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Jan 19, 2002, 04:32 AM
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DIY Infra-red ?

Has anyone seen any circuits for building infra-red transmitters and receivers ? Last time I asked this question on Modeling Science several people told me it was really easy to do but no-one came up with any circuits or even detailed descriptions of how they work. E.g. do they use a carrier (what freqency 38KHz ?), is the encoder output simply "amplitude modulated" i.e. switched onto the carrier etc.

I like playing with electronics so I'm pretty sure I could design myself a system that would work but I'd prefer it to be compatible with existing receivers etc.

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Jan 19, 2002, 05:16 AM


I have never seen a circuit diagram, maybe because you have to program the pic chip anyway. I can supply you will the parts for the Z Tron system and you could make it from a kit if you like.
If you design your own you are reinventing the wheel, which is ok if thats your interest, but micro flight has lots of other problems sort out.
Also we are back to the problem of finding the parts in small quantities ...
Jan 19, 2002, 05:43 AM
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jberg's Avatar



Originally posted by aeronutz
Also we are back to the problem of finding the parts in small quantities ...
Mark [/B]
try , they have almost everything you can imagine, starting from very low quantities. Not cheap, but at least you get what you need.
Jan 19, 2002, 02:22 PM
i'd suggest looking at the surplus places as well, like american science and surplus, and electronics goldmine.

if you know what parts you are looking for, maybe we can help you find them.
Jan 19, 2002, 09:20 PM
Sticky Shepherd
Graham Stabler's Avatar
As you Marks says if you can program a pic you can make the tx. It does use modulation but I can't remember the frequency. Also the ztron doesn't use quite the same pulse train as a std tx. So if you wanted it to work with ztron receivers you would have to find out the exact pulse format.

If you want to do it all yourself you could re-jig an rf tx just replacing the radio transmitter part with an oscillator to produce the correct modulation frequency for your ir receivers. This could then drive a mosfet switching an arrray of ir leds. This is a pretty cheap wat to do it but I think you would have to do your own rx as well and that involves some tricky pic programming.

People like digikey, farnell etc do have everything you can imagine but not necessarily the thing that you want. I have been looking for filters and other bits fro an rf receiver I'm working on and you just can't buy the ones I want. Even the samples I requested had to be specially made in japan. If I could afford a gram more on the design there would be no problems.

Jan 19, 2002, 11:33 PM
Grand Poobah of Nothing
Trizza's Avatar
I'm working on one right now. Post about it a page or so back on this forum. When its done I intend to release the software and the hardware (including the MCU programmer) design on my website.
It utilizes 2 AVR micro chips that retail about US$3 and an old computer joystick. Still in a very early stage so don't expect too much about it for a while. Still debugging and fine-tuning the code for a single channel, before I expand it to the planned 3 channels with channel reverse, electronic trim, and v-tail mixing.
Jan 20, 2002, 04:51 AM
Thread OP
Cheers Mark/Graham, I guess I'll just have to give up and buy some stuff. I tried that a while ago but it was impossible to get the transmitters from anywhere. That's the main reason I built a simple one of my own (using it with electric control line now cus the receiver is HEAVY !). Apparently FMA were going to sell the transmitters and then they weren't and Mr Z-tron wasn't answering any emails. Are they available again ?

Thanks Trizza, single channel would be fine for my electric C/L stuff which is also not so weight sensitive but you're right more channels are needed for micro r/c (remote control not radio).

But why AVRs ? I've only just about got to grips with PICs. I really don't want to have to learn my way round yet another microcontroller .

Jan 20, 2002, 06:31 AM

Good news

Steve - I have a spare Mk 3 Tx here if you are going to fly indoor one and two cells planes with it. If you want to fly control line then Z Tron have just made/are making a special Tx for that purpose, because you obviously dont need a standard Tx for three channels.
I have some Rx kits and coils too, let me know what sort of plane you want to fly and what size hall you have and I will advise on model size if you like.
I will post a new thread with regards to our latest two cells planes ....

ps Sergio told me he had 500 of the Mk 3 transmitter boxes and sold them all - so it migth be possibll to get one second hand and they where available for a couple of years but seemed interested then. We are still looking for a new supply of CHEAP Tx boxes that will be suitable.
Last edited by aeronutz; Jan 20, 2002 at 06:33 AM.
Jan 21, 2002, 01:00 AM
Grand Poobah of Nothing
Trizza's Avatar
AVRs are much better value for money - here the 18 pin pics are upwards of AU$15 each, whereas the 20-pin AVRs are AU$5 each. They have more memory, higher clock speeds, better instruction set (allowing even more program to be packed in), the IO pins are configurable either way, instead of some in some out like PICs seem to have, and besides, a very very easy programmer can be built for a couple of dollars. I'm a very price-minded person so I opted for the cheapest solution to getting into MCUs, and AVRs seemed to be just that.

Heck, for the price of an 18-pin PIC I can get the top of the range AVR without going into ATMEGA chips, the AT90S8535 (40 pins, a heap of ADC pins, 2 external interrupts, analog comparators, the lot).
I urge everyone to check em out, they're great.
Dec 19, 2002, 12:51 AM
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Koichi Tanaka's Avatar
I am making and testing the infrared transmitter and the infrared receiver.
Transmitter Futaba'challenger' was converted.
A receiver is only 1.3g.
A DC/DC converter, a speed controller, and magnet actuator driver are contained in the receiver.
There are 130 feet or more of distance of operation.
PIC12C509A is used for the transmitter.
The charge pump DC/DC converter is used for the receiver with PIC12C509A and IRF7805 FET at it.
The test flight was successful in the gymnasium.
Last edited by Koichi Tanaka; Dec 19, 2002 at 02:51 AM.
Dec 20, 2002, 08:54 PM
Registered User
Koichi Tanaka's Avatar
The new infrared transmitting module was made.
It will test in a gymnasium tomorrow.
It uses setting to the trainer terminal of a transmitter.

Dec 21, 2002, 01:21 AM
cool project. Put some of those buddy boxes to use.
Dec 22, 2002, 07:58 PM
Registered User
Koichi Tanaka's Avatar
It flew in the gymnasium yesterday.

It flew satisfactory at all.

The weight of an airplane is 12.9g.

The airplane which set the infrared receiver, and the transmitter which set the infrared unit.
Dec 22, 2002, 09:02 PM
in pursuit of low wing loading
Gordon Johnson's Avatar
Very nice work on a IR that works off the buddy box plug in a standard TX. I think this is the way to go.

Could you give some more details on your plane? It looks like it is rudder and throttle. What was your wing area, what motor/gear/prop did you use. Anyway, very impressive.

Dec 22, 2002, 11:05 PM
Registered User
Koichi Tanaka's Avatar
It used the motor from DigiQ, having removed.
The weight of a motor is 0.7g.

The 1mm ball bearing is used for the driveshaft.
A gear is 81t and 9t of DiDel.
With the balsa propeller of 127mmx64mm, it is is thrust which both exceeds 10g by 140 mAh Li-Poly.
A motor unit is fixed with a magnet.

Wingarea 4.47dm2, Wingspan 473mm, Length 495mm, Wingloading 2.9g/dm2.

Airframe 4.6g + Propulsion-unit 1.7g + prop 0.3g + IR combo receiver 1.5g + Magnet actuator 0.6g + 140mAh Li-Poly 4g + Other 0.2g = Total 12.9g.

Last edited by Koichi Tanaka; Nov 04, 2005 at 08:41 PM.

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