Introduction: Portal "Still Alive" on AVR Microcontrollers

About: I make electronic stuff.Because I Can.
Yet another Portal-related instructable , but Different !
This one shows you how to :  
1)Build a very cheap device that plays an 8-bit version of Still Alive from Portal
2)On the same hardware , but with a different chip , play the "radio tune"

Here are both projects , in the same video (I hope the video quality does not affect how this entry is rated.I filmed it with a phone camera) :
Move on to the next step for the parts list for each of the two projects

Step 1: Parts List

As mentioned in the intro , the parts required for this project are really cheap.
What do you need ?
You need to know how to program AVR microcontrollers
Here's the parts list :
1)A 16 MHz crystal oscillator
2)A 75 Ohm (Or something around that value) resistor
3)An audio jack connector , so you can connect the device to speakers
4)A 7805 5Volt voltage regulator
5)For the 8 bit version of still alive you will need an ATMega16.For the second project , you will need an ATMega644.The parts above are common for both projects.
And the tools list :
1)An AVR programmer
...and that's it.You really don't need any tools , IF you have a breadboard and some wires .
But in case you don't have a breadboard , grab a perfboard , a 40 pin DIP socket for the microcontroller , a soldering gun , and solder everything on the board,according to the schematic (Which is in the next step).

Step 2: Build the Beast

This is extremely easy to build , as it uses a very small amout of parts.
The schematic is common , for both projects.You will only need to change the chip.
For the 8 bit version of Still Alive , use ATMega16
For the radio tune , use ATMega644

Both chips have the same pinout , so in case you are soldering everything to a perfboard , if you want it to ,make both projects on the same board, use a 40 pin DIP socket and swap the chips when you want.
The schematic is attached to this step.

Here are the firmware files for the AVRs:
1)8-bit Still Alive , for ATMega16 : https://sourceforge.net/projects/avrsa/files/StillAliveATMega16.hex/download
2)The radio tune , for ATMega644 : https://sourceforge.net/projects/avrsa/files/RadioTuneATMega644.hex/download

Step 3: Troubleshooting

The hardware is so simple , that you can't really have problems with it as long as you follow the schematic.The only problem that you may encounter is this one :
If the song sounds very slowed down compared to the video
Are you sure you configured your AVR to run on an external crystal ? Try to remove the 16 MHz oscillator.If it still works , it means it's running on the internal 8 MHz oscilaltor , and that's why it is so slow. Configure the fuse bits for External Crystal Oscillator (Leave all CKSEL bits unprogrammed).

Step 4: This Was a Triumph !

If you successfully built it and it works , then congratulations , the enrichment center is very proud of your huge success ! We are throwing a party in honor of your success.The companion cube is also there (Portal joke.Couldn't resist.)

Anyway , I hope you liked this instructable :)

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