Introducing...the DIY IR and RF transciever and reciever Wiki!

cheesehead

Lifer
Aug 11, 2000
10,079
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Link to the WIKI!

For the past decade, people have been bodging together tiny radio and IR recievers for use in R/C airplanes. However, with the exception of a few commercial designs, work has been in so many branches that no real progress has been made. Of the few working designs, documentation ranges from lousy to nonexistent. And, from what I can tell, the same questions get asked and answered again and again and again.

In an attempt to fix that, a fellow RCgroups member by the name of Cpt. Frazz has started a Wiki on DIY reciever design. This is useful for many areas; replace the H-bridges used for the electromagnetic actuators (Yes, we use coil-and-turning-magnet actuators) with bigger H-bridges, and you have a perfect platform for a wireless micro-tank. Add a camera to the the data input on a Nordic 2401A tranciever, and you've got a UAV electronics module with onboard microcontroller in addition to remote-control functionality. And so on.

If you're familar with wireless data transfer, SMD electrical design, microprocessor programming, RF engineering, or anything else remotely related, please post and give us a hand. At this point, we're starting from the ground up; feel free to fill in everything from basic radio formulas to FCC regulations.


Thanks,
Spasticteapot, A.K.A Cheesehead from the RCgroups forums.
 

bobsmith1492

Diamond Member
Feb 21, 2004
3,875
3
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I've worked with surface-mount parts and reflow soldering as well as programmed a few microcontrollers if there's anything in particular or general you'd like me to add.
 

cheesehead

Lifer
Aug 11, 2000
10,079
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If you could post some details on producing PWM outputs on the PIC and AVR, and perhaps some information on reading potentiometers, that would be great.

EDIT:
If you can find Koichi Tanaka's PIC code for his IR remote-control reciever, it's a good starting point. If you could document what part of the code does what, it would make life easier for everyone.
Also, if you could figure out how to make it recieve data over a RF link instead of an IR detector, you would be worshipped as a hero..providing it's light enough.
 

f95toli

Golden Member
Nov 21, 2002
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Isn't the problem with "DIY RF" that it is illegal in most countries?
I know there are some "free" frequency bands but AFAIK if you biuld your own transmitter you still need to have the equipment tested and approved to make sure that you are not radiating at some other frequency (at least if it a reasonable powerfull transmitter) .
And yes, these laws ARE enforced.

edit: I looked at the wiki-page again and I guess the chip from Nordic Semiconductor is OK since it works at 2.4 GHz.

 

cheesehead

Lifer
Aug 11, 2000
10,079
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Originally posted by: f95toli
Isn't the problem with "DIY RF" that it is illegal in most countries?
I know there are some "free" frequency bands but AFAIK if you biuld your own transmitter you still need to have the equipment tested and approved to make sure that you are not radiating at some other frequency (at least if it a reasonable powerfull transmitter) .
And yes, these laws ARE enforced.

edit: I looked at the wiki-page again and I guess the chip from Nordic Semiconductor is OK since it works at 2.4 GHz.


Actually, the 27mhz (toy) and 2.4 ghz bands are pretty much free, and the 72mhz band is more or less uninforced. The 433mhz band and 900mhz band are also accessible, IIRC.

Also, the IR spectrum is ENTIRELY uninforced. (Seeing as how it can be blocked with a piece of paper.)

EDIT:
Due to dumb luck, I'm essentially a "Wiki Moderator".

I have no idea what I'm doing.

If there's anything you want to see added, re-arranged, fixed, or done, let me know.

Also, if you can do SMD work cheaply or in trade for random goodies, I'd appreciate it. Most of this stuff is too bloody tiny for me.
 

f95toli

Golden Member
Nov 21, 2002
1,547
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Yes, but my point was that if you make your own transmitter for the 2.4 GHz band you have to be sure that you are really only transmitting in that band. The problem is that most "simple" transmitters tend to send out signals at various sidebands as well which, again, is illegal. You have to be VERY carefull when designing RF equipment.

IR is of course free but then you are limited to line-of-sight applications.


 

cheesehead

Lifer
Aug 11, 2000
10,079
0
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Originally posted by: f95toli
Yes, but my point was that if you make your own transmitter for the 2.4 GHz band you have to be sure that you are really only transmitting in that band. The problem is that most "simple" transmitters tend to send out signals at various sidebands as well which, again, is illegal. You have to be VERY carefull when designing RF equipment.

IR is of course free but then you are limited to line-of-sight applications.

We're using Nordic Semiconductor modules, so that's not a problem. Everything's built on-chip.