[PD] electro-mechanical piano (player piano) - Arduino, Solenoid Issue

[Epic Jefferson]

Hey guys,

updating on this project. I got the pwm shields and i've hit a wall. The
driver circuit I'm using to control the solenoids via arduino is this one
from instructables
(link<http://www.instructables.com/id/Controlling-solenoids-with-arduino/)>)
and
it uses a single pin to control the pwm signal.

The pwm shield (link<http://www.practicalmaker.com/products/arduino-shields/pwm-shield-assembled>)
is
based on the tlc5940 which requires each pin to have it's own ground
instead of a common ground across all drivers. This is a problem because
all of the information i've found suggest that the signal from the pin
controls the gate (transistor - TIP102). But i think, in the case of the
tlc5940, the 5v supply is constant and the ground is being controlled,
that's why it works perfectly for LED's but seems to be ill suited for this
circuit.

Any suggestions on how to modify the instructables circuit for use with the
shields? or would the circuit have to completely change?



On Sat, Jun 29, 2013 at 8:35 AM, Charles Goyard <cg at fsck.fr> wrote:

> Hi,
>
> Epic Jefferson wrote:
> > i've been able to control solenoid velocity with pwm via pd, this is also
> > how Winfried does it. Also, motors are way too loud, as I told Olivier.
>
> That's good to hear ! How much accurate is this ? Underpowering a hub
> magnet that has a lot of jitter in its movement [1] sounds like it would
> not
> provide repeatable action. I'd be glad to be wrong.
>
> Cheers,
>
> --
> Charles
>
>
> [1] What I mean is: you can shake laterally a unpowered solenoid and get a
> lousy
> maracas.
>
>
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-- 
www.epicjefferson.com
www.avmachinists.org Puerto Rico based Art Collective/ Non-Profit Org
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