Help needed: Deviation and telemetry equipment

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30 Mar 2014 20:52 #21960 by jo-loom
To all experts:

I need some help and recommendations with regard to deviation running on Walkera Devo 12S to start using telemtry equipment for RC helicopters.

It would be great if you can answer my questions:

1) Is it generally possible to use Walkera WK-CTL01-D telemtry modules incl. Walkera receiver with full Deviation support?




2) Walkera is offering sensor solutions for temperature, voltage, rpm and GPS. Does any of you have a recommendation for a suitable current sensing module (approx. 0..50 amp)?

3) Have you even got a better recommendation for any kind of Deviation compatible telemetry equipment not causing a budget explosion? (IISI e. g. is well known). I like to at least monitor and log LIPO current, LIPO cell voltage, motor or rotor rpm, GPS and one or two temperatures.

Thanks a lot for any kind of help.
Johannes
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31 Mar 2014 04:26 #21963 by FDR
I'm not an expert at all, but here are my hints:

1. yes

2. AFAIK Walkera doesn't provide a current sensor, neither there is a current display, so all you can do is to get a 0.1 Ohm shunt, and connect it to a voltage sensor. This way you will get 0..5V display for the 0..50A range

3. We've got Spectrum telemetry covered preatty well, but I don't know if it would explode your budget...

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31 Mar 2014 13:10 #21965 by jo-loom
@ FDR:

Thanks a lot for your reply and the helpful information!

I will order a bundle telemetry module plus GPS sensor to start playing a bit.

May I ask some additional questions? As background: I got a lot of experience in micro electronics - so it wont be any problem for me to assemble hall effect current sensors or any other kind of converter to 0..+5V input signal range.

1) The by far most relevant parameter of interest is consumed battery capacity (main current x time). Is there any chance in deviation to get such figure on the main display e. g. by using a timebased integration of the 0..+5V spare input as equivalent to 0..50A?
Even better would be the possibility to add alarm thresholds.

2) There is a great telemetry system in the market (IISI / Switzerland) just for the basic functions operating RC helis. It allows monitoring of battery capacity, battery overall voltage and battery cell voltage - everything combined with configurable thresholds and acoustic alarms. In addition you can configure a trigger condition such as main current > x amps.
Are there any plans or opportunities to add similar functionality in future deviation releases? In my opinion they would further increase usability and "unique selling points" of deviation.

3) To me it appears relatively simple implementing a kind of data logging functionallity based on already given modules.
It would e. g. mean to once define a simple loggng table (channel names, sample rates, scaling, trigger condition). During operation the software would store a ASCII (or similar) file with all received telemetry data - especially parameters of interest such as GPS, speed, rpm,...
Is it imaginable to go for such feature in future deviation releases?

Thanks a lot for all your help,
Johannes

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31 Mar 2014 17:33 #21970 by FDR
1. ATM no, because you can't do calculations on the telemetry data. Of course you can configured alarms, but only for the pure telemetry data. However we have something similar: a throttle dependent timer, but that is not telemetry...

2. We have tresholds and alarms on telemetry data, but you can't trigger anything else but the alarm.

3. We already have data logging of selected telemetry data into files. I think they are binary, but you can use a simple utility to convert them into readable format. Furthermore it can log channel values, stick positions, switch states, timers with it too...

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31 Mar 2014 18:16 #21973 by PhracturedBlue
Replied by PhracturedBlue on topic Help needed: Deviation and telemetry equipment
Implementing a battery-usage value would be pretty cool, but probably very limited functionality. Unlike voltage, current is not often readily available on receivers. It would need to be tied to a timer, and would need a reset capability. It will add a significant amount of complexity to implement. If someone wants to do it, I'll likely be willing to incorporate it, but I'm unlikely to work on it myself.

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31 Mar 2014 18:17 - 31 Mar 2014 18:17 #21974 by Hexperience
Replied by Hexperience on topic Help needed: Deviation and telemetry equipment
Now that PB is close to finishing work on the Universal module (if not finished) he may start looking at FRSky compatibility. (MAY, I have no idea what he's up to... :) )

I've been able to bind my D8 frsky receiver. At this point there is no telemetry in deviation for FRSky, but, FRSky does have a current sensor, among many other sensors. They are generally pretty affordable.

I have a Spektrum TM1100 module and I do get telemetry back from that, but there are some weird readings. (Altitude continually increases even though there is not ALT sensor connected. And my voltage readings "flicker") There is a new spektrum current sensor coming out, but I haven't seen a price for those yet.

Walkera telemetry has been very reliable for me so far. The only thing I don't like is that just to get the basic RX and Flight pack voltage, you have to buy a module. Not tooooo much of a pain, but if all you want is RX and 1 external pack voltage, then it's over kill. (FRSky and Futaga have those built into the RX, no module required)

I use my walkera telemetry for ESC temp, flight back voltage, RX voltage and Rotor Head RPM.

There are 10 types of people in this world. Those that understand binary and those that don't.
Last edit: 31 Mar 2014 18:17 by Hexperience.

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