The basic idea of the electronic canon (refer to Project in the site) to increase the power applied to a solenoid can also be applied to this project. The circuit shown in Figure 1 charges a high-value capacitor with about 36 volts.
When pressing S1, the Silicon con- trolled rectificar (SCR) turns on and allows the capacitor to discharge across the coil.
The energy produced by the capacitor is very high, creating a strong pull for the coil. As in the electronic canon, the pull is enough to launch the coin a good distance. The reader can use capacitors in the range of 4,700 to 22,000 µF. The pull will also depend on the coil.
When mounting, be careful with the polarized components such as the diodes, SCRs, and electrolytic capacitors. If any of them becomes inverted, the circuit will not operate as expected.
Coils with 100 to 200 tuns of 28 or 30 AWG wire can be used. The initial current released by those coils can reach 40 amps or more. Test to find the best coil and the best capacitor to launch the coin with the desired force.
Operation:
First charge the capacitor by pressing S1, and then after releasing this switch, press S2 to trigger the SCR. The light-emitting diode (LED) will indicate when the capacitor is fully charged.
SCR - TIC106 or equivalent SCR
D1 - 1N4004 silicon rectifier diode
LED - Common LED (any color)
T1 - Transformer: primary coil rated according to the AC power line, and secondary coil rated to 12 + 12 volts (center tap [CT]), 250 to 500 mA
R1 - 150 ohm x 1-watt resistor
R2, R3 10 k x 1/8-watt resistors (brown, black, orange)
R4 - 1 k x 1/8-watt resistor (brown, black, red)
C1 - 4,700 to 22,000 µF >< 40-Volt electrolytic capacitor
X1 - Coil (see text)
S1 - On/off switch
S2, S3 Pushbutton (NO)
F1 - 500 mA fuse and holder
Power cord, printed circuit board (PCB) or terminal strip, , wires, solder, etc.
FIM DA LISTA
Catapult
Another way to launch coins is by using a catapult, as shown in Figure 2.
The number of turns for the coil and the mechanical system to launch the coin must be designed by the reader. Experiment to match the force of the solenoid with the weight of the coin to find the best performance. A super powerful catapult can be created using the capacitive discharge circuit.
