New project

Is there anyone willing to take me under their wing and give me an education on stepper motors and interfacing and programming them. I have a brainstorm project that involves stepper motors, linear slides, solenoids and possibly some sort of optic tracking device. I need someone that I can explain to what im trying to do and have them tell me what i can do and how to make it work. I have computer knowledge but not much background with stepper motors and interfacing other devices with them. Any help would be greatly appreciated.

Thanks,
Steve

read this; this is articles from microchip on how to encode for steppers.

[www.microchip.com]

also read here about stepper theory. [en.wikipedia.org]

here is the sequence for a stepper motor in full step and then in half step

here is a board that uses bipolor step drivers to control each pin of a stepper motor.

[www.reprap.org]

looks like i need to edit font on that page linked. sorry about that. will fix asap.

I am looking to make an automated pipe organ key holder with optic location so it knows where its at on the keyboard. Can anyone help?

Quote
mcca21
I am looking to make an automated pipe organ key holder with optic location so it knows where its at on the keyboard. Can anyone help?

does it have to be optical?

if you were to 'copy' what's done on a typical 3D printer (for example) you could have an endstop switch at one end of the set of keys, which will then tell the controller where the axis is located. when the axis hits this switch the controller knows where it is (this is called homing)

for example:
endstop switch at position 0 (the leftmost key),
next key up at position 1 (leftmost +1),
next key up at position 2 (leftmost +2)
...etc!

but you'd need multiple fingers to press multiple keys and do a chord though, wouldnt you? and it would have to move pretty quick to play an impressive tune.
I think by the time you set that up you'd be better off making a full rack of actuators / solenoids to press one key each!

all the best with your project tom

My only dilema is that some European pipe organs dont go by a particular standard as far as keyboard specifications go so it makes it difficult to set the machine up to stop at a particular fixed location.

I see what you mean,

with 3D printers the motors are given a setting in the firmware (software loaded on to the stepper motor control board) called steps per mm. this is quite explanatory; say the motor needs to move 40 steps to make the moving assembly travel 1mm.

for your project you could tweak this a bit and use it as 'steps per white key'. that way you can accomodate for organs with fat keys; say 50 steps per key, or organs with thin keys, say 10 steps per key.

for the zeroing bit you could use an optical 'beam break' switch or even a reed switch. these are switches which have no parts touching so won't push away from each other.

the part that breaks the beam could be mounted on a nice and gentle stand with felt feet.. to avoid scratching the varnish on a very nice organ for example!

I can't suggest anything about using a camera for detecting where the keys are because I've never played with anything like that to be honest! and a camera could get affected by camera flashes / bright sunlight, or darkness. I'll shut up now

this sounds like a very interesting project
Tom

Tom,
You seem knowledgeable, I would like to talk to you more at length if I can. Do you have an Instant messenger or something we can use to communicate besides email that is a little quicker?

Is anyone willing to help me with this?

I'd rather keep it on a public thread where more knowledgeable people can chip in, I'm certainly not the most experienced one here! I've only been fiddling with 3D printers for about 5 weeks

I've learnt nearly everything I know so far from the RepRap wiki, wikipedia, stepperworld.com , and this forum of course. Google is your best friend!

to start off with I'd get an arduino uno (cheap if you blow it up, which WILL happen!), and a few stepper motor drivers e.g. the easydriver or a pololu, and a stepper motor or two. the steppers can be scavenged from the older generation of inkjet printers if you have an old one lying around.. newer ones tend to have boring DC servo motors in them.


anyone else have any suggestions?! it's awfully quiet in here sometimes!

as a side note... you may get more help on the Arduino forum, as reprap is mainly for 3D printers i guess