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Q*Bert Knocker writeup, correct me on parts

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1UP:

--- Quote ---Hehe, that's what I need:)
--- End quote ---

Dav:

--- Quote ---i have considered other options.

What's a 555 timer?
As that might be something better to put in my schematic.

So you know how to do that counter thing with interrupts in mame.
--- End quote ---

Beley:
Here is something i made to run stepper motors off of the parallel port a while ago.

It uses 2 ULN2003 chips,they are Darlintion arrays and can handle up to 50V and 500mA, meaning that it could drive some big lights or perhaps the most useful would be to drive relays which cannot be driven directly by the parallel ports 5V, there are 12 outputs and 5 inputs, sorry about the lack of a schematic but i never made one , only this PCB layout  

Bren R.:
SP - seems the BEST idea (I'm never one for "easy" or "cheap") is to use your choice of port:

I'd say serial, some people use parallel to turn on their arcade monitors once sync is stabilized and Scroll Lock, well, god forbid someone should HIT the Scroll Lock key in WIN and end up burning out your solenoid.

A 555 timer chip is a good idea, fixes the problem of how fast to send the 255/0 (especially with future advancements in processor speeds) but will take some work to get the component selection right.

The same setup could be used for any number of pieces of feedback, D0 (1) for QBert, D1 (2) for APB lights (using more 555 timers to blink them), D2 (4) for... etc.

Document them and make them a standard.

Bren...

SirPoonga:
I like Bren's idea.  The timing should not be done in mame.
IF so happen mame crashed while the port or led was turned on you will have a constinant flow of electricity going to the solenoid, that's not good.

I like the Weeder Tech thing.  That's what's needed.  It sounds like that does the timing for you, you just have to signal it.

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