$4 DIY TV-B-Gone

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 a kit, and has the code as well as the schematic on their website.

UPDATE! New version available with full building instructions! http://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

So if you are on a bare minimum budget, you could only use the microcontroller, switch, and one IR LED.

Tools:

• Soldering iron with solder
• Helping hands (recommended)
• Computer with programming software and an AVR programmer

You can look at the pictures to figure out how to solder it together, just make sure you put the code on the chip before hooking it up!

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!

Comments

[JKPieGuy]

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.

[degenstamm]

how meny ohms do the resistors have

[dark sponge]

It depends on the specs of the LEDs you are using. Try http://ledcalc.com/

[purpulhaze]

You omitted the resonator in this version. How?

[dark sponge]

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.

http://www.instructables.com/id/350-DIY-TV-B-Gone-Mico/

[Culturespy]

I'd actually like to see less brief instructions. I think a lot of people would like to build this! Nice job.

[dark sponge]

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...

[Culturespy]

That'd be great! It's pretty close as it is and I think you aren't alone on the budget. At $4 its a fun gadget you don't get nearly as upset about losing or having confiscated. ;)

[dark sponge]

It could go even cheaper (and smaller) with the redesign, it doesn't actually need filter caps and the LEDs I used were a little overpriced! A coin cell battery would make it smaller than a person's thumb! I'm giddy with excitement!

[dark sponge]

Okay, thanks! Due to the demand for an Instructable, I ordered more parts from Mouser (should arrive tomorrow) and I will make multiple versions of the DIY TV-B-Gone in Instructable form for all to enjoy.

[dark sponge]

Thanks! More DIY TV-B-Gone Instructables to come...

[dark sponge]

I have a working prototype! After a long time of wondering why it wasn't working I discovered the true value of filter capacitors :-)

[Callum Snowden]

Encase the whole thing in surgu (including the button but except the LED's) and just mark on the surgu where the button is then it would be almost perfectly discreet but just slightly hard to change batteries unless you cut a hole and get a battery holder :)

[dark sponge]

An excellent idea that I wished to do on my new model (http://www.instructables.com/id/350-DIY-TV-B-Gone-Mico/) but I didn't have any at the time...

[dark sponge]

Awesome! I was already thinking the same thing without sugru but the sugru is a great addition for both durability and aesthetics!

[Unpaid_OT]

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!

[omnibot]

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.

[Vick Jr]

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!

[Vick Jr]

Also see this on how to make a "40 kHz IR carrier using 20 kHz audio".

[duckythescientist]

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.

[GrotBox]

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.

[joe57005]

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.

[dark sponge]

Good idea, but I wanted this to be a stand-alone device that could be reproduced cheaply.

[piedoom0]

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.

[joe57005]

No crystal or resonator? is the internal timer accurate enough without it?

[dark sponge]

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.

[joe57005]

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?

[dark sponge]

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.

[kelseymh]

That is sweet! Are there button batteries with enough current output that you could drop the AA pack in favor of a self-contained unit? The 21/23, used in key fobs, is 12V, so a bit much for the LEDs.

[dark sponge]

Thanks! Yes, I'm sure a button or coin cell battery would have enough current. I just used AAs because they are cheaper, last longer, and are more readily available. A 3v coin cell would probably work perfectly... If you order the parts in bulk and tweak the code a bit... TV-B-Gone throwies for $2 a pop?