[Noisebridge-discuss] Electric door strike working again. Use your Pin or key to get in.

[Martin Bogomolni]

Quick thing--

Remember that Fire Code requires that any electric door strike, or
magnetic strike, must allow someone to leave without being impeded in
a panic.  On magnetic doors, this requires a panic push bar that
physically breaks the electrical connection.   On mechanical electric
strikes, this requires that either a pushbar or simple lever be
pushed/rotated to bypass the electrical lock.

-M

On Sun, Jul 14, 2013 at 10:41 PM, Jake <jake at spaz.org> wrote:
>> The motor Scotty found takes about 300mA at 6V when free-running (so
>> for no-load 'return', maybe 500mA with load). It runs about 1 second
>> for the amount of time we need. That is about 1.8 Joules.
>> Say we can charge up a capacitor to 18 V (peak voltage of a bit more
>> than 12 V AC) and drain it down to 4 V (when this particular motor
>> just works), then we'd need about 20'000 microfarad ( 2 * 1.8 joules /
>> ((18 - 4) volt)^2 ). The calculation would be similar for other
>> motors found in the pile.
>
>
> there are at least ten 1000 microfarad capacitors rated at 50 volts in the
> pile, and i can certainly find more.  But i think the math is more
> complicated.  But since it's based on voltage squared, one 50 volt 1000 uF
> capacitor is the same energy as a 20,000 uF capacitor rated at 11.1 volts.
>
> anyway that motor sounds hella weak.  The motor i already mounted on the
> door is rated 24 volts and probably can take a good amp or two at least,
> which is a lot more power.
>
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