Scratch wheel

[Turnthetables]

alrighty guys! here I go, I ordered my core kit from smashtv... should be here soon. I'm getting the sensors from some old mice... now stryd_one, you said that the encoder should be a module.. could you enlighten me on how to do so? I would need either a din or an ain? correct? Any help would be super appreciated, I'll post a picture guide of my build :) (people on the interwebz usually like pictures ;D)

This place rocks!

[rasteri]

I think the only thing you'll need to do differently is remove resistor R9 from the midibox core module, everything else should be fine. If you have any problems, either post on here or PM me and I'll be more than willing to help.

I'll draw a new schematic soon, I'm in the middle of making a website for my various projects.

I haven't tried torq 1.07 - they might well have fixed the midi bug that was present in previous versions.

[Turnthetables]

Rasteri! I'm a web developer! If YOU need anything web related PM ME! Should I have gotten the 20 or the 52? will it matter? I took apart a mouse and it had three sensors, I'm going to post pics, two are the same ( for the ball) and one is larger (for the scroll wheel) would it matter which I use? They are all, whats its called, quadrature encoders? my plan is to build a DIN for the sensor and MAYBE an AIN for some pots. Just to make this controller nasty! first, I have to get it, then I worry about extras!

does the bushing provide smooth operation? I saw a schematic on here with a skateboard bearing, that would still work for the touch sensor correct? Also, It looks like It's going to be a lil bit before I get my hands on some touch sensitive paint. ( I forgot the name :) ) Could I build it non-touch and then when I get the paint, make it touch sensitive?

Thanks for the help!

[stryd_one]

stryd_one, you said that the encoder should be a module.. could you enlighten me on how to do so?

I was referring to the driver software ... don't worry about that for now :)

BTW, you can't use a DIN module to connect the scratch encoder... It connects direct to the core module.

[Turnthetables]

the sensors ( rotary enc and the touch) are going to go to the j5 connector port correct, according to smashtv's doc on his site it says can be used for digital in or digital out....

my next question is , why no  r9 resistor, what does that do? thanks for answering my questions guys.. I'm pumped, rasteri was right! you guys are crazy helpful!

[stryd_one]

J5 yes, but that's not a DIN module ;) Also, it's not being used as a digital input, but as an analog comparator. This is because rasteri has found that the optical encoder's output does not swing far enough to provide appropriate digital logic levels.

R9 is a pullup resistor on the DIN chain. I'm not sure why you'd need to remove it, I'll leave that one to rasteri as I don't have his schematic handy.

I'm glad you're having fun :D

[Turnthetables]

ok cool, I remember reading that it could do analog or digital, now I've looked at this thread  a bunch of times and I'm confused about the PIC, will it run on the 52 now? I remember at some point it wouldn't...... or the 20... I'm not sure what I read now, but I just want to make sure that the chip I got on the way, will work! I got a 20 on the way.....

EDIT: I have a 20 on the way not a 52!

[stryd_one]

20? 52? huh?

[Turnthetables]

18F452 18F4620..... my bad ;D

[rasteri]

18F4620 is the recommended chip, as it has built-in comparators that make the wheel track better.

The bushing squeaked at first, but polishing the stud made it stop. (I just put the stud into a drill and spun it

while holding a brasso'd rag to it). I have no idea if a skateboard bearing will work, but as long as there's electrical conductivity between the spinning part and the stationary part it'll be fine.

Removing R9 is to compensate for me not having a DIN module, and thus not writing the touch sensor code the traditional MIOS way. Everyone must suffer for my cheapness.

[Turnthetables]

well, I'm sure stryd_one wouldn't mind helping me figure out what needs to be changed...  ;) the acetate sheets you used, were they as thick as a CD/DVD? or were they "filmy" ? I also plan to make the platter the size of a cd, could I scale down the encoder wheel or do I need a new one? Thanks for all your help rasteri!

[stryd_one]

I'll help as much as I can. Rasteri is the expert here, I'm just trying to save him some time by answering questions, so that his time is available for working on other cool stuff (like traktorizer compatibility). I'll often have to leave the really specific stuff to him ;)

The bigger the encoder disc, the more accurate you can be with it... So if it fits mechanically, then leave it how it is :)

[rasteri]

You could probably scale down the encoder wheel down quite a bit as long as the encoder strip is quite high-res.

[Turnthetables]

Ok, mine is probably going to end up being like 5.5 inches or close to that...  when I build my MBHP i could essentially test with just an encoder wheel and my mouse sensor correct.. make a spindle for the encoder and spin it...  I'm going to try to make a few different sized encoder wheels and test them out..... I want to try CD size, a little bit bigger and 7 inch....  Do you know if there is a list of mios functions around? I want to study rasteri's code , I understand the syntax, but I would like to see like a list of mios functions if at all possible... does anybody know of one?

[rasteri]

http://ucapps.de/cmios_fun.html ;)

[Turnthetables]

thank you much sir... tallyho... I just always wanted to say that... do ppl on the other side of the pond say that alot?

[Theta_Frost]

other cool stuff (like traktorizer compatibility).

The dumb way I see it, couldn't you just route this nice encoder and stuff, through a jack on the bottom of the traktorizer, and using a switch to switch it?  I think it would work.;)

[stryd_one]

thank you much sir... tallyho... I just always wanted to say that... do ppl on the other side of the pond say that alot?

I say it whenever I'm flying towards a focke-wulfe with the sun behind me.

The dumb way I see it, couldn't you just route this nice encoder and stuff, through a jack on the bottom of the traktorizer, and using a switch to switch it? I think it would work.;)

It's just a planning/coding issue - like, making sure the required pins are available in the standard design without mods, making the software support the high-res encoder driver module by using a makefile-specified #define, creating said driver module, etc. Nothing difficult, will only take a couple of hours in the chatroom :)

[nILS]

Sorry for the OT.

I say it whenever I'm flying towards a focke-wulfe with the sun behind me.

ROFL. I don't usually roll around on the floor a lot but that one did it ;D

Nothing difficult, will only take a couple of hours in the chatroom :)

"Yeah, we do all our programming in the chat room - it's like a real-time SVN"

[stryd_one]

Hahahah realtime SVN is right :)

heh, I originally wrote messerschmitt (mmmm, bf-109. Lovely.) but focke-wulfe seems so much more obscene :D

Pip, pip, tally ho!

[Turnthetables]

Ok,  my MBHP has arrived! Woohoo! I'm going to build tommorrow with my electronics/programming buddy who is interested in what I'm up to. What needs to be changed in the code for it to work with this r9 resistor in place?  I'm willing to write code ( would be my first Mios app, but I've coded before) if you can explain what needs to happen... psuedocode or words.. anyhow you want to explain....

[rasteri]

Line 108, change :

capsense+=PORTDbits.RD1;

to:

capsense+=PORTDbits.RD0;

Then wire the touch sensor into pin RD0 instead of RD1. That enables you to keep R9.

[Goblinz]

thank you much sir... tallyho... I just always wanted to say that... do ppl on the other side of the pond say that alot?

Not really, it's a fox hunting term. Only seems to be used when people are taking the piss.

Any chance of some MP3 samples of this.

I was wondering if there's some way to "increase" the resoulution by having certain marker quadrants (ie red markers with black ones every so often and a a seperate sensor with a red filter) so that a PIC could be used to add extra pulses. IE 2 Marker quadrants within a certian time would give 20 pulses. Just a suggestion, prolly don't know what I'm talking about.

[Turnthetables]

My Midibox is almost done, I'll post pics soon... Now Rasteri... I cam across this recently and I was wondering if this would work...

http://www.instructables.com/id/HDDJ_Turning_an_old_hard_disk_drive_into_a_rotary/

It's an Instructable about using a HDD as a Rotary device.... I Have 3 Old HDD's laying around that I'm willing to bust open but, my question is... they add "comparators" to the unit. The Midibox chip has them built in correct? your code uses um, So could I just wire up a HDD in place of the optical encoder and get the same results?

Thanks,

TurntheTables

[rasteri]

Yeah I saw that story. There are a few problems involved in using an HDD motor for this project -

1) They have a much lower resolution than we need - something like 400 steps per resolution, which isn't really enough IMHO.

2) The signal they produce is different - it uses 3 lines instead of 2. Coding around this would be pretty easy, but *I'm* not going to do it because of reason 1. Feel free to have a go yourself.

3) Related to point 2, the PIC only has 2 comparators. They can be multiplexed, or you could just use external comparators like that guy you linked to did.

In all honestly, you're better off with an optical encoder. Those HD motors make great bearings though - you could attach an encoder wheel to it perhaps?