MF Module preview

[T.K]

For all who are interested: the MF module is up and running

Schematics and PCB layout can be found on the MBHP MF page http://www.ucapps.de/mbhp_mf.html

The first alpha firmware will be available as soon as I have more sparetime again.

Here are some informations for the guys who want to upgrade their existing MIDIbox MF: in difference to the old design the motors are now supplied with 8V. So, you need a LM317 regulator to adjust the correct voltage. With higher or lower voltages the faders will not be moved correctly, since I calibrated the PWM generator for this voltage manually. In worst case (all motors are active), the current load is about 1A!

With my current test program, the motorfaders are repositioned very exactly with a 8 bit resolution (planned:9 or 10 bit) in less than 0.5 seconds. There is only one imperfection: they are not moved with exactly the same speed. This is not a software problem, but a mechanical problem (I exchanged the faders to ensure this). I will try to implement some kind of automatic calibration which tries to find out the optimal PWM table values for each fader seperately - an interesting task

Best Regards, Thorsten.

[LO1]

Couldnt be better timing

My motor faders turned up on Friday!

Thanks for all your work so far!

: ;D

[banneduser]

looks good, so will this allow all faders to move at the same time? or is it still sequentially? i guess if it’s still sequential, it’d be possible to do concurrent if i chained cores together…

[banneduser]

I will take the liberty of answering this question: YES! The faders move in parallell, you can have 8 faders per core module.

Thorsten solved this by adding a timer interrupt every 250 us that deals with the fader A/D-conversions, leaving the main routine free to just concentrate on the actual position of the faders (that is - checking if they’re in the right place, and if not how fast should they move towards this right place).

[banneduser]

yay!