Turnigy 9x - Frsky DHT Module Telemetry Hack without RS232 Converter

I'm having this transmitter for quite so long which i bought from a friend. All this while it just been used by my son to control his RC Rover as i don't trust the stock Tx module on the transmitter for my flying. Until i build my tricopter and then my quadcopter. Flying a multirotor need us to be aware of the on board voltage while flying to a void any mishaps.
As i have done a mod to a friends Flysky TH9x with a Frsky module giving him a means to monitor his voltage on board through telemetry, i decided to mod my Turnigy to do the same but this time using a Frsky DHT DIY module.

WARNING: THIS MODIFICATION INVOLVES SOLDERING SMALL THINGY AND MAY CAUSE PERMANENT DAMAGE TO YOUR 9X BOARD.

This is the Frsky module that i used - FrSky DHT 8ch DIY Telemetry Compatible Transmitter Module
I have been using it in my Futaba 7CHP for quite some time and i'm very happy with it. It can be used to transformed any of your PPM transmitter into a new 2.4GHz Tx provided you can find where the PPM signal are in your transmitter.
For it's price, this is a must have upgrade with a reliable frequency hopping technology.

I get this readings on my Turnigy 9x screen after the mod

I started with all the basics mod which i have done here to my friends Flysky TH9x. This includes:

- ER9x mod.
- Backlight mod.
- Speaker mod.
- Haptic feedback mod.

Telemetry Mod Without RS232 Converter
This mode includes working with small traces on the board and soldering small component. Proceed at your own risk.

On the Board -
To run the FRSKY build of er9x you will need to make some modifications to the hardware in your radio. These modifications require soldering of small tracks on the radio circuit board, as well as solder two little wires on two of the CPU pins. This modification will re-route two of the switches (THR and AIL) and allow the Atmega 64 to receive telemetry data on the pins where these switches were formerly connected.

http://openrcforums.com/wiki/index.php/File:Frsky_telemetry_mod_overview1.jpg

On the Module -
For the module mod i had refered to this post -
http://www.rc-cam.com/forum/index.php?/topic/3827-er9x-hacks/

How my mods looks like

Heat shrink opened for the module mod

Two wires soldered to the board after i cut the mentioned trace on board. I routed the wire to prevent any stress on the solder join. Resistor inside heat shrink.

PPM wire from module soldered to the board.

I decided to follow the guide in placing my bind button/led.

I empty up the stock module case and place the DHT module switch here. It is concealed nicely and accessible. The antenna connector just hot glued in place.

Shows where the module are placed with velcro and various connectors for ease of later maintenance.

Before putting it all together, just make sure its working. At least you can switch it on. Only then you can proceed. If you are not using the FrSky er9x firmware, you will get a warning on start up that the AIL and THR switch is on. Flash your tx with the FrSky er9x firmware will solve this.

Next, you will need at least this RX and this sensor to get the telemetry data display on your tx and don't forget to set the er9x to display the data on screen.

Enjoy modding ...