Introduction: $4 DIY TV-B-Gone
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About: Hi! I've loved electronics and electricity for as long as I can remember, and electric projects are something I do in my free time for fun. Everything I've learned about electricity is either from experience o…
A TV-B-Gone is a neat little device that can turn almost any TV on or off. It uses a microcontroller hooked up to IR LEDs to output a library of on/off codes. I wanted one but they retail for $20, and I thought I could make one. Adafruit sells akit, and has the code as well as the schematic on their website.
UPDATE! New version available with full building instructions! https://www.instructables.com/id/350-DIY-TV-B-Gone-Mico/
This is a simple TV-B-Gone made completely out of parts I had lying around. It has no circuit board, and all of the parts are just soldered together. I'll include some brief instructions because some people will want to make one themselves.
I have no external oscillator, but the internal one seems accurate enough and has worked on every TV I have tried. It may vary with extreme temperature conditions, though. I got the internal one to run Ladyada's code unmodified by turning off the fuse for the "divide by eight" clock option.
Materials:
Tools:
Mine has a pretty decent range considering that I used very low power signal LEDs, about 10 meters (33 feet) or so.
If anyone makes this, please send pictures! Comments, questions, and ratings are appreciated!
UPDATE! New version available with full building instructions! https://www.instructables.com/id/350-DIY-TV-B-Gone-Mico/
This is a simple TV-B-Gone made completely out of parts I had lying around. It has no circuit board, and all of the parts are just soldered together. I'll include some brief instructions because some people will want to make one themselves.
I have no external oscillator, but the internal one seems accurate enough and has worked on every TV I have tried. It may vary with extreme temperature conditions, though. I got the internal one to run Ladyada's code unmodified by turning off the fuse for the "divide by eight" clock option.
Materials:
- Attiny85v-10pu
- 8 pin IC socket; not required
- Filter capacitors; not required but I used them
- Small tactile button
- Visible LED and resistor; also not required
- 4 IR LEDS with 2 resistors, you could only use one if you didn't care about range.
- 2 AA battery holder
Tools:
- Soldering iron with solder
- Helping hands (recommended)
- Computer with programming software and an AVR programmer
Mine has a pretty decent range considering that I used very low power signal LEDs, about 10 meters (33 feet) or so.
If anyone makes this, please send pictures! Comments, questions, and ratings are appreciated!
24 Comments
11 years ago on Introduction
Hey I read your little description of yourself and I laughed alittle cause it sounds like some thing I'd say. Hey also nice job on the project. If you mind a suggestion encasing it in an "Altoids" tin would make it look cool and it would also make it less obvious when you pull it out.
11 years ago on Introduction
how meny ohms do the resistors have
Reply 11 years ago on Introduction
It depends on the specs of the LEDs you are using. Try http://ledcalc.com/
12 years ago on Introduction
You omitted the resonator in this version. How?
Reply 12 years ago on Introduction
Mainly I did it to lower the cost. I did this by changing the fuses, bits of memory in the chip that determine how it behaves, to tell it to use its internal resonator. If you look at my micro TV-B-Gone Instructable I explain part of this there.
https://www.instructables.com/id/350-DIY-TV-B-Gone-Mico/
13 years ago on Introduction
Great idea. The only thing I’d change is to use all SMT devices to make it smaller and more robust. I found some new flex pcb SMT adapters at www.protoflex.net. These are flex pcbs with an adhesive backing you just stick on. Too cool!
13 years ago on Introduction
I have this idea of an even cheaper version, it goes like this;
1.Connect an IR Photo-transistor or diode to the microphone input of a computer.
2.Fire off a TV-B-Gone at it while recording the output.
3.Connect an IR LED to a 3,5mm stereo-plug and connect to an MP3-player.
4.Transfer recording to MP3, crank up the volume and play the sample.
5.Instant, multicopyable TV-B-Gone disguised as MP3-player.
Reply 13 years ago on Introduction
That's actually a really good idea. Try it and see if it works! You could also convert the TV-B-Gone signal library to a sound file directly (is there an app for that?). Have any idea if a mini-usb from a cell phone would work to power IR LEDS? Good luck!
Reply 13 years ago on Introduction
Also see this on how to make a "40 kHz IR carrier using 20 kHz audio".
Reply 13 years ago on Introduction
Will this really work? The IR signal is modulated at 38-40kHz. Are you sure that both the input and output audio stages can handle such high frequencies? Audio generally stops at around 20kHz and there may be filter networks to dump any frequencies higher than this.
Reply 13 years ago on Introduction
it'll work. i did that loads of times as a kid. (i had so much fun doing that using a cassette voice recorder and hiding before playing it back!) It probably won't work with an mp3 unless you set a high bitrate. as for the modulation, most mp3's are sampled at 44100 hz, many higher quality ones are sampled at 48000 hz. you should get good results if you record it /losslessly/ at 48khz, crank up the gain, then encode it to mp3 at 192 kbps.
Reply 13 years ago on Introduction
I am rather doubtful that that would work. I'm pretty sure that computer audio cards have bandpass filters to prevent those high frequency signals. Even if not, you'd have to record in very high quality audio. According to the Nyquist theorem, at a modulation of 40kHz, you'd need to record at a minimum of 80kHz. Computers can do (I think) 96kHz, so that is possible, but I still think the sound card won't let that through. However, I'd love to be proven incorrect.
Reply 13 years ago on Introduction
Good idea, but I wanted this to be a stand-alone device that could be reproduced cheaply.
Reply 13 years ago on Introduction
or, make magazine suggested putting it in a sweatshirt and making the switch a zipper. I forgot the issue, but you probably could look up the schematics on google.
13 years ago on Introduction
No crystal or resonator? is the internal timer accurate enough without it?
Reply 13 years ago on Introduction
Oops, forgot to mention that! I changed the fuses and turned off the "divide by eight" option for the internal clock so it could run ladyada's code unmodified. And yes, it seems accurate enough and has worked with every TV I have tested. It might not work in extreme temperatures, though.
Reply 13 years ago on Introduction
What command did you use to set up the fuses? whenever i try setting it myself i brick the chip! did you have to change anything in the code or was just changing the fuse enough?
Reply 13 years ago on Introduction
I think I used this one here at http://www.engbedded.com/fusecalc/
I'm pretty sure I kept everything default except for unchecking the " Divide clock by 8 internally" option.
I didn't change anything in the code because at the time I didn't know how to open up the multiple files and compile them.
13 years ago on Introduction
I'd actually like to see less brief instructions. I think a lot of people would like to build this! Nice job.
Reply 13 years ago on Introduction
Thanks! The thing is, I didn't take any pictures of me building it :-) Maybe I'll make a better version, and take pictures that time...