i have been using max/msp for a while and am really tempted to try out the arduino board.
i am hoping to control an audio motorised fader via osc messages. so the audio that passes through the fader can be gain controlled by the computer/msp.
i am a bit new to this area but i learn pretty fast.
in my sights at the moment are :
You can't drive the motor in the fader directly from an Arduino pin, because Arduino pins can source mac 40mA of current most motors will draw more than that.
You need a few components to drive it, google Arduino + DC motor to find info.
The info on this thing is really sparse, the datasheets are useless
It takes 10V (the motor) and the total resistance is 10KOhm
I suppose the thing works as a servo. To test it you can hook it up with a 10K pot and 10V, turn the pot and see if it moves
If it works this way, then you buy a digital pot that the arduino controls and use it to set the fader value.
here is one of these faders working with max msp.
in tyhe video below, he is moving a slider up n down in the software so the music goes up and down in level and the fader follows this. this fader does not seem to be used as a normal analog fader( like an analog mixing desk) it is only used as a controller fader to control software and for the software to motorise it.
looks pretty cool.
there seems to be 4 connections
2 for the motor ,
2 for the touch sensitive resistance info
2 for the actual analog audio. ( if you use it as a normal resistor for an analog channel)
i see the arduino and max/msp with albeton music software. but as for the bread board on the desk? whats on that i have no idea.?
Looks like it is a 10k linear pot. Depending on the operating voltage of the motor, you might adapt the board from a cheap servo to drive the motor. You might also replace it with a regular pot and turn the pot with a servo.
You tap into the resistor pins, send it 5V and mesure how much voltage is comming back, you map the slider down 0% and up 100%
from an analog input pin.
THis will be the calibration.
Active mode:
Now you find a value that matches with your desired slider value
Call that a setpoint
Loop till setpoint is reached:
Now compare analog in == setpoint
if not then pwoer motor in the direction that gives you value closer to your setpoint (e.g. 10ms left)
(probably best to use PID control here)
Passive mode (reckord slider):
Move slider to desired possision
Push a button to reckord the analog in value, call it setpoint.
That's it
Now make timer software with multiple setpoints to run through and triggers.
i think if i had all the right components i could work it out. If you notice in the youtube video , the man showing the demo of the motorised slider has a few microchips and things on a breadboard
and he seems to be using the same fader as the ones on ebay.
so i think if i buy all this equipment, i would be missing a few parts.
i shall keep googling and post here if i find anything : )
thanks.
You only need: 1X fader,2X npn transistor (for switching 10V motor) and a powersupply (10V), (possibly a button for storing setpoints if you are making a mixer).
multiply this by the number of faders (you use the same powersupply on the faders).
THe guy in the video also had some led display going so he has more components on the breadbord.
Please contact the dude yourself for confirmation.
But the motorized faders are EXPENSIVE if you have to buy them.
(if using ALPS, it's the RollsRoyce off faders)
@ zoomkat
Yes you're right One has to use 4 transistors for this one
You just use 2 pins on the arduino (clocwise and counterclockwise), motor connected to two loops of current (one for each direction). Each loop has 2 transistors (transformer to motor and motor to ground) switched by same pin. Easy as cake
i just watched a tutorial on transistors , by using one of these and a 10v supply i will be opening and closing the circuit . so making the fader move ( on and off) at one speed only, so i would need to make max msp understand and use 'time' to get the fader to where I need it to go.
: if the fader is at the very bottom -100 and i need it to get to 0 max/msp closes the circuit for say 300 ms
:if the fader is at the very bottom -100 and i need it to get to -50
max/msp closes the circuit for aprox 150ms
max/msp can then use the feedback (touch sensitive resistor information to confirm the fader landed where it was supposed to ..if it didn't then max corrects ...and corrects ..until the fader is where is is meant to be. ( as there will be a latency on the feedback real time confirmation might not work?
on the youtube tutorial the guy was only using one transistor to power a bulb ...so i would think id need 2 ( forwards + backwards), i wonder why I would need 4?
Well it's because if you don't, and make 2 loops of current to the motor, You just short the leds (you have ground and +10V connected to one pole of the motor). Hence you have to break the line to the ground too. With two breaks in the circuit you ensure that you don't get shorting to ground. But you can turn two transistors on/off from the same arduino pin, so that's not a problem.
