

Once the module is installed it needs to be calibrated.

Step 2 - The transmitter
Obviously the stock transmitter won't do. I needed an upgrade. As I mentioned above, the Turnigy 9XR Pro fit my budget and seems to do everything I want. I got mine from Hobby King for 49, but I've seen it as low as 39. You need to add a battery and a module.

Upon receiving the transmitter I flashed it to the latest available ...Continue Reading