From a3cfb0b01da791ae91bcdc414eac9f0f7b6077c3 Mon Sep 17 00:00:00 2001
From: Ben Harris
ClunkPi is essentially a switchable current source. It - provides a current of 250 mA ±10% into a resistance of up - to 12 Ω. It is switched by GPIO line 17 from the Pi. It - is powered by the Pi's 5 V line, from which it needs - 250 mA.
+ provides a current of 250 mA ±10% into a resistance of up + to 12 Ω. It is switched by GPIO line 17 from the Pi. It + is powered by the Pi's 5 V line, from which it needs + 250 mA.In theory, it should be possible to run ClunkPi off a higher - voltage to drive multiple clocks, up to the 50 V limit of + voltage to drive multiple clocks, up to the 50 V limit of the drive transistor.
I designed ClunkPi using @@ -33,7 +33,7 @@
The circuit is a simple current source controlled by a shunt voltage regulator. U1 and R2 control the base current in Q1 to - achieve 1.24 V across R1. D1 suppresses any voltage spike + achieve 1.24Â V across R1. D1 suppresses any voltage spike caused by the inductance of the clock coil.
Plug the board into a Raspberry Pi with the square solder pad -- 2.30.2