Unimplemented Trap
Adventures in hardware and software

SB181: A 74LS181 based “logic operator”

A sort of 8-bit calculator that takes hexadecimal input and displays the results in both hexadecimal and binary. All done with 74 series logic and no microcontroller or CPU and makes for a handy companion for the 8 bit programmer…
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1-bit CPU with the MC14500B industrial control unit

I came across this weird chip a few months ago. Designed by Motorola in the 70s, its purpose is to replace the “ladder logic” relays in industrial process control so all it needs to do is make simple decisions based on whether different inputs are logic high or low. Curious to learn more, I built a small single-board CPU around it…
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“Programmable” LED Matrix Driver without a Microcontroller

A quick weekend project to see what I could make work with the parts I had laying around. This one’s been in the back of my mind for a while so it was time to give it a shot. Using some basic logic chips, 555 timer, and an old static RAM chip, I put together this circuit which can display any pattern you can fit on an 8x8 LED matrix…
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Modding a sheet metal brake into a box and pan brake

I’ve been using the Clarke brand vice-mounted sheet metal brake for a few years now and it’s been useful for various projects and handled both sheet aluminium and steel without issue. But more frequently I found myself wishing I had a real box and pan (sometimes called finger) brake for when I needed 2 folds on the same corner…
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ebd: Eight Bit Dump - A hexdump utility for 8 bit software development

ebd is a simple tool I wrote in Python for viewing the source of a binary file in hexadecimal. Ideal for working with 8 bit ROMs etc.
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