3. AC mains alarm

Status: OK

This device makes alarm sound periodically when the near cable has AC signal. In debug mode it can be used as AC mains detector.

3.1. Pins

board pin	AVR pin	Arduino pin
in	PC3	A3
speaker	PB1	D9
debug in	PC0	A0
debug LED	PC5	A5

3.2. Schematic

3.3. Board

Normal, bottom mirrored, wires only:

3.4. Partlist

part	value	position
C3	100n	(1.45 0.4)
D1	1N4148DO35-10	(1.2 1)
IC2	MEGA8-P	(1.45 0.65)
JP1	POWER	(1.45 0)
JP2	IN	(1.05 1.7)
JP3	DEBUG	(1.35 1.2)
JP4	SPEAKER	(2.15 1.7)
LED1	DEBUG	(0.75 1.2)
R1	10k	(1.1 0.3)
R2	100	(1.95 1.1)
R3	1k	(1.05 1.4)
SV1		(1.65 1.7)

3.5. 3D view

3.5.1. Front

3.5.2. Right side

3.5.3. Left side

3.5.4. Bottom

3.6. Sources

Based on this design: http://www.edn.com/article/511304-Detect_live_ac_mains_lines.php