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        Help! DIY Infra-red ?

#1 steve lewin Jan 19, 2002 03:32 AM

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.

Steve

#2 aeronutz Jan 19, 2002 04:16 AM

DIY IR
 
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 ...
Mark

#3 jberg Jan 19, 2002 04:43 AM

Re: DIY IR
 
Mark,

Quote:

Originally posted by aeronutz
Also we are back to the problem of finding the parts in small quantities ...
Mark [/B]
try www.digikey.com , they have almost everything you can imagine, starting from very low quantities. Not cheap, but at least you get what you need.

#4 Mighty Mik Jan 19, 2002 01:22 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.

#5 Graham Stabler Jan 19, 2002 08:20 PM

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.

Graham

#6 Trizza Jan 19, 2002 10:33 PM

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.

#7 steve lewin Jan 20, 2002 03:51 AM

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 :(.

Steve

#8 aeronutz Jan 20, 2002 05:31 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 ....
Mark

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.

#9 Trizza Jan 21, 2002 12:00 AM

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.

#10 Koichi Tanaka Dec 18, 2002 11:51 PM

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.

http://www.cityfujisawa.ne.jp/~toko/pic

#11 Koichi Tanaka Dec 20, 2002 07:54 PM

The new infrared transmitting module was made.
It will test in a gymnasium tomorrow.
It uses setting to the trainer terminal of a transmitter.

http://www.oyajin.gr.jp/~toko/image/ir-unit07.jpg

#12 Mighty Mik Dec 21, 2002 12:21 AM

cool project. Put some of those buddy boxes to use.

#13 Koichi Tanaka Dec 22, 2002 06:58 PM

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.
http://www.oyajin.gr.jp/~toko/image/02122201.jpg

#14 Gordon Johnson Dec 22, 2002 08:02 PM

Koichi,
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.

Gordon

#15 Koichi Tanaka Dec 22, 2002 10:05 PM

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 handmade.here 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.

http://www.oyajin.jp/~toko/image/17-unit.jpg


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