New Lemon transmitter module, DIY & JR formats

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Dave McDDD
Posts: 18
Joined: 28 Apr 2020, 19:37

Re: New Lemon transmitter module, DIY & JR formats

Post by Dave McDDD »

The blinking brownout light activates when using that battery, plus other batteries, with or without a switch, plus other ECSs. Conclusion? It's not a bad battery. It's not a defective switch. There is nothing wrong with the power being fed to the DSM2 receivers to cause the brownout light to blink. The brownout light does not activate when using any of these batteries or ESCs with any other transmitters except for the Lemon DIY and Plug & Go modules.

If any of these DSM2 receivers are bound to either of my two Spektrum DX5e transmitters, the receiver starts up with a solid light.
If any of these DSM2 receivers are bound to either of my two Multi-Protocol transmitter modules in either Taranis, the receiver starts up with a solid light.
If any of these DSM2 receivers are bound to either of my two Spektrum "Hack" transmitter modules in either Taranis, the receiver starts up with a solid light.
If any of these DSM2 receivers are bound to my Orange JR type transmitter module, the receiver starts up with a solid light.
If any of these DSM2 receivers are bound to my Orange Futaba type transmitter module, the receiver starts up with a solid light.

Again, the ONLY time these DSM2 receivers startup with a blinking brownout light is when they are being controlled by any of the six Lemon transmitter modules. The obvious conclusion is that there is something different about the way the Lemon transmitter modules work with these DSM2 receivers, and the way they work is not normal.

Quoting from a Spektrum AR9100 Manual: "When power is restored, the receivers will immediately attempt to reconnect to the last two frequencies they were connected to. If the two frequencies are present (the transmitter was left on) the system reconnects typically about 4ms. The receivers will then blink indicating a brownout has occurred."

Each time the Lemon transmitter modules are turned on, they are always choosing the exact same two frequencies for DSM2. They should be choosing different frequencies each time they are powered up. Choosing different frequencies each time the transmitter is turned on is how the DSM2 receiver knows the difference between a brownout and a normal startup. The Lemon transmitter modules are never changing the two DSM2 frequencies, and that is what is causing the blinking brownout light to trigger when the receiver is turned on.

So what I'm asking over here on Mode Zero is if anybody has one of the Lemon transmitter modules that was purchased and shipped after March 5, 2021, can you please check to see if it always powers up using the same two DSM2 frequencies. If it does, then each time the DSM2 receiver is powered up the brownout light will immediately begin blinking, even if the transmitter power was cycled before the receiver was turned back on. This will happen if the receiver and transmitter have been powered off for minutes, hours, or days. It is not a matter of quickly cycling the transmitter or receiver power.
Built a Heathkit GD-19 in 1969. Been flying RC ever since!
bluejets
Posts: 179
Joined: 19 Jun 2019, 04:09

Re: New Lemon transmitter module, DIY & JR formats

Post by bluejets »

If it's that much bother, I'd tend to chuck it in the nearest rubbish bin and cut your losses.
Dave McDDD
Posts: 18
Joined: 28 Apr 2020, 19:37

Re: New Lemon transmitter module, DIY & JR formats

Post by Dave McDDD »

I was simply hoping to find someone else here on Mode Zero who has a production version of the Lemon transmitter modules, and who has experienced the same blinking brownout light problem with a DSM2 receiver. This forum has some electronics gurus whose opinions I value, which is why I posted the problem here in the first place. Hopefully they will eventually find this thread and respond.
Built a Heathkit GD-19 in 1969. Been flying RC ever since!
Martin
Posts: 554
Joined: 16 Feb 2018, 14:11
Location: Warwickshire

Re: New Lemon transmitter module, DIY & JR formats

Post by Martin »

I think Mike_K's post on the previous page answered this issue - it's a "feature"of the LemonRX module, not a "fault". The feature will generally lead to improved DSM2 performance, but unfortunately also makes the receiver brownout detection less useful.

Most DSM2 transmitters pick two random (but currently unused) frequencies from the 2.4GHz band each time they're switched on.

The Lemon transmitter module, when it's powered on, remembers the same two frequencies it used previously - and it uses those unless they're in use by another transmitter, in which case it does then pick one or two new random frequencies to use.

This will provide better performance than standard in the event of transmitter power glitches (or the user accidentally switching the transmitter off and back on). An unfortunate side-effect is that it (usually) causes the receiver brownout LED to flash.

I think if you need a DSM2 receiver brownout LED to work exactly like it would with a Spektrum transmitter, then you'd best avoid using the Lemon module (unless and until Lemon provide a firmware update).

I'm quite happy to continue using mine - I think the benefits outweigh any slight disadvantage. And of course, with a DSMX receiver, it's not an issue at all.
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stuart mackay
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Location: Swaffham, Norfolk
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Re: New Lemon transmitter module, DIY & JR formats

Post by stuart mackay »

I forwarded the question to the Tech guys at Lemon and here is their initial response:

"If the last known receiver is DSM2, the DIY or Plug and Go module will search for 2 most quiet channel during power on before transmission.

The search is sequential, and it is quite often that the 2 most initial channels are quiet so it remains to reuse the same channels.

Although this wont be a problem with safety for flying, we will soon look into the issue ASAP."
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Mike_K
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Joined: 16 Feb 2018, 06:35
Location: Hertfordshire

Re: New Lemon transmitter module, DIY & JR formats

Post by Mike_K »

Thanks Martin for better describing what I was trying to say, it is a deliberate safety feature that improves on other DSM2 transmitters, but does have a minor side effect of flashing the receivers brown-out/lost packets LED.

Stuart, thanks for getting confirmation from LemonRx that this is a design feature. But I do hope Lemon Rx leave their modules as they are, this feature has safety benefits ie quicker re-bind when using DSM2 than other DSM2 transmitters. My Rx are usually so buried away in the fuselage that I can't see the LED anyway.

I've been testing my new encoders using a Lemon Rx DIY module and have logged over 100 flights in the past week (the advantage of living on an old farm with your own flying field!) without a single issue and around half those flights have been with DSM2 receivers. And I've also used a wide range of Spektrum, JR, LemonRx and OrangeRx receivers from small indoor Vapors to 10 channel PowerSafe without a single issue.

They have so many benefits over the OrangeRx modules I don't know where to begin. They are cheaper and readily available, they are smaller so more easily packaged, have FCC approval for use in the USA (the FCC have specifically stated that OrangeRx / Hobby King modules are illegal to use in the USA when they handed HK their massive fine), you actually get a personal answer to technical queries, they listen and respond to their customers, there is none of the pressing the button on an OrangeRx module to select DSM2/DSMX/11mS/22mS with 0/1/2/3 flashes and in this instance have added an extra safety feature. In fact, I think they have improved on genuine Spektrum DSM2 modules (like the old DM8/DM9) for use with DSM2 receivers as well. Well done LemonRx.

Mike
stormer254
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Joined: 03 Mar 2018, 10:08

Re: New Lemon transmitter module, DIY & JR formats

Post by stormer254 »

Yes I also have this 'problem/ issue' with my Lemon plug in module, al the rxs I use at the moment are Orange DSM2, and I have flown many flights with the led flashing with absolutely no problem at all. The previous Orange modules I had were/ are extremely unreliable to the extent I would rebind before every flight My problems with the Orange modules is documented in other threads on here, despite some good advice I never had a positive answer, one interesting fault when turning on would be a solid bind light but no functions working or functions moving to different controls, when added to a slightly suspect range issue, I had to walk towards the aircraft holding the TX above my head several times.......... The only positive reply I got was to reflash the firmware, no idea how to do that, I was a builder in real life! So I will live with this Lemon foible!
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stuart mackay
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Re: New Lemon transmitter module, DIY & JR formats

Post by stuart mackay »

Gents, the word problem/issue is being used here and sadly, it looks like an "urban myth" is being created when, actually, what you have seen is a deliberate design and safety feature incorporated in the LemonRx module.
I have already had some questions from potential users, saying that they have heard that on "mode-zero" that an issue has been discovered, which clearly is not the case and might be that the "armchair experts" either are not reading the entire thread of being selective with the truth before talking to others.
LemonRx are a small business, who want to support us all, let's not bite the hand that feeds? :lol: :lol:
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