Any Way to Read Reel Positions?

[nizo]

All-

I have just stumbled into this amazing community; there is a Babel machine sitting in my dining room that I plan modify to use in an art installation (I was really amused to read about qwarzin's God mod!).

The idea here, though, is that the symbols on the reels get replaced by 18th c. wood cut illustrations of a man's mouth/throat producing phonemes--when a reel stops the phoneme is "pronounced," and when all three stop the combination is spoken. I want to weight the distribution so that recognizable English words tend to pay off...

First: To do this, I need to know where the reels stop and be able to send that data to a computer. Now, I could just put some low friction continuous-turn rotary encoders against the reel edges and take readings with something like MakingThing's Teleo system (which I already have), but that seems really inelegant. Anybody have any better ideas? Is it possible to take the signals off the PCB directly? I'm pretty good with software, but consider me a n00b as far as electronics go.

Second: My wife and son (and secretly, me too!) are now totally hooked on Pachislo and they are begging me to make any alterations completely reversible after the exhibition, so...anybody know where I can pick up a set of reels for an Eleco machine that I can modify them and swap out with the original reels?

Okay, this has gone on way too long for a first post. I have already learned a lot from reading here (how to do volume control, it's okay to turn the reels by hand (I was counting clicks and carefully rotating them back to the same positon!) and other good stuff) and am really happy to have found such an interesting an helpful group. Any pointers or comments very welcome.

Best Regards,
nizo

[RKnarr01]

Welcome to this great community,

I'd contact Milt from www.stealthhomeamusement.com , he's the owner and most likely he can help you out with the extra set of reels.

[Tony Junior]

Welcome, Nizo! No ideas from me, I just collect and play them.

[electronrancher]

there's a couple ways to do it. the machine gives a blanking pulse through an optical sensor each time the reel passes through the seam - they line it up this way on purpose, of course.
when the pachi senses that the reel passed the 0-mark, it begins counting pulses to the motor, so it knows where the reel is at all times.

snooping this is probably doable, so you could always count milliseconds to the next blanking pulse to figure out the symbol... but you might want some simple combinational logic that always outputs a code for each symbol, rather than having to watch for a blanking, and know it's 200 steps away.

since the reels are on a little removable slide, and don't have center spokes for the most I've seen, you could probably build up a little ring of cardboard or black plastic, and punch holes to designate each symbol. how many symbols does your machine use (and can it stop on blank spaces?)? These holes would be read by a set of LED opto detectors, which would see a reflection if a hole was absent, or would not see a reflection if a hole was present - kind of like a CD.

I would probably use 4 or 5 holes in series, binary or gray coded, whatever is easier for your downstream logic.

let's say that you have 21 symbols - this would take 5 holes per symbol in binary code, with the holes appearing or not appearing to designate one or zero
Code 0- xxxxx no holes - binary 0, Cherry
Code 1- xxxx0 one hole - binary 1, Single Bar
Code 2- xxx0x one hole - binary 2, 7
Code 3- xxx00 two holes - binary 3, Jac Symbol

And so on and so on. In it's simplest form, the decoder would read each reel and output the address (binary code) to a simple wav player - could be as simple as having the wav stored in an eprom and dump to a dac with no processing, etc, and the 5-bit address chooses the eprom address.

for example, if you use a 64k eprom, and the top 5 bits are fed directly from the reel reader, you can store 32 2k samples - plenty of room for things like
" Yuuuu" "Suuu" "ccckkkk" or any endearing phonemes that pop to mind.

Now the choice of when to play this sample is trickier - you could snoop the buttons but the reels don't stop instantly because the game is a dirty cheater. You'd have to wait about 20ms or so, then read the reel decoder and play the sample - I don't think a human would notice the delay, though.

The "cleanest" way might be to do it all in a PIC processor, but that would require that you love assembly (or C, ugh - ghastly for an MCU, but in hard times...) and also that you want to bone up on your MCU programming.

Let me know - I'd be interested in helping crank this bad boy out, it "sounds" like a lot of fun.. hahaha sorry I had to.

[nizo]

Fantastic! Thanks for all the great ideas!!

I've been mulling what you've suggested. I do indeed have 21 positions on the reels, and they always stop at "whole" positions, so the 5-bit encoding would be just fine.

Do you happen to know if there is such a thing as a refelctive sensor that gives a fairly linear analog voltage that would be accurate to within 5%? The digital scheme (unless I'm grossly misunderstanding) needs 15 sensor (3 reels X 5 sensors) channels (which I can do, but at some expense) but an analog scheme reading grayscale values of "cards" affixed to the built-up discs you suggested would only require 3 sensor channels--one per reel (which I already have).

The "channels" I'm talking about are important becuase even though I appreciate the elegance of a 'sticking samples into an EEPROM' approach, I'll be wanting to get the data into Max/MSP running on a Mac or PC both for flexibilty and further processing (I'll need to account for diagonals since it's a 3-line machine, and I may want independent samples for individual phonenmes vs. the blend of them being pronounced together, or may want to vary the amplitude of different combinations for example).

Again, many thanks for the help!

-nizo

[Sid]

Hi Nizo,

Once you have finished with this project would it be possible for you to post a few videos etc of the machine in action..

WOW... sounds really interesting.. i am sure others would be interested in seeing the final product too..

Pachi art

Sid