External hardware is not strictly within the scope of Beltower software, but a few hints are offered here.

Proximity detector sensors, which respond to changes in the resonance of a tuned circuit, are amongst the most reliable for tower bells, but seem no longer to be available.   This is based on a design by Aidan Hedley (originally from Maplin) which includes a timer, providing a stable signal of preset duration.

Actuators

For best results, the actuator coils and sensor coils should be identical, as shown in the diagram below.
They consist of 30 turns of wire, approx 150mm per turn, which can be wound around a 50mm tube and finally held together with sticky tape or cotton, and finished with a capacitor soldered across the ends.   They can then be flattened to an eliptical or rectangular shape, to fit on the bell wheel.

Sensors

Wiring Diagram:

  Build the components on veroboard strip board or a printed curcuit board.

Additional Components:

8 pin Dual-In-Line sockets - 2 No, 4.4m 28swg or 32swg enamelled copper wire per coil, LED is 5mm red, ABS box 80x60x40 (eg. MB1) and Veroboard strip board 3962 (might do 8 sensors).

The components are likely to cost about £25 per sensor, but, with P&P costing about £4 a time, mistakes can add considerably to the cost.

Assembly:

Mount the assembled components in a small plastic box, with the coil at the end, as shown.

Sensitivity adjustment:

Adjust VR1, which controls the sensitivity, so that the LED is just on, then turn it back until it just goes off.   Now bring an activator near L1, and the LED should light.   Remove the activator and, if the LED doesn't go off, turn VR1 back a bit more.