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Fatshark channel switching

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I am working on a project to use external Rx modules on Fatshark Transformer goggles.  My solution works with modules that have onboard channel selection, LaForge, etc., but I would like the option to use Fatshark 1.3 and 2.4 modules.  The problem is channel selection. 

Can anyone explain the circuitry in Fatshark goggles that allows channel selection with the buttons on the goggles? Could I construct something that would allow me to accomplish the same thing on an external board?



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Could I construct something that would allow me to accomplish the same thing on an external board?

If you mean you want to use FatShark's external vRx modules and do channel selection manually, then you can do it with a triple wide DIP switch like this:

ebay choices: https://goo.gl/GijFH7

The 3-bit binary code is used to change FatShark's seven channels that are available in each RF band. On modules with more than seven channels, the RF Band changes are handled by the existing double wide DIP switch that is mounted on the Fatshark module.

Connect one side (3 pins) of the triple wide DIP switch to ground. The other side goes to the module's CS3 {Channel Select bit 2}, CS2 {Channel Select bit 1}, and CS1 {Channel Select bit 0} pins (one switch per pin). The CSx pins are clearly labeled on the FatShark Module.

Each switch grounds (logic 0) the CSx pin when it is turned ON. For example, CH1 is 0-0-0 (ON-ON-ON), CH7 is 1-1-0 (OFF-OFF-ON).


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 Thanks for the help with the dip switches. That is certainly an option. 

I am wondering if there is a way to do the same thing with buttons instead of switches.  Essentially, I would like to select the channels by using up and down buttons in the same manner as on the Fatshark goggles. 

I would be using them with 1.3 and 2.4 modules with only 7 channels. 

Edited by Guytranspo
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The DIP switch is also available in a push button (or thumb wheel) form factor like this:


One of these would replace the entire triple wide DIP switch.

A fully electronic Up/Down button method will require some digital electronic design skills. That is to say, you will need to design a circuit that emulates the DIP switch's binary code.

Two things come to mind that could do the job, depending on your design experience.
 [1] Arduino + Your custom code: https://store.arduino.cc/usa/arduino-mini-05
 [2] CD40193 CMOS Binary Counter IC: http://www.ti.com/lit/ds/symlink/cd40193b.pdf

I don't have any schematics or code to offer, so you're on your own.


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