DIY IR LRFers - RC Groups
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Aug 01, 2003, 07:09 AM
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I started this model last night. Obviously inspired by the Midge and a want for something a bit more relaxing than the helis to fly in the living room.
Expecting it to be a bit heavier I increased the wing area by approx 50% to 72sq in. Span is 8 inchs. Airframe without wheels is 2g. Guesstimates say: model 2g, batt 2g, IR 2g, motor/g/p 2g. All up weight less than 9 grams. When I get some more CF I'll make a carbon version.

Updated 3/3/05

Planning to use Koichi Tanaka's DIY infra red, discussed here and in DIY infra red thread. This is a 3ch unit, rudder, elevator and throttle. Receiver has inbuilt ESC. Transmitter consists of small module that plugs into trainer jack or if you don't have this feature it can be wired into most transmitters. A stand alone tx can also be made using playstation controller and joysticks.

Thanks and credit to Andy Birkett.
Credit and many thanks to Koichi Tanaka for his help.


MicroWorks For small model supplies in Australia

Koichi Tanaka's web page

IR Tx module schematic and hex file No's 15 and 18. Koichi's page PIC/AVR learning.
IR Rx schematic and hex file No 16. as above (for 200 ohm coils)
PIC writer, as above
Flat package adapter No 1, as above
Flat package adapter pictures, page 20 and 31 DIY infra red

Babelfish translater

Because transmitter channel assignment and neutral differs between brands, it is neccessary to use receiver software to suit your particular transmitter.
Transmitter software is same for all three transmitters, is both 38 and 57kHz and selectable by switch.
Transmitter schematics differ between brands because of different trainer jack socket and shift. My Hitec Eclipse works with Futaba schemtic with throttle trim all the way down.
Receiver software (hex files) is available to suit Futaba, JR and Sanwa transmitters.
Receiver can be made to operate on 38 or 57kHz, simply by using 38 or 57kHz sensor.

Koichi now has a number of IR transmitter and receiver units to choose from. Details of all can be found on his PIC/AVR page.

JDM programmer


IR receiver component layout
Parts List Has links to Digikey, Linear Technologies and Maxim. Credit and thanks to Dindea
Rx pcb layout for Max1595
Lightening Sensor
Thinning pcb
Picture of finished Rx
Formula Wheel
200 ohm Coil Specs
Picture of Flat Package Adapter smd pic to dip socket
Flat Package Adapter Another way of doing it.
UV Lamps
Rx pcb layout for LTC3200
Mechanical timer has 12/60 M3 gears and coil wire
Component Size Chart Courtesy of clipclop
Koichi's pcb artwork for 200ohm Rx

Programming hints and tips.

Keep progammer lead short, better still, plug programmer directly into PC.
Download hex files directly from Koichi's site, don't download whilst viewing through babelfish.
If you are having problems go to ICprog "settings" and click on "clear settings" and check that your settings are correct. My hardware settings (98SE) are:
Ports = Com2
I/O delay = (4)
Interface = Windows API
Communication = all unchecked
Last edited by david_dewit; Mar 03, 2005 at 03:22 AM.
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Aug 01, 2003, 07:14 AM
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Last edited by david_dewit; Aug 04, 2003 at 08:17 PM.
Aug 02, 2003, 07:54 PM
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bmutlugil's Avatar
Hi David,

That looks very good. Were the TX and RX schematics published in the DIY IR thread?

I could convert my long forgotten 27MHz TX to IR - this band is dangerous to use here.. I have some experience with IR coding (RC5). I had built a uP RX working with standard IR TV remote control units - this was for a mechanical engineering student project - it was only multi channel on-off control. People kept asking if the robot (a mars rover kind of thing) received all TV channels, during the project contest

I don't have the time for anything news, though.

Best regards,

Aug 03, 2003, 07:20 PM
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Hi Bulent,

for schematics and hex files see index above

Last edited by david_dewit; Oct 21, 2003 at 12:05 PM.
Aug 04, 2003, 08:19 PM
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Aug 05, 2003, 12:05 PM
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isaac-bees's Avatar
wow! Both the RX and the tx are really simple! (looking at least) What kind of signal do the tx units require? I have a ACE micropro8000 with dual freq. but I am not sure what the output going to the rf board looks like. Would a gws tx work?
Aug 06, 2003, 06:53 PM
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I guess most transmitters will work, my IR Tx module plugs into trainer jack, makes it easy.

Source for small gears and some other goodies is 24 hour mechanical timers. Gears are 60/12 x .2
Aug 07, 2003, 07:12 AM
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The timers are selling for $5.95 AUD.
One Didel 60/12 is approx. $5.10 USD.
There are three 6o/12 x .3 gears in a timer, enough for one two stage gearbox, ($38 USD)
The enemaled wire might be suitable for some actuator coils.
25:1 gearbox.

Last edited by david_dewit; Aug 16, 2003 at 05:19 AM.
Aug 15, 2003, 06:26 AM
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First go at pcb.
Have soldered sm pic in place and done programming.
Don't realise how small it is till you get this far.

Aug 15, 2003, 06:47 AM
Thats NOT indestructible
j8m8l's Avatar

That is really tiny !, nice work.
Did you design the board?

Aug 15, 2003, 08:08 AM
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Hi Josh,

The board is similar, but not identical to Koichi's board.
Measures 14 x 11 mm.

Aug 15, 2003, 09:02 AM
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Rough drawing of pcb layout, on grid paper, good for quick scale drawings.

Aug 15, 2003, 09:13 AM
Thats NOT indestructible
j8m8l's Avatar
I see it now, very nice.
That includes v boosting doesnt it?

Aug 15, 2003, 09:28 AM
Registered User
Thats right Josh,

LTC3200ES6-5, 100mA low noise charge pump.
IRLML2502 mosfet, N SOT-23
0805 104 cap, .1uF x 2
0805 105 cap, 1uF x 3

Last edited by david_dewit; Mar 02, 2004 at 06:33 PM.
Aug 15, 2003, 09:42 AM
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Does anyone use a mill to make pcb's? to cut copper away,
instead of using etchant or a knife as I did to make above pcb.
Looking for an easier method.


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