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Lemon diy (hack) module


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Hi Guys

This might be of interest to anyone owning old (legacy) transmitters on 35Mhz.

I have four of the old style JR transmitters, 2 x 2610 and 2 x 2720. One of each I have converted to 2.4 using FrSky DHT hack modules. Looking to probably convert the other two at some stage, but the DHT modules are pretty hard to find and given FrSky changing protocols every five minutes, the V series and D series receivers are probably on their way out too.

Seems now that Lemon have stepped up and produced a hack module, which uses their DSMP protocol, which means DSMX and DSM2 from Spektrum, plus Lemon's own range.

Details here

Already found out that Radiomaster receivers will bind to my DHT modules, so that's my receiver needs sorted for a good long time.

Jeff

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DHT has been discontinued so you will not be buying a new one. 

I have just bought he Lemonrx Tx hackmodule and a six channel rx.

The module is destined for a MC24 along with a V8HT FrSky hack mudule I managed to source. This will mean I can use a great Tx with a the large number of 2.4 Ghz rxs I seem to have accumulated.

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Hi Kim

Seen that module on the T9 site, but i didn't notice it binds to D8 receivers as well. (note to self, read the small print).

Yet to find a UK stockist for the Lemon module, but they will supply direct from the factory.

Priced at $28.30, which is somewhere between £17 and £20 depending on which conversion site you use. Buying direct means shipping costs as well, but either way much cheaper than the FrSky one.

However, now that Radiomaster are producing receivers which will bind to D8 much cheaper than the Frsky ones that has to be in the balance as well.

Decisions, decisions

Jeff

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If you want Lemonrx stuff from a reliable UK source search:

eBay   Toys & Games   RC Model Vehicles & Remote-Controlled Toys   Lemonrx

and make sure you are buying from 'planesamtheman'.

You will be buying from Stuart Mackay of Stuart Mackay Models.

He is also very involved, along with others, in the Mode Zero forum which caters for all sorts of vintage radio control and modelling enthusiasts.

It is a treasure trove of useful and interesting stuff.

I have no connection to Stuart Mackay Models other than that of satisfied customer.

 

 

Edited by Wookman
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Hi Guys

Christopher

How do I find Root729 on e-bay? Never found a way to search for a seller.

Also, reminder that Align-Trex stock the full range of Lemon receivers. Just done a quick comparison of a standard 6 ch DSMX rx.

Mackay Models    £17.50

Trex                       £17.48

There, saved you 2p already, public service at its best.

Jeff

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Jeff.

Searching for a particular trader on eBay has come up before as follows. I've just tried it with "Root729" and it works. Nothing for "planesamtheman" though - maybe not registered as a shop?

 

On 13/04/2021 at 13:31, Gary Manuel said:

Not sure how to do it on mobile phone because the option isn't there, but on desktop, if you click on the word "advanced" at the side of the search button, it brings this up - select Find Shops.

 

image.png.260a18d2682a6dcec499e2140f529fce.png

 

Then enter search string.

 

image.png.b470f8a399b5b4c484fc3e11ffccc225.png

 

Results appear. This particular one also partly helps with my first question as it cross references to the proper site.

 

image.thumb.png.8d2d8efa29ebca440321d5ee9e1abc1b.png

 

 

Edited by Gary Manuel
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Hi Gary

Thanks for that, worked a treat.

If you want to find 'planestheman' put LemonRX in the search box and the first entry that come up is from him.

Otherwise put 133739499790 into the search engine, then go to 'other items' to see the range.

Did notice that he has the hack module in stock, but priced at £28.50, where direct from Lemon is $28.30.

Significant difference.

Jeff

 
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Hi Gary

Not sure if that's right.

Official Gov website says anything below £135 is not subject to import tax, and anything below £39 and not a 'gift', VAT will be paid by the seller.

In theory there should be nothing more to pay, but I say 'in theory' because gov are not too good a keeping their sites up to date, and things might have changed.

We'll see

Jeff

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Hi Guys

Ordered the Lemon module direct from the factory. Total cost inc shipping came out to £26.47.  Assuming I don't get caught for import duty, that's cheaper than buying off e-bay, though not by much.

Really depends if you want it quicker. We'll see.

Meanwhile, one question.

In the instructions it mentions that the module is not EU compliant in that it can transmit in DSM2.

Given that Lemon are still selling DSM2 receivers over here, what kind of a risk would I run using these?

Not going to get the Home Office gestapo demanding my first born as a penalty, am I?

Other than that, seems pretty straightforward.

Cheers

Jeff

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Hi Jeff

 

I wouldn't worry too much about using the LemonRx modules with DSM2, but if you're worried with the low cost of LemonRx DSMP receivers, just buy a few.

 

The legality of using a LemonRx module with a DSM2 receiver is no different to using an OrangeRx DSM2/DSMX module with a DSM2 receiver is a grey area and I've previously checked with the BMFA that it wouldn't invalidate my BMFA insurance, which it wouldn't. And I don't think you need worry about OFCOM. DSM2 is obviously a very old protocol and there are better protocols now in use (all the FHSS protocols are technically superior), but many of us still happily fly on 35MHz where there is only one frequency channel with no redundancy whereas DSM2 uses 2 bands that are both spread spectrum, so it's still fairly resilient and in the real world I've had 1000s of interference free flights with DSM2, as have 1000s of others. Most who have had problems could probably trace them to poor installation, a poor battery/inadequate ESC BEC or cheap fake Spektrum receivers bought on eBay or similar. Which is why I prefer using a LemonRx receiver over a Spektrum labelled receiver, at least with a LemonRx you know you're getting a genuine receiver, but unless you buy your Spektrum receiver from your LMS, you never know if it's genuine or a fake. Finally I'd imagine that LemonRx will launch a CE compliant module, they've launched the modules with FCC certification, as the USA is their largest market, but traditionally they do listen to customers and making them CE compliant just requires them to disable DSM2, the FCC test house have already done all the other relevant tests needed for CE while doing the FCC certification. If you an techno-junkie like me, you can read the LemonRx FCC test report (or Spektrum, Futaba, FrSky, JETI etc) on the FCC website:

 

https://fcc.report/FCC-ID/2ATBKDSMPSDR

 

Cheers

 

Mike

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Hi Mike

Thanks for that succint and cogent explanation. No worries on that score.
The flying field I use is in the middle of a farm, well away from civilisation, and most times it's only me there. I still fly 35Mhz on occasion, so that comparison is also valid.
Only question I had was as to possible illegalities, and you've put my mind at rest on that aspect.
Another question, if I may. Nothing to do with legality or otherwise, more a curiosity.
I currently have FrSky and FlySky receivers in use, and both are equipped with two aerials and current suggestion is they be placed at right angles to each other for best coverage.
Not going to put the Lemon gear to use straight away, so looking for a cheap receiver from their range just for testing purposes.
Considering either the LM0019N or LM0021S.
The 0019 appears to have only one aerial, leading back from the board, and the 0021 has two, but straight out from either side of the board in line with each other.
Can't imagine this to be a problem, but counter intuitive to what I understand (not much) about 2.4.
Your thoughts?
Jeff

 

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On 02/07/2021 at 10:06, Jeffrey Cottrell 2 said:

The 0019 appears to have only one aerial, leading back from the board, and the 0021 has two, but straight out from either side of the board in line with each other.

Jeff, on the six channel receiver, the two aerials can be easily orientated to achieve the 90 degree preferred orientation.

The single aerial Rx is also very good and I have flown one to nearly out of sight range, but clearly does not have the signal security that the diversity receiver offers.

 

The twin aerial is as good as, if not better than any other diversity receiver, and for £17.45 proving very popular compared to what you will pay for a comparative Spektrum Rx.

 

Our experience with the LemonRx low power ground range tests is usually  around 90-100 paces, a bit more than the 30 or so that is found with some systems.

 

Also with the DIY and Plug and Go modules that we sell from the UK, we do a no-cost firmware update to disable DSM2 if the customer prefers, also we have large stocks here, so next day delivery, no additional VAT/Duty on personal importation, discounts for multiple orders and local back up is part of our service we offer our UK/European customers .

 

Futaba Tx bay pinout.jpg

FUT-HITEC_tx_pinout.jpg

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Picture1.jpg

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Edited by Stuart Mackay 1
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Hi Stuart

Many thanks for the extra information, and the video you posted. Very helpful.
Most impressed by the size (or lack of) of the Lemon module. Shouldn't have any trouble finding a corner to hide that away.
Had a re-think about the receiver. I originally chose the DSM2 one because it was cheap and only to test if the system was working.
Logic took over (channeling my inner Spock) and seemed that if it was working I would want to put it to use.
So, got a 6 ch DSMX one coming. After all only about £5 more, and seemed an easy way to avoid potential DSM2 issues by using DSMX from the start.
Meanwhile apologies to you.
I ordered these direct from the factory, before I knew you stocked the range over here. Rest assured, when I need more, I'll be talking to you.


Changing the subject slightly, another question for the radio experts out there.


When I converted my transmitters using the DHT module, I was using exclusively V8 receivers in 7 and 8 ch form. The DHT module has a switch to change from V8 (non-telemetry) to D8 (telemetry).
Couldn't see any reason for having this switch, so I did away with it and set the module to permanent one-way by shorting two of the pins.
Your mention of 90 paces range test on the Lemon module reminded me that I got similar range with Radiomaster receivers on the DHT module.
Here's the oddity.
The RM receivers bind in D8 mode, so I undid the short, effectively setting the module in D8 mode. This form the RM receiver bound up fine, and did a good range check.
However, it seems the receivers I bound in V8 mode still bind up fine as well. So, once bound in one mode, would you expect them still to work with the module in the other mode?

Puzzled by that, any thoughts?

Jeff

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Hi guys

My Lemon module and receiver arrived today. They were ordered on the 2nd so that's only 10 days from Far East. That includes two weekends so pretty pleased with that.

Andy

I recall sometimes when binding my V series receivers that I had to use both methods, the shorting key and pressing the bind button on power up. Just thought it was an odd quirk of the system, and gave it no further thought.

Having said that, I have it on good authority that the pins I shorted would lock it in one-way mode. Ho hum. As far as I'm concerned, if it works I'm happy. If the weather ever clears I'll go down the field with one of the models and give it a proper range test.

Meanwhile, a question. First of many probably.

On the 2610 I converted some time ago there were three wires from the encoder the the rf board. These I used to connect the FlySky board.

I am going to use the same leads to connect the Lemon module. These wires are one red and two white. Red is obviously signal, but I put a meter on the other two to sort out pos/neg. Easy to work out, same wires as a servo plug, but in the course of doing this I measured the supply voltage as only .73v. Is this enough to power the module?

Manual says transmitter power from 4.8 to 12v, but not sure if I should be seeing this at the module supply in.

Your thoughts?

Jeff

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Hi Guys

Lemon set up got its first outing today. On the basis of one flight, performed perfectly. Can't really say much more, apart from 'it does what it says on the tin'.

Install was a doddle apart from one minor mishap. Thanks to Stuart Mackay for sorting that out.

Long term, time will tell, but very pleased so far.

Cheers

Jeff

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  • 1 month later...

Just successfully fitted Lemon DIY module to my 35mMhz Futaba T6EXAP transmitter. Idea was to bind to a DMS2/DSMX Rx which came with a Chinese foamy kit, and get into the Spectrum protocol. Module bound OK,  BUT - the throttle channel and aileron channels obviously need re-asigning. Is there a reasonably simple way to do this? Anyone??

 

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