Introduction: TV B Gone Keychain

Recently I thought about shrinking my TV B GONE which I made by myself using originall Adafruit schematics and their firmware 1.2 (include EU codes)
I saw many projects on the Internet but only a few was designed for use with European on/off codes. (Yes, I'm from Europe - Poland)

I found dark sponge's projects. Especially I found this one very helpful

In the last 20'th step he did some upgrade to work with original adafruit firmware v1.2.
I did my own schematic mainly based on his.

TV-B-Gone is a super simple universal remote control device for turning off a large majority of the current available brands of television sets
about 85%. It was created to allow people in a public place to turn off nearby television sets. Its inventor has referred to it as "an environmental management device". The device is part of a key-chain, and, like other remote devices, is battery-powered. Although it can require up to 72 seconds for the device to find the proper code for a particular television receiver, the most popular televisions turn off in the first few seconds.

Step 1: Things You'll Need

Things you'll need:

  • 3 led keychain flashlight
  • soldering iron
  • solder
  • copper clad
  • B327 etching solution or other
  • 3 IR LEDs 5mm diameter
  • flexible wire
  • 3 AG9 (1.5V each) battery (connected in series which gives 4.5V)
  • BC556 or other PNP transistor
  • utility knife
  • AVR ICSP programmer (i used USBasp)
  • Programming software (I used AVR Burn-O-Mat V2)
  • a lot of patience
  • ATtiny85V-10SU (I used ATtiny85-20SU which works from 2.8V, but ATtiny85v-10SU is better because it works from 1.8V)
  • 1k resistor
  • 10k resistor (if you are from Europe)
  • tactile switch
  • slide switch

Step 2: Get a Flashlight Keychain.

I had a 3 LED key-chain flashlight for 3PLN (~1$).

Inside I found a simple circuit with 3 white LEDs,battery and tactile switch. The fake solar panel was unconnected.

I measured original PCB circuit and placement of button and IR LEDs. Then I started to arrange space on PCB.

I use CadSoft Eagle for PCB making purposes.

Step 3: Work on Schematic and Board Layout

As you can see I decided to use 3 IR LEDs. I didn't use capacitor between VCC and GND and I deleted external oscillator. I also decided not to place PNP transistor on board. (BC556 - popular in Poland)
I connected it with jumper wires to certain (corresponding?) points on PCB.

Step 4: ThermoTransfer and Etching Process

I won't describe the process of thermotransfer and etching because every electronic-hobbyist should already know how to do it.

Step 5: Programming Attiny85

That was tricky. First I soldered wires to Attiny85-20SU and then through breadboard I programmed it.

Download FIRMWARE V1.2 from original project page

Burn hex file into microcontroller with your programmer. I used USBasp and AVR Burn-O-Mat

Remember to program fusebits to internal 8MHz clock.

1. Browse for firmware .hex file

2. Write hex to uC.

3. Go for FUSES

4. Make selections as mine.

5. Write Fuses

6. Done

Step 6: Solder Parts to PCB

Solder all SMD parts, then IR LEDs and then transistor and battery pack.

I decided at this point to add slideswitch on GND line between battery and PCB for battery saving purpouses.

Step 7: Assemble All Parts

Use your head and think how to manage space inside the keychain. I did it that way - PIC REL.

I connected 3 AG9 batteries in series which give 4.5V :)

The transistor I used is BC556. If you use diffrent PNP transistor make sure you know where Emitter, Base and Collector pins are.

Step 8: TVB GONE Keychain Is Finished

That project brings me a lot of fun. I learnt new PCB planning skills. Working with SMD was tough because of extremely small size.

In advance I want to apologise for my bad english. As I said I'm from Poland :

Here you have my Eagle files.

Step 9: Clean All Mess You've Made.

Here is my desk after i finished project :D
As you can see it's a total mess :D

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