Availability: 33 In Stock
Sku: LMT0002

The Lemon Rx DIY module addresses the need for RC modeler in legacy transmitter conversion. The firmware is specifically designed to restore the original PPM waveform on Lemon Rx or Spektrum receiver. The module accepts 5V to 12V as supply input while accepting PPM signal from 3V to 12V with auto detection on PPM signal polarity. The module accepts high tolerance of PPM signal found in some legacy transmitter while accepting a minimum of 2 channels and up.

RCgroups discussion (Click below link for user manual page with link to RCGroups)

Caution before installation

- Avoid static electric by grounding yourself to metallic surface. Metallic surface working table is recommended (such as on top of a laundry).
- Do not interrupt power provided to the module initially. Doing so may damage the RF front-end. Make sure power wiring harness is connected securely before providing power to the module. 
- Install SMT connector to SMA conversion cable to the module as well as antenna prior to power on. Power on without antenna may possibly damages the device.

Antenna connection and Wiring implementation 1
The SMT U.FL connector closest to the center of module should only be used for RF transmission. The optional 3 header pins can be optionally soldered for Ground, V+ and PPM signal in. All these connections are needed for full operation with the on board button for binding and range check. See below diagram.

Wiring implementation 2
Below diagram uses the module pads for direct soldering to suit installation needs. The 3 header pins on implementation 1 can be ignored by using these connections. External bind push button soldering pad can be found here.

Bind procedure and implementation
Bind button on board can be used or externally wired with 2 pads labeled "PB".

- Turn on the transmitter and by pass all the warning messages (if any)
- Wait until the module turns on with red light on and green light flashing
- Release button
- Observe indication. Green light on means binding is completed. Red light flashing indicates bind fails. Turn off the transmitter and resume the whole binding procedure if bind fails.

Range check
During normal operation (green light on), press and hold the button puts the module in range check mode (red light on). Range check mode passes with valid control of the model from 30 meters away. Release the button to allow full power transmission.

1) This is not a Spektrum DSMX or DSM2 product, nor is it a copy of a Spektrum DSM2 or DSMX product. The Spektrum, DSMX and DSM2 brand is a trademark of Horizon Hobby, Inc.
2) This is not an underground black market fake Spektrum product. Lemon Rx quality is guaranteed.
3) Lemon Rx products are tested to be compatible with Spektrum's DSMX and or DSM2 product (Spketrum, DSMX and DSM2 are the registered trademark of Horizon Hobby, Inc.).

Orders are shipped from Columbus, the capital city of Ohio, USA.

An order placed before 2:00pm Eastern Standard Time will be shipped the same working day.

We ship on Monday-Friday by US postal service (USPS) and UPS, and Saturday morning by USPS if a local post office is open. Any order placed on Saturday morning may or may not be shipped the same day. Orders placed on Sunday and US holidays will be shipped the next working day.


Retail orders above $80 may be eligible for free shipping, including contiguous United States, Alaska, Guam, Hawaii, Puerto Rico, and APO addresses. We will use either USPS or UPS that most packages can be delivered in 3-5 working days, but not guaranteed. However, for packages contain large and heavy items, such as power supply, we may use parcel post service or UPS Surepost that may take up to 7 working days to be delivered.

USPS First Class Mail and Priority Mail, Express Mail, and UPS services can be used for domestic addresses. Tracking number and delivery confirmation will be provided to the customer when they are available. If you have not received a tracking information E-mail, please log into your account and click the "view order" link, then click "Track your order" link to find out the tracking number and ship method.

USPS Priority Mail is typically delivered in 3 working days. But very occasionally a priority mail package may be delayed for several days in the mailing system. If delivery time is extremely critical to your order, we would recommend Priority Mail Express or other couriers.

Domestic First Class Mail is only 1-2 days slower than Priority Mail in delivery. We suggest domestic customers choose First Class Mail for an order under 15 oz to save shipping cost.

Real shipping cost is calculated according to package weight and distance, and can be found in the checkout page after delivery address is specified in the fields.

Any order of $200 and above requires addressee's signature confirmation upon receipt of the package. Please contact us in advance or leave a comment in the message box if you want to waive signature confirmation.

We always check the legality of potential fraudulent orders. This procedure may lead to 1-2 working days delay in shipping in some rare cases.

We do not ship products to shipping forwarding companies. Any order shows this kind of address will be cancelled and refunded without notification.


DHL, DHL Express, US Postal Service (USPS) First Class Mail, Priority Mail, and Express Mail (EMS), and UPS services can be selected for international addresses. Shipping cost is calculated according to package weight and distance, and can be found in the check out process. A package usually takes around 7-10 days to be delivered, or occasionally up to 45 days depending on the processing speed in your country, especially in some countries such as Brazil and Russia.

USPS First Class Mail is a budget shipping method. As soon as a First Class Mail package left USPS Chicago hub there will be no tracking information available. If you need detailed tracking information and timely delivery please do not use this shipping method.

Presently we cannot ship lithium batteries internationally by US Post Service or any other air shipping method. Please select UPS Ground if your order contains LiPo or LiFe battery.

We do not ship products to shipping forwarding companies. Any order shows this kind of address will be cancelled and refunded without notification.

Lemon RX DSMP DIY Module for Legacy Transmitters DSMX DSM2 Compatible

Customer Reviews

Based on 6 reviews
Ian C.
Works just fine !

Put this in a first gen DX-6 parkflyer tx, so I could fly the new UMX DSM2/DMX stuff.
The DSM that the radio had , is useless for anything newer than when it came out.


John R.
A great module for updating or building new transmitters

This module is just what I needed to build a modern 2.4GHz transmitter into a classic controller housing. I ended up keeping the housing, gimbals, and switches, and using a microcontroller (Teensy LC) to read the switches and gimbals and produce a PPM signal, which I routed to the Lemon RX module. It works quite well and was simple to integrate. The only additional part I needed was a simple voltage booster to create the supply voltage for the transmitter from a 3.7V LiPo cell.

Jim D.
Lemon TX module

They work great for using on antique propo transmitters conversions to 2.4

Jerry H.
DIY Module Makes for Easy 2.4GHz Upgrade

I still have the first transmitter that I built from a kit back in 1981 - a 3 channel Ace Digital Commander. It is now on 2.4GHz thanks to the Lemon DIY module. The module is very high quality, FCC certified and easy to integrate into most any transmitter. I also purchased a Lemon LM0034 receiver. Binding the module to that receiver and an old Spektrum AR500 I had was quick and easy. I performed the range test procedure with the DIY module and the LM0034 receiver. At 70 paces it was still going strong so I stopped. This was my first order with BuddyRC and they are awesome.

James M.
Lemon RX DIY Module - JR to Spectrum Xlator Box

I put my Lemon RX DIY Xmtr module to use in a JR-to-Spectrum xlator box (Jim’s Xlator box; borrowed idea from the Jeti bridge). I used a JR 6-channel receiver. JR receivers do not have a PPM output, so I used a PWM to PPM converter (readily available on ebay or Amazon) to supply the PPM signal to the module’s PPM input port. I put this in a Pelican 1010 micro case along with a 900 mAH Life 2-cell battery and switch. There was plenty of real-estate left over.

I initially tested it using my little Blade Inductrix FPV. It flew just fine. I then set it up with my latest toy, a Mobula6. It too flew perfectly. I’ve since made at least 100 flights or more – never a glitch.

I was a little put off that I had to rebind the module when switching between the Inductrix and Mobula6. However, the instructions and specs clearly state that it will be necessary to rebind when using receivers of different classes (taken to mean DSM2, DSMX, 11 mS, 22 mS, as I understand it, and perhaps other parameters too – not sure). As far as I know, both the Inductrix and Mobula6 are DSMX. It may be that they have different frame rates, and maybe another parameter or two enter the equation.

It would be great if Lemon developed a module that stores all the bind parameters on the module (PPM only allows one-way comms.; therefore, when using a PPM radio, this data cannot be stored on the radio proper). Such a module will warrant a new purchase.

For vintage radios, for which this module was developed, it is just perfect. Back then, we all used our radios for any number of models by adjusting the mechanical linkages. So, with a vintage radio like the old Kraft and Proline that I enjoyed so much, there will be no rebind issue at all. I don’t recall there being any shortage of fun flying with those radios.

In summary, this is a great little module, diminutive in size, that will allow you to use your favorite radio with all those BNF models, given an accessible PPM signal.

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