Tan Timer Circuit Diagram

Description 

This timer was designed for people wanting to get tanned but at the same time wishing to avoid an excessive exposure to sunlight. A Rotary Switch sets the timer according to six classified Photo-types . A Photo resistor extends the preset time value according to sunlight brightness . When preset time ends, the beeper emits an intermittent signal and, to stop it, a complete switch-off of the circuit via SW2 is necessary.

Circuit diagram:

Parts:

• R1 = 47K - 1/4W Resistor
• R2 = 1M - 1/4W Resistor
• R3 = 120K - 1/4W Resistors
• R4 = Photo resistor (any type)
• R5 = 120K - 1/4W Resistors
• C1 = 10µF - 25V Electrolytic Capacitors
• C2 = 220nF - 63V Polyester Capacitor
• C3 = 10µF - 25V Electrolytic Capacitors
• D1 = 1N4148 - 75V 150mA Diodes
• D2 = 1N4148 - 75V 150mA Diodes
• Q1 = BC337 - 45V 800mA NPN Transistor
• B1 = 3V Battery (two 1.5V AA or AAA cells in series)
• IC1 = 4060 - 14 stage ripple counter and oscillator IC
• IC2 = 4017 - Decade counter with 10 decoded outputs IC
• SW1 = 2 poles 6 ways Rotary Switch (see notes)
• SW2 = SPST Slider Switch
• BZ1 = Piezo sounder (incorporating 3KHz oscillator)

Notes:

• Needing only one time set suitable for your own skin type, the rotary switch can be replaced by hard-wired links.
• A DIP-Switch can be used in place of the rotary type. Please pay attention to use only one switch at a time when the device is off, or the ICs could be damaged.

circuit from http://www.extremecircuits.net/2009/12/tan-timer-circuit-diagram.html