| A train sound generator
with variable speed of either bell or horn sound.
It can directly drive a piezo sounder (connected between pins 15 and 16) or drive a small loudspeaker via a simple transistor amplifier. It will work from a 3 volt supply and has a standby current of 1 microamp. Two flashing LED's can be driven. SW2 and SW3 are used to increase,decrease the sound speed. |
Copyright Graham Knott 1999