DIY Live » Programming

Video signal generation with PIC chip

Greg Lipscomb — Sun, 22 Jan 2006 23:04:16 +0000

The idea of creating video signals with a microcontroller is very fascinating to me. Creating live video data through software is not an easy task. The task is even more complicated if implemented on a PIC chip. The video signal has to constantly be generated, and any calculations have to be done during a small window of time between frames being drawn. It is much easier to have a hardware video signal generator such as a video card, and then feed the preformed information to it.

The above picture is a picture of a game system created around the PIC16F84. It contains both the video generation software, as well as the game software. This chip is an 18 pin microcontroller made by Microchip. Rickard Grunee writes:
…I have designed the hardware of the PIC game system to be able to run several different kinds of games. It has two standard C64/Amiga/Atari joysticks and video and audio output. The processor is a PIC16F84 running at 12MHz. The description of the hardware is placed on this separate page as it is the same for both of my PIC-based video games. So far I’ve only made two games, Pong and Tetris, but some day there might be more games for the system. (Most unlikely that I write more games though as I probably will write more games for the SX-system instead)…

You can read all about how to generate video on this chip at www.rickard.gunee.com Sadly my new microcontroller programmer will not program the 16F84. I may have to build my own programmer.

I am not going to go into the specifics of how to generate video, because it is very complicated. You can read a good article on it here. The two pictures you see are from rickard gunee’s site. The first one is a sample video signal output from his chip, and the next picture is the output on the screen. The timing of the video signal is very important. The spikes on the signal correspond to the vertical lines on the screen. This signal is the information for one horizontal sweep across the screen. It gives all of the information for one row of pixels. It has on the left, a set-up spike, and then there is an 8 microsecond pause. The other spikes you see correspond to the white, and gray stripes. The baseline is the information for black. This video only has thre shades. The first is black, then their is gray, and then their is white. One warning for this site, is that since it is produced in Europe, it is on the PALS system, and not NTSC, which is the American format for telivision.

Another good resource for creating video signals using a microcontroller (Atmel mega32) can be found here.

DIY pong game

Greg Lipscomb — Tue, 15 Nov 2005 14:19:43 +0000

Well, here is yet another cornell project. Why am I still using them? Because they are cool, and complex, and I really want to make one of these. They use an atmel mega 32 microcontroller. They program the entire game, including the video output to control a television. This is the game that I would love to make. They even made their own controllers. You can see this next picture is a pic of their circuit board.

It is not that complex of a circuit, but if you look at the code, you see it is really hard. They use bitmaps to create the components that move, and they have a bouncing ball program, and just build it from there. You have to keep track of the ball, by giving it coordinates, and if your coordinates match that of one of your paddles, you know to bounce it back at a certain angle. I would love to make this, because it was the beginning of all of our gaming. Anyway, go see the link here for a thorough walkthrough of how it is done.
[link]

Robot follows black tape

Greg Lipscomb — Sat, 05 Nov 2005 03:23:36 +0000

Here is a website that makes a robot that will follow a line of electrical tape layed down on the floor. This is similar to one I made in undergrad. If I can find my notebook, I might put up how I did it. I do have a video of mine somewhere, also, but no pics. This guy’s robot is a little more complex than mine, though mine did have some cool features. It would follow a line, and when it found the end, it would stop for exactly two seconds, and retrace its steps. Mine was different than everyone elses in the class. They all made their robot turn around, and use the same sensor. Mine had a sensor on the back, and backed up along the line. I will look for the video, it is really cool. Anyway, check out this guy’s site. It looks like a fun thing to make.

[Link]

Build a Gps

Greg Lipscomb — Tue, 01 Nov 2005 18:48:46 +0000

Here is a how-to project for making your own GPS. This guy takes a LCD from a cell phone, and a GPS unit, and makes everything he needs for his own personal GPS. It seems hard, but what a challenge.

[Link]

Play mario brothers on your ipod.

Greg Lipscomb — Thu, 27 Oct 2005 21:29:12 +0000

Here is a hack that will let you play your old gameboy games on your ipod. Very cool!!!

[link]