View Single Post
Old Feb 14, 2010, 05:17 PM
phil_g is offline
Find More Posts by phil_g
Who let the dogs out?
phil_g's Avatar
Pontefract, Yorkshire, UK
Joined Jul 2007
1,267 Posts
Originally Posted by phil_g View Post
I have a pre-prod Frsky 2-way for trials, just awaiting connection info for the telemetry and the uncommitted serial comms channel... quite excited about this as it will open up all sorts of avenues for experimenters... will report back in due course.
Ok, heres a taster of the new system, its early days and theres much more to come:

I have the pre prod Frsky telemetry set on trial at the moment, I've had the system a few days but have only just got the datasheets through from Frsky as its New Years holiday over there. The module and receiver for the moment comprise two uncased boards, the most noticable change over the existing Frsky set being the additional connectors.

The receiver has four return channels, two of which are analogue to digital converters, reading (in their raw state) zero to 3.3 volts, and having external connections to devices in the model. The third is internally connected and reports bit error rates as seen at the receiver.

The fourth channel is to me the most interesting as it is an uncommitted RS232 serial stream which could be used for all manner of experiments and data. It has a fixed baud rate of 4800 which matches the NMEA GPS standard, which I guess was intentional.

The telemetry channels feature configurable alarms triggered by threshold voltages, ie an "alarm if above V" and "alarm if below V" can be set on each channel, and with three levels of alarm. The configuration is controlled by a protocol of fixed-length packets, and PC software is included to aid this process. The threshold configuration is sent to the receiver from the transmitter module which is connected to the PC serial port.

From an R/C flying point of view, its (as you would expect) very similar to the existing Frsky, but there are a few changes wrt range check procedure, failsafe setting and of course the alarms - which incidentally are simple audio, remember this is a module and has no display, it simply 'beeps' & sends serial data to a terminal. In my case, initially this is a notebook running a comms program, but I do intend to build a pic+lcd module into a small box which will mount on the tx. The failsafe is set by briefly pressing the bind button on the transmitter (not the receiver, as per the existing Frsky) which means you can actually set the failsafe in flight - this is unprecedented as far as I'm aware - so you can shut the throttle, trim the model for stable circular flight, dab the button and thats your failsafe!

The set is quite a bit more complex than a traditional outfit and clearly a complete test is far more involved, requiring external equipment and cabling so I think it will take a little longer to report back, please bear with me.
phil_g is offline Find More Posts by phil_g
Last edited by phil_g; Feb 14, 2010 at 05:45 PM.
Reply With Quote