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Build your own telemetry sensors.


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  • 2 months later...

Hi Chris,

Seems like I'm very late to the party. Just started with Arduinos a few weeks ago, and am building a vario sensor based on the OpenXSensor page.

Do you have any of the PCB boards left? Don't worry if not.

Was there anything in the magazine article that you've not covered here. I've tried to get hold of a back issue, but there doens't seem to be any available.

Many thanks.

David

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Posted by David Wilkinson on 27/06/2020 13:29:28:

Hi Chris,

Seems like I'm very late to the party. Just started with Arduinos a few weeks ago, and am building a vario sensor based on the OpenXSensor page.

Do you have any of the PCB boards left? Don't worry if not.

Was there anything in the magazine article that you've not covered here. I've tried to get hold of a back issue, but there doens't seem to be any available.

Many thanks.

David

Hi David

Yes I'm sure I have PCBs still. Certainly the fully functioning but incorrectly printed ones. Almost certainly some correct ones too. If I can dig out the mag I could photocopy the article and include that as well.

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  • 9 months later...

Resurrecting an old thread, I have a question for other sensor builders and an update on the openXsensor software. 

 

1). Has anyone has success with any openXsensor based telemetry with FrSky Archer / Access receivers? I'm really struggling with one unit working (but sometimes not) and 4 others that don't work at all. 

 

2). I've downloaded the latest version of openXsensor, to find that it now includes a 'configurator' program that really simplifies the setting up. If you're still interested then this looks well worth investigating. 

 

Screenshot_20210413-181158.thumb.jpg.df3b8431efccedb0e8ae4f1795cc37ac.jpg

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Chris, I can't see that the sensors are handled any differently on Access receivers, I've got a couple of SR6 and 8s running Access with Neuron escs and lipo sensors.  It's a while since I set them up but I'm pretty sure that they hooked straight up with no issues.  I'll see if I can find the log files and take a shufty to be sure.

edit - I don't appear to have any logs to hand, sorry! I'm pretty sure that I checked they were working, otherwise I'd have had low voltage warnings screaming away when I set them up!

Edited by Bob Cotsford
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  • 1 month later...

I just happened to run across this forum. I’ve always been interested in onboard sensors. I’ve used the Spectrum vario in my sailplanes and it works. I built my own airspeed sensor a few years ago using a pressure sensor chip, an op amp and a bar graph. Then I did an onboard video recording of the readings. 
You can see a video and photos on RCgroups. Just search my user name “Slope445”

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On 13/04/2021 at 18:13, Chris Bott - Moderator said:

Resurrecting an old thread, I have a question for other sensor builders and an update on the openXsensor software. 

 

1). Has anyone has success with any openXsensor based telemetry with FrSky Archer / Access receivers? I'm really struggling with one unit working (but sometimes not) and 4 others that don't work at all. 

 

2). I've downloaded the latest version of openXsensor, to find that it now includes a 'configurator' program that really simplifies the setting up. If you're still interested then this looks well worth investigating.

You may be having trouble with the voltage levels out from the Rx. I had trouble with a D8 receiver running my D16 firmware. The high logic level voltage was not high enough for the openXsensor to see as a logic '1'. FrSky SPort devices use a transistor buffer/inverter, so only need to see around 1 volt.

I did a change to the openXsensor code that allows the Arduino analog comparator to be used for the SPort input. This recognises anything over 1.3V as a logic high.

You would need to compile the openXsensor code with the appropriate pin selected as the SPort signal (IO7 I think), and re-wire the hardware so the SPort signal goes there.

This makes the openXsensor more compatible with the SPort hardware.

 

Mike

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  • 5 months later...

Sorry about the lateness but just decided to make some GPS sensors to work with Frsky X receivers and noticed this thread . I believe there an article in 2019 RCM&E with an article that might start me off , can someone confirm for me the month or a photocopy if not available ?

I have managed to read GPS data to arduino uno and run the Frsky Sensor to test whether the data is read by TX16S telemetry ( it was) just now need to hook them together but not sure where to start. If i had got into this back then I would have had some of the sensor boards but probably way to late for that .

There is sketch from googling that says it does GPS to Frsky telemetry but i could not compile at all and too thick to work out why . Was looking for location, height ,speed from the GPS and maybe some pack info such as current ( worked out volts easily enough) .

Hoping someone can help .

Edited by Brian Dorricott 1
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Hi all

Thanks Chris B for pointer to original magazine article that's all up and running on breadboard except the current sensor seems to out of stock everywhere but I have tested the port with a varying voltage and it will work but need calibrating . Anyone got a spare ASC758LCB they could sell ( RS out of stock )  ?

Using the configurator I built the GPS version to log location, height and speed again on breadboard to the RM TX16S SD card and that all worked really well all I need now is something to plot the .csv log onto as i'm not keen on Google Earth which works but is a faff , preferably free alternative to Google that I can plot the flight path on ?

For those interested in technical aspects I built the GPS and voltage/current circuits on Arduino Nanos with a Neo 6M for the GPS ( only 4 wires and a resistor) and for the voltage/current/pressure with a BMP180 and the voltage resistors on Veroboard . When its all tested and calibrated I will heat shrink it for protection .

If anyone is interested I can email .ino file and a connection instruction but it is all in the description .h file for OpenXsensor anyway .

For those interested in this topic there is a nice standalone circuit using an Arduino that writes to an SD card instead for those who don't have telemetry on there radio gear . I think for larger models the CAA may demand some form of logging soon but lets see.

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  • 1 month later...

Sorry to ask again but has anyone got a spare hall effect sensor for this project as they seem unavailable everywhere ACS758 LCB-50u or 100u . Alternatively is there a substitute that could be used ? Bit stuck now for the current sensor Banggood do something but they are all -100b or 50b bi-directional ones that dont measure down very low .

heres hoping someone has a spare in the bits box .

 

Cheers

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I think a bi-directional one would do, Brian? If memory serves me correctly, you'd just need to set the offset voltage to suit, probably to half supply volts?

 

A quick eBay search found this in the UK (and plenty offered from China).

https://www.ebay.co.uk/itm/CJMCU-CJMCU-758-ACS758LCB-050B-PFF-T-Linear-Current-Sensor-Hall-Current-Module-/163353797118?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=710-127635-2958-0

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If you're quick, RS have a (very) few ACS758ECB-200U in stock. These days you have to adapt to whats available ?

https://uk.rs-online.com/web/p/motion-sensor-ics/7248739       (ignore their 'motion sensor' mistake)

The advantage of RS is that you know you're getting genuine manufacturer parts, not knock-off clones!

 

Edited by Phil Green
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  • 1 year later...

I've just discovered that the openXsensor firmware has some errors in it when sending FrSky SPort data.

1. Altitude and vertical speed are transmitted as fast as possible where there should some rate limit such as only every 100mS or 200mS.

2. Sensor items that are polled but don't have any new data should reply with a packet of all zero bytes, but they actually respond with the first byte not zero, so equivalent to always sending data.

 

The combination of these two problems is an openXsensor can request the Rx to send more data than the radio link can handle, particularly for receivers such as the G-RX6 and G-RX8 that also have internal sensors that send data. This will result in loss of data so some sensors may not be able to return data very often.

 

Mike

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