Instructables

Step 7: Build: Install the other electronics

Picture of Build: Install the other electronics
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The three pins on the lower right of the Forebrain board is where you can get the GND and 5V supply from, and the firmware is set up to use Port 2, Pin 11 to drive the transistor.  See the circuit diagram attached.

Careful of the polarity of the capacitor, and the pinout of the transistor!

Solder the other components in based on the circuit diagram.  Make sure the bell does not touch any of the components when it is replaced.  Bend the pins and install components horizontally if necessary
 
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ghurse3 years ago
to protect the USB source, May I recommend a Limiting resistor on the 5V line to the transistor (and Main Electro). The larger this Capacitor the greater the turn on "in Rush" or charge current will be.. this could be as bad as the firing of the solenoid . with a little redesign you could have a sizeable storage for the solenoid that is more isolated from the USB but still have the circuit USB powered..
imbignate3 years ago
The capacitor in your diagram is 470 micro farads, yet your initial BoM listed a 2200 uF capacitor. Which is correct?
meseta (author)  imbignate3 years ago
I suggested using at least 470uF, but preferably larger, the one I ended up using is 2200uF.