Wednesday, September 27, 2017

Arcade MAME Spinner

I love Tempest, and I want a spinner on my arcade machine.

Unfortunately, they aren't cheap. It looks like the two main solutions are...

The Ultimarc SpinTrak - https://www.ultimarc.com/SpinTrak.html

TurboTwist 2 - http://groovygamegear.com/webstore/index.php?main_page=product_info&products_id=268

Both of these products start at $69 USD ( *cough* price collusion *cough* )

There are a bunch of DIY spinner articles that involved ripping apart old mice. The one that really caught my eye involved an old VHS VCR drum head.

http://www.instructables.com/id/Spinner-Jog-Wheel-Inside-of-a-VCR-Head/

I bought a couple old VCRs from the local thrift shop for $10 each. Ripped them apart. Extracted drums. The first one I ripped apart was very different in structure than the Instructables article. I put it aside unsure if I would be able to use it. The second one was similar to the article, so I was pleased.

The article made reference to a DIY circuit board, ripped apart mouse, etc, and I wasn't really keen on this solution.

I had read a few things here and there about the Arduino, and decided to dive in. I wanted to make a quadrature encoder. Here are a bunch of articles that I came across:

https://learn.adafruit.com/simple-arduino-based-usb-vid-and-pid-tester/lets-do-this-thing

https://learn.sparkfun.com/tutorials/pro-micro--fio-v3-hookup-guide

http://yameb.blogspot.ca/2012/11/quadrature-encoders-in-arduino-done.html

https://www.circuitsathome.com/mcu/reading-rotary-encoder-on-arduino/comment-page-1/#comments

http://bildr.org/2011/03/various-proximity-sensors-arduino/

https://www.arduino.cc/en/Reference/attachInterrupt

http://makeatronics.blogspot.ca/2013/02/efficiently-reading-quadrature-with.html

https://www.hackster.io/ShawnHymel/quadrature-encoder-demo-dea334

http://wiki.bildr.org/index.php/QRE1113

http://www.robotoid.com/appnotes/circuits-quad-encoding.html

One of my personal problems (I blame my ADHD) is that I don't document enough. So I do a bunch of stuff, and then I don't know why I did it.

I had previously done a bunch of reading on all of this, and a couple months ago I ordered the following components.

330 ohm resistors
10k ohm resistors ( I keep accidentally typing resisters)
QRD1113 photointerrupter
Arduino Leonardo Pro Micro ATmega32U4 w/ USB header - these things are about $5 CAD on eBay. I don't know if there is a significant difference between the $5 eBay versions and the $20 SparkFun version. We'll see when things start to come together if there are any issues with the cheap Chinese stuff.

So I have all this stuff, plus some other odds and ends I've been ordering off eBay for the past few months, and now I'm at the point where I should be able to start prototyping.

I asked myself if I had enough components. The articles I read above included some additional things like 100, 150, 220, 270, 4.7k, 5.6k, 33k, 470k, ohm resistors, 0.1µF (100nF), 1uF (1000nF), and 10nF capacitors. Do I need these things while working on this project?

Tangent! It's easier to type uF for microfarad, but using a 'u' is not accurate. The proper symbol is 'μ'.

μ, µ
Lowercase letter Mu / Mμ; micro sign or micron
ASCII 230
ALT + 230
HTML µ
Option + m on Mac (hmm, maybe it isn't that difficult to type)

Also, ohm - Ω (Mac - Option + Z), unicode U+2126, alt+234. Something, something about Greek Omega -U+038F.

Back on track. Do I need all these extra components while working on this project? It's better to have them on hand than not. I hopped onto Arrow.com, and ordered a bunch of extra pieces. When possible, I splurged and ordered automotive grade components. We are talking about pennies difference here.

100Ω resistors

Don't worry about ammo vs reel - it's just the way they are packaged in bulk. Exact same components. Lower TCR is better, but not necessary in small projects like this.

To be continued...