FrSky DHT Alternatives

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PaulJ
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Re: FrSky DHT Alternatives

Post by PaulJ »

Phil_G wrote: 18 Dec 2019, 13:01 Its possible that leaving it on killed the module Paul. The PA may have simply overheated. Or, heres a thought, while the battery is up everything is hunky dory but as it slowly discharges, a relatively big battery with a light load will be in the brownout region for a prolonged period of time, during which unpredictable stuff happens - generally switching becomes linear and therefore dissipates a lot more heat, things stop oscillating and a PA can draw large DC currents, the processor will become erratic and might lock the PA on permanently (normally MU is 10% or less). A brief brownout is harmless but yours would have been held there for hours, its just an opinion but I expect thats why. I've accidentally left trannies switched on overnight but never had one drain the battery fully.

Or, maybe the PA just got hotter & hotter with being left on for hours inside a sealed enclosure. I dont know how OrangeRx spec their boards but I would have thought continuous operation would be ok.

Since its a 'recent conversion' so presumably a new/unused module, it could simply be ELF, it happens, thankfully very rarely, but it happens... :D
/2p

Phil
PS presumably it had an aerial? :D
Many thanks Phil, I am just glad that it was my fault and not a "failure" as such because that would shake my faith in Orange modules! 'Pity though but fortunately HK still have them in stock. Will your 2+1 Digispark still be OK or will that be fuggered too? The battery was only "storage charged" to start with so that would be why it went so completely flat overnight...... and yes, it had an aerial!

Paul
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Bo Edstrom
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Re: FrSky DHT Alternatives

Post by Bo Edstrom »

Just curious:

Would it be possible to have transmitter power shut down via software code for the encoder based on DIY More Pro Mini Strong board and maybe some additional hardware, so a transmitter "forgotten" On will not ruin anything? (encoder or 2.4 GHz RF board or anything else)

I'm so used to my modern Futaba, that shut down after a user selectable time if transmitter is left On (forget to switch it Off). The inactivity function just not alarm with a sound but also Power Off the transmitter after user defined time of inactivity.

It is not that uncommon to "forget" a transmitter On (I sometimes forget).

/Bo
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Shaun
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Re: FrSky DHT Alternatives

Post by Shaun »

That's not a feature I would want.
I want to be in control of when my Tx is turned off, not software and the inactivity timer beeps to let you know you've had a senior moment. ;)

Shaun
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Mike_K
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Re: FrSky DHT Alternatives

Post by Mike_K »

Bo Edstrom wrote: 19 Dec 2019, 15:16
I'm so used to my modern Futaba, that shut down after a user-selectable time if the transmitter is left On (forget to switch it Off). The inactivity function just not alarm with a sound but also Power Off the transmitter after user defined time of inactivity.

/Bo
Hi Bo

The big difference between our conversions and modern Futaba (and other) transmitters is that we use a proper mechanical on/off switch - usually the original slide switch, whereas most modern transmitters have a "soft" switch" - you press it for on and press again for off.

With modern transmitters, when you turn them off, they don't turn off immediately, but after a few seconds delay. I noticed this years ago while doing a failsafe test with a JR transmitter by turning it off, the power LED stays on for 3 seconds and servo's don't go to failsafe for up to 4 seconds. I found it was the same on Spektrum and Futaba transmitters as well (and probably others).

I contacted Spektrum technical help to find out why and the reason for this is that modern transmitters are more like mini PCs, they are writing to memory all the time with telemetry data etc and they delay turning off the transmitter until it's ensured that all the data is written properly to the SD card or wherever the telemetry is being stored, otherwise it could corrupt the memory. So they already have an electronic switch to do power on and off, so can offer the option of auto power off after inactivity.

Obviously we could replicate this electronic switch function, but do we really need it? It's just another thing to go wrong. On my conversions, I've set the inactivity alarm fairly aggressively at 1 minute inactivity. It does mean it sometimes sounds if I'm waiting to take off while somebody is landing or if I'm flying "guided" free flight where you don't touch the sticks for more than a minute, but I can live with that. But it does mean I've not yet left it on by mistake in my workshop as I can't get out of my workshop within a minute.

Mike
Spike S
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Re: FrSky DHT Alternatives

Post by Spike S »

I acknowledge this is a slight sidestep for the Topic and apologise accordingly.
Having been involved with accident analysis and various working groups to determine more appropriate cockpit warning sounds, in Human Engineering terms, a Tx alarm while flying may not always be perceived for what it is. One of my members is a very accomplished helicopter aerobatics exponent (each to his own). One day he was flying quite aggressively and became distracted and annoyed by someone in the pilots' box making loud beeping sounds. He may then have encountered the well known aviation accident-chain affliction of "Press-on-itis". Only after examining the smoking hole in the ground where his sophisticated machine had rekitted itself did he realise that the noise was his own Tx low battery alarm !
Overheard on too many cockpit voice recordings: "What the *** is it (the computer) doing now ?"
Not quite the same as leaving a Tx on in the workshop but it does involve the same part of the brain and those naughty little Ergo Gnomes. :evil:
Spike S
(Tune for maximum smoke)
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Bo Edstrom
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Re: FrSky DHT Alternatives

Post by Bo Edstrom »

Shaun wrote: 19 Dec 2019, 17:47 That's not a feature I would want.
I want to be in control of when my Tx is turned off, not software and the inactivity timer beeps to let you know you've had a senior moment. ;)

Shaun
In the best of worlds we do not forget things. I'm not that forgetful but sometimes it happen, it is just human regardless of age.
Since itr can be a risk a DIY More Pro Mini Spark board can be "dead" if transmitter is by accident left with Power On until battery is drained, it would be nice if it was some technical workaround for this scenario. I have never had a commersial transmitter fail because of drained battery. Maybe it is a thing we have to live with that can not be fixed when using DIY More Pro Mini Spark board?

/Bo
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Mike_K
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Re: FrSky DHT Alternatives

Post by Mike_K »

Spike S wrote: 20 Dec 2019, 14:58 I acknowledge this is a slight sidestep for the Topic and apologise accordingly.
I thought the whole idea of the forum was to go off-topic, but I might be mistaken :)

Back to the alarms. I think it was a transmitter design flaw to blame for the guy who crashed his heli due to low battery level. While detecting the remaining battery capacity is not easy, it needs to ideally alarm with more than an average flight time left, say 15 minutes. When an alarm goes off you can't always land immediately, it often takes me 2 -3 minutes to come down with full crow braking when thermal soaring and you've caught a boomer. But checking your battery level during pre-flight checks is a thing of the past since as 2.4GHz and Lipo/Li-ion batteries give you hours of run time, more than enough for the longest of flying sessions.

And if his transmitter had haptic feedback (i.e. it vibrating like a mobile phone) then he would have known it was his transmitter doing the beeping.

As for alarms going off on the flight line, it is a contentious issue. You get people complaining about other peoples transmitters beeping and then their transmitter starts talking! I think audible alarms have their place as long as they are easy to differentiate between and don't go off too often. But having said that my transmitter is always beeping at me, powering on with the throttle open or trims not centred, count down timer etc. The alarms have stopped me doing something stupid, but haven't crashed me yet, so on balance, I think they are a good thing.

Mike
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Phil_G
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Re: FrSky DHT Alternatives

Post by Phil_G »

The sparkie should be fine Paul :D
Bo Edstrom wrote: 19 Dec 2019, 15:16Would it be possible to have transmitter power shut down ... so a transmitter "forgotten" On will not ruin anything? (encoder or 2.4 GHz RF board or anything else)
That was just an 'off the top' thought at the time, it may not have been anything to do with the low battery Bo. If it was a new or previously unused module it could just be Early Life Failure, which can happen very occasionally. We just dont know, but I think we should keep this one failure in perspective - when you think about how many hundreds of failed Spektrum RF boards have been changed out by Horizon Hobby... :?
Bo Edstrom wrote: 20 Dec 2019, 16:23Since it can be a risk a DIY More Pro Mini Spark board can be "dead" if transmitter is by accident left with Power On until battery is drained, it would be nice if it was some technical workaround for this scenario.
I think you're working around a non-existent scenario Bo. Many of our projects are permanently running 24 hours a day, every day, and some have been running for years. I use DIY-Mores in home-automation, alarms, solar charge monitors, etc, all permanently powered. I have some running directly from solar with a supply thats up way above dropout and down below brownout every few minutes with the panel voltage, I've left trannies switched on many, many times Bo and I have never ever had single DIY More board fail under any circumstances. They brown out cleanly, the 328P and my PIC chips too are designed to accommodate that. One project was Steve Burns' F5B lap scoring system which uses special encoders with Frsky modules powered up all day long, throughout the racing season. Touch wood, I suppose my first failure (in hundreds) would make me feel differently, have you had one fail?
Cheers
Phil
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Bo Edstrom
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Re: FrSky DHT Alternatives

Post by Bo Edstrom »

Thanls for the answer Phil, DIY More Pro Mini with P328 microcontroller should cope fine with empty battery then in scenario discussed now, great.

In PaulJ's case it was his Orange 2.4 GHz module then that did cope with the sitation if I understand correct, when transmitter was left turned On and battery became empty.

It is good this came to surface (at least for me).
- DIY More Pro Mini with P328 microcontroller should cope with the scenario.
- Orange 2.4 GHx module may not cope with the scenario, at least the module PaulJ had.

With risk of asking another stupid question, is it only a 2.4 GHz modules that is at risk to fail in this scenario with transmitter empty battery?

I think I got little confused about the question that was aksed here previously …"Will your 2+1 Digispark still be OK or will that be fuggered too?" and then the answer to that question was "The sparkie should be fine".
I know that much that Digispark (sparkie) is another encoder board. So I thought it might perhaps be some "problem" in this scenario with DIY More Pro Mini boards (but Digispark boards is fine).
But it is actually a Module problem then (not a encoder board problem, that I thought).

The reasion I'm interested in this is because I personally do not want to use any component in a converted transmitter that can have the result mentioned just because battery was empty.

/Bo
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PaulJ
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Re: FrSky DHT Alternatives

Post by PaulJ »

By way of an update........ I think it would be too much of a coincidence that the module should have failed just at the time that the battery went flat and I think Phil's explanation was probably correct. I had a spare Orange DIY Module (which had been destined for a different transmitter) and have now replaced the failed module. The Digispark was indeed OK and the transmitter is now working again as it should.

This thread has gone a bit off topic so pictures will be in a new thread....

Paul.
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