Impulse pendulum testing with a PIC12f675 micro-controller. The same type setup might be used for a battery powered clock at some stage, if I get around to designing one. 

To the right is the program written for the chip, and a circuit diagram is below the video.

;Chip Settings
#chip 12f675,4
#config MCLR=OFF, WDT=OFF

;Defines (Constants)
#define adc bits = 10
#define led gpio.0
#define led2 gpio.4
#define pb gpio.1
#define pb2 gpio.2
#define coil gpio.5

ansel = 0
dir gpio.0 out
dir gpio.1 in
dir gpio.2 in
dir gpio.4 out
dir gpio.5 out
set coil on
for f1 = 1 to 10
set led2 on
wait 50 ms
set led2 off
wait 50 ms
next f1
b1 = 1
start:
val = readad (an2)
if val < 2 then
goto start
end if
coilon:
set led on
set coil off
wait 5 ms
set led off
set coil on
goto start