NoTrueSpaceman

Aka “ADDDA” or "AuDiDeDrAr" or "aww dee dee drawer" or "A3DA"

I've had this idea bouncing around in my head that you could use 1-bit wide DRAM as a delay line if you simply counted up through it's addresses, reading and writing as you go. 1-bit wide DRAM like the M3764 have separate pins for Data In and Data Out which makes the read-and-write method easier.

The light bulb moment was coming across an old post on diystompboxes.com where one commenter provides a short snippet of code to do a Delta-Sigma analog to digital converter using the Arduino's analog comparator pins. I had planned to do this purely in software by using the normal ADC pins and then calculating the Delta myself. But the built-in comparator makes this dead simple!

I have a small collection of vintage calculators that I stumbled into collecting. I found one at a garage sale, and then one was given to me, then I found a neat one on eBay for a good price… Before I knew it, I was a calculator collector.

I actually use most of them despite having a great calculator app on my phone because I prefer their physical interfaces. I have one on each desk and one in my bag so I don’t have to go searching. I don’t have that many bags and desks though so there is also a small stash in a drawer.

My latest addition is a National Semiconductor 4510 Mathematician from the mid 70s. It has an 8 digit red LED display and runs on a 9 volt battery. There is a jack on the top edge for connecting a wall supply if you’ve got a lot of math to do.

It is in great condition and the seller even included a brand new battery. It is one of the lesser RPN calculators of the 70s and not expensive. Like most of my collection, is not valuable but it is uncommon.

Todays notebook sketch is some ideas for building a tape “transport” - the mechanical bits that move the tape around in the right way and at the right tension. I have a weird fascination with magnetic storage media and tape in particular. It was a…

Conway’s Game of Life (CGoL)has always fascinated me. It is probably the most well known of all cellular automata and also probably the most intuitive. Yet even simple patterns can turn into complex sequences of shapes, patterns, and noise. Years ago, when learning about the…

If you’re interested in the early history of computing, check out Turing’s Cathedral by George Dyson. It covers an interesting middle phase between the original electronic digital computers and the wide commercialization of computers in the late 50s. Specifically it examines the people and development…