IDEA: homebrew computer

[john-s]

Why not do an episode on something related to homebrew computers?

Back when the hombrew computer club was around in the 70's lots of interesting projects grew out of it, including the Apple I from Wozniak.

So, what is happening on that front today. I see a lot of people that are into digital electronics are making embedded devices or are playing with microcontrollers (on which we already had an episode), but I see very few out there that are actually designing something like a fully-fledged desktop computer.

I'm sure that is partially because modern day motherboards in PC's have grown so complex with all their multiple layers of circuitry, that it would be next to impossible to create an equivalent in your garage.

However, the components and techniques available to your average (or not-so-average) hobbiest today are far more advanced than those in the late 70's. So what could be accomplished today? I can't help but wonder.

Many people I see that are involved in building homebrew computers are either building replicas of classic old computers (think z80, altair, etc...) or are working on small embedded devices.

It would be neat if systm could find someone that is actually dedicated to building something as advanced as possible, and as close to a desktop computer as possible, with modern-day electronic components.

It would also be neat if people could post links to such projects in this thread - even if the geek factor is a bit too high for systm on this one, there would still be some interesting links then!

[computoman]

It would also be interestiang to see how people put older computers back to work or how to do more useful things with your existing machines. I have an old p1 is use as a security system. I have wired the joystick port for the buttons to one of those magnetic door switches. I can tell when a door is open, closed and how long the door was open. what is really neat is if you have it connected to the internet, you can send your self email or sms messages about the door or windows opening or closing. Makes it easy to call the police to come check your place of residence even on vacation.

[john-s]

It would also be interestiang to see how people put older computers back to work or how to do more useful things with your existing machines. I have an old p1 is use as a security system. I have wired the joystick port for the buttons to one of those magnetic door switches. I can tell when a door is open, closed and how long the door was open. what is really neat is if you have it connected to the internet, you can send your self email or sms messages about the door or windows opening or closing. Makes it easy to call the police to come check your place of residence even on vacation.

That is indeed interesting, but something entirely different of course. I have two sets of industrial relais thingies that you can hook up to an LPT (printer) port. They can switch 220V(I got them in Europe, but I suppose 110V would work just as well.), so you could, similarily, send yourself an email to turn on the lights in your house, or switch whatever else you can hook up to an outlet. There's more modern versions of these things out there that you can get. (google: "relais card" or "triac card").
Velleman sells this nice kit to build your own triac card which lets you use a computer (or other low-voltage circuit) to switch appliance-voltage stuff: http://www.arcade-electronics.com/detail.aspx?ID=17667.

More on topic, I found this while browsing: http://www.mycpu.eu/ That's the closest I found to a homebrew desktop computer so far. It runs a DOS-like OS and is capable of VGA graphics. It was featured in make magazine's blog (http://blog.makezine.com/archive/2007/07/the_mycpu_homebrew_comput.html) where it is mentioned that it was built using only 74HCxxx chips (except for the EPROMs, RAMs and UARTs). In other words, they tried to not use any modern microcontrollers. So it's not even near the top of what you could build using modern components. Very impressive and interesting nonetheless, and makes me even more curious what you could do with more modern chips.

[goldfingermafia]

Yes, It would be nice to see a simple micro computer build. You could easly do this for under 100 bucks, using a 68000 up and two 2732 EPROMS, and a 6821 I/0 controler. showing how to design and build this sytem would be awsome, it would be an indepth show that would probully span multiple epasodes, but would really open up the eyes of a lot of normal people to show them how a computer works. This is about the easyist computer you can make.