[TriEmbed] Question concerning a mechanical release

[Rodney Radford]

If only controlling the release of ball bearings on a track, the simplest
approach may be a single R/C servo with an attached wand that can be
controlled to lift up, let the ball roll through, and then drop to catch
the next ball (I assume there is more than one).

And yes, it is possible to control *one* R/C servo on the Raspberry Pi
without additional hardware using the PWM channel (lots of references
online via google).

The idea of the solenoid will also work, but the spikes from a solenoid can
be rather nasty, so there will need to be some isolation between the RPi
and the solenoid.  I would not recommend using the 3.3v or 5v supplies
through the RPi, and you should put a diode across the solenoid to help
ease the spikes when the solenoid returns back.




On Tue, Sep 24, 2013 at 9:56 AM, Glen Smith <mrglenasmith at gmail.com> wrote:

> I see that others have chimed in with some possible solutions, if I'm too
> late to the party, that's just how things go for me.
>
> http://www.adafruit.com/products/1512
>
> Adafruit has three different solenoids that might work, 2 marked as 9-24v
> and the one linked above which is listed as 9-12v. Personal experience with
> the large 9-24v one indicates that less than about 18v gives less than
> satisfactory results - especially if the magnet needs to pull against
> gravity or any other frictional or weight resistance. But with a good
> MOSFET and protection diode, these can be simply actuated by TTL levels.
>
> Hope this helps.
> Glen
>
>
> On Mon, Sep 23, 2013 at 6:57 PM, Lucas Rumney <lrrumney at ncsu.edu> wrote:
>
>> I am trying to make something that would achieve the following end:
>>
>> raspberry pi being able to release a weight on a string.
>>
>> My idea was that the pi could send a signal to disengage some kind of
>> clamp and release the weight, but I am not sure what kind of clamp or what
>> I should use here?
>>
>> Does anyone have any better ideas how to release a weight on a string
>> controlled by a pi?
>>
>> Thanks, I can't attend this meeting because of my courseload, but I still
>> want to participate in general discussions.
>>
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>>
>>
>
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