Forum Diagram: lamp

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Sunday, August 17, 2014

Led or Lamp Flasher Circuit

This schema was designed to provide that continuous light lamps already wired into a schema, become flashing. Simply insert the schema between existing lamp and negative supply. Especially suited for car or panel pilot lights, this device can drive lamps up to 10W.

Parts:

R1 = 6.8K
R2 = 270K
R3 = 220K
D1 = 1N4002
C1 = 220uF-25V
C2 = 10uF-25V
Q1 = BC557
Q2 = BD139
B1 = Any type in the range 3-24V
B1 = Suited to the lamp adopted
LP1 = Filament Lamp 10W-3V to 24V
SW1 = On-Off Switch

Notes:

* Break lamp to negative supply connection, and then insert the schema between existing lamp connection and negative supply (respecting polarities!).
* C1 value can be varied from 100 to 1000µF or higher, in order to change flashing frequency.
* Although rather oversized, this schema can also drive any LED, providing a suitable resistor is fitted in series with the light emitting device.
* The resistor should lie in the 47R to 2K2 range, depending on supply voltage.

RGB Solar Lamp

This deluxe solar-powered light uses a battery and solar cells salvaged from a solar lamp with a four-cell battery (4.8 V nominal terminal voltage).

RGB Solar Lamp Circuit Diagram

The schema can operate from any DC voltage around this value and its current consumption, at 20 mA, is low. This means that the battery can give up to ﬁve days of operation. The schema consists of an Atmel ATtiny microcontroller which drives a red, a green and a blue LED directly from three port pins. Series resistors are of course included to limit the LED current. The microcontroller drives the LEDs in sequence to produce an RGB running light effect. The microcontroller is also responsible for ensuring that the light automatically switches on when it gets dark and off when it is light. The light sensor is made from one of the solar cells from a bro-ken solar lamp (it is more common for the battery to fail rather than the solar cells).

The power output of this cell is not important, as the microcontroller only measures its output voltage using its internal A/D converter connected to pin PB4. The project is ideal for beginners, as a ready-programmed microcontroller is avail-able from the Elektor Shop (order code 100581-41).