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My FrSky telemetry project

PostPosted: Tue May 18, 2010 5:03 am
by RCModelReviews
In this topic, I'll be presenting information on my telemetry dashboard and airborne hub projects.

These are designed to use the FrSky 2-way module/receiver system (due out this month) and will allow you to monitor such things as your model's speed, altitude, distance, heading, rate of climb/sink, receiver battery voltage, e-power battery voltage etc.

I'm using PIC processors because they're cheap and can be had for free (all you have to do is ask Microchip for sample units), plus there's a free C compiler and workframe (MPLab) available for download from the microchip website.

The transmitter-end is where the dashboard goes. Right now, my prototype system needs less than 20 components (including the LCD).

The receiver end is where the "hub" goes. This is also based on a PIC processor and allows the connection of a large number of sensors and other devices if you need to. Initially, I'll just be using a simple GPS module which will provide almost all the information required. Shortly I'll replace the current GPS module with one that has a helical antenna and that should provide much better results in aerobatic aircraft where the orientation of the model may be far from level most of the time.

Rather than use the analog inputs that FrSky provide, I'm going to use the processor in the hub to measure the battery voltages (which means you'll be able to get a voltage for each cell of a multi-cell LiPo if you want). Using this method, I'm also able to provide a good measure of data compression and pre-processing so as not to overload the limited bandwidth of the telemetry downlink channel.

Other sensors planned are a pitot-based airspeed sensor, a barometric altitude/variometer sensor, a tachometer and a G-sensor.

Although this system is designed primarily for the FrSky, it is flexible enough that it will also be adaptable to work with other telemetry-enabled RC systems if/when they appear. If there's enough demand I might even reverse-engineer the Hitec one too.

I will be publishing full project pages on the RCModelReviews website but this part of the forum will be used to keep people updated with any day-to-day progress and to answer any questions you might have.

Any questions?

Re: My FrSky telemetry project

PostPosted: Tue May 18, 2010 6:16 am
by jomarx
The only thing I can think of is : When do we start? :D

Seriously, this is a wonderful project Bruce! Good luck and keep us posted.

Re: My FrSky telemetry project

PostPosted: Tue May 18, 2010 7:00 am
by RCModelReviews
I've already started :-)

I'll upload some pictures in the next day or so.

Re: My FrSky telemetry project

PostPosted: Tue May 18, 2010 12:56 pm
by GeicoGecko
Have you got any details or links on the modules?

Re: My FrSky telemetry project

PostPosted: Tue May 18, 2010 9:54 pm
by RCModelReviews
I'm only using a pre-release module/receiver at the moment and the release models will be slightly different.

Re: My FrSky telemetry project

PostPosted: Wed May 19, 2010 2:39 am
by beau0090_99
Bruce,
I didn't have time to read what you just wrote, but did you see this at HobbyKing? It is for the Quantum, but I wonder if there is any likelihood that it might work with FrSky. This hobby is really opening up to the poor folk like myself :-)
Curtis

http://www.hobbycity.com/hobbycity/stor ... duct=11251

Re: My FrSky telemetry project

PostPosted: Wed May 19, 2010 4:27 am
by RCModelReviews
It wouldn't work "off the shelf" with the FrSky but it'd almost certainly be possible to reverse-engineer it to work with the hub unit I'm building that connects to the FrSky receiver. If there's demand I'll see what's involved in reverse-engineering the Eagle-Tree sensors too.

Re: My FrSky telemetry project

PostPosted: Wed May 19, 2010 7:03 am
by RCModelReviews
For those who haven't seen them, here are the prototype (test) transmitter board and receiver board from FrSky. These aren't what they'll be shipping but they're what they've given myself and a handful of other developers to play with in the meantime.

The other blank PCB is the one I designed and etched for the dashboard project. I'll post some pictures of it with the bits on later.

Re: My FrSky telemetry project

PostPosted: Wed May 19, 2010 9:38 am
by kgfly
Couldn't see a way to monitor the thread without posting so here's a post. Looking forward to seeing this system evolve.

Re: My FrSky telemetry project

PostPosted: Wed May 19, 2010 9:52 am
by mr.sneezy
Hi kgfly, ditto on the monitoring the thread. I hope a few other familiar names pop in too for the ride :D