Thread by @reconbot

Starting my hunt for serial equipment in Seattle. I only have two places on my list so far. Goodwill and RePC

Goodwill is a bust but they did have some neat stuff

I called RePC Seattle and they said “our other location has the old stuff” promising 🤞

“We have a bin of them, 99c and up” RePC Tukwila

🙌

REPC was amazing! Let’s start with my childhood computer. It’s an IBM 8086. My mother swapped the floppy drive for a 4mb hd and upgraded it to an 8088.

RE PC is a computer recycling store that uses their incredible wealth of parts and space to do the appropriate things. Also they print signs.

At the entrance they had a few teletypes which were fantastic to look at. (Not pictured here a 40mb drive larger than most desktops I’ve ever owned)

This horrible photo of a nonplussed child has 1/3rd of the inventory pictured.

He was more excited by the gamepads

And the electric typewriters

So I went searching for serial mice. DAT drives anyone?

If only I had a warehouse of my own... Fun story, a fancy Manhattan loft has a permanent oscilloscope I salvaged with help from @TVCOG from GE(?) that nobody could move when we left

Hahaha if only you knew kid

Pay dirt

So I had a few options. My goal is to make a serial mouse driver. From my blog post researching the protocols I know there were at least two versions of the mouse protocol. Microsoft’s 2 button and Logitech’s 3 button.

Honorable mention was the trackball my mother got to fight Carpal tunnel. Also because it looked cool. This was a two button mouse with one button. I *almost* bought it but it’s too big for my suitcase.

It was a tough call though. “What are you going to do with it?” My wife asked.

I ended up with the knockoff Logitech and the ms mouse.

I also snagged a serial barcode scanner because, why not? I really hope it goes *beep*

I don’t actually have a 9 pin serialport to USB adapter with me on this trip. I do have a bunch of serial UART to USB adapters for 5v serial. Most of them only have RX and TX (which is fine for the mouse) but all this equipment runs on 12 volts! These days 3.3v is standard.

(It's really cool how 3.3v and 5v devices usually work together allaboutcircuits.com/textbook/digit… except for some things like the raspberry pi where it dies at 5v, that's not fun)

The blog post I wrote analyzing a 22 year old page someone made about the then aging serial mouse protocols can be found here roborooter.com/post/serial-mi…

I get my DE-9 to usb-c converter Thursday just in time for the plane. 🤞🤞🤞

I really like this ascii diagram. The useless second byte is all about synchronizing packets. The useless first byte is anybodies guess.

Other things I couldn't buy because of travel.

1) A "till display" from a cash register that shows you in 7-Segment glory how much money you owe
2) A Flux capacitor (they had huge capacitors)
3) A 102 key break spring keyboard
4) A huge joystick with lots of buttons
5) An Atari

*Bits* not *Bytes* in that ascii art thing

And lest you think I drag my son to things he hates, we bought him that mini keyboard too.

https://twitter.com/opheliasdaisies/status/1163652313543692290

That "lets ignore the first bit" of the mouse update packet bothers me a lot. The best I can fathom is that some other widely used device (keyboard, printer, monitor?) used the first bit and this was a easy way to identify devices or ignore bad input.