This light activated kit is also available as a temperature activated project kit. The output of theis board can be used to control other electronic circuits, turning them on automatically when it goes light or dark.
The board has space for an LED with current limit resistor (both available separately) which will light when the output turns on.
The Darlington pair transistor configuration allows an output current of up to half an amp to be controlled. Operating voltage 3V to 12V (lower voltages allow for better adjustment of the switching point).
- This Light Switch Kit detects the brightness of its surroundings using an LDR.
- The kit acts as an automated on/off switch (light dependable) for many devices.
- 1 x 47KΩ Potentiometer.
- 2 x BC337 NPN Transistors.
- 1 x Miniature LDR (Light Dependent Resistor).
- 1 x 220Ω Resistor.
- 1 x Light Activated Switch PCB
Possible applications include:
- Garden light that switches on automatically at night.
- Draw alarm, which sounds when a dark draw is opened.
- Line following robot (using 2 light activated boards).
- PCB Length: 53mm.
- PCB Width: 25.5mm.
- This kit requires soldering.
Teachers can order a sample of this kit (one per school) here. You will need to select the kit from a list of all the sample kits; the stock code for this kit is 2112.
Note: this service is only offered to schools for evaluation purposes only.
This kit is designed and manufactured in the UK by Kitronik.
- PCB Length: 53mm.
- PCB Width: 25.5mm.
- PCB Component Count: 5.
- Voltage Nominal: 3V.
- Voltage Range: 3V - 12V.
- Standby Current: 0.12mA.
Gary Haddon from the Moseley School in Birmingham sent us these examples of Year 8 students' timed night light made from our Light Activated Switch Kits. The night light is made from a vacuum formed base with a laser-cut polypropylene shade. Each pupil designs their own shade using CAD so that each night light is unique. He also sent us the photos of the giant model he made, which the teachers use a teaching aid, we think it's a great idea!
An example of a Garden Night Light.
Miniature Automatically Stopping Boat designed by students at Fernwood Comprehensive School.
A guide to understanding how a Potential Divider / Voltage Divider works. What is a Potential Divider / Voltage Divider? This is a simple circuit which takes advantage of the way voltages drop across resistors in series.
Learn how to make a Line Following Buggy (using 2 Light Activated Boards) in our easy to follow tutorial.
Learn how to make a Drawer Alarm, which sounds when a dark draw is opened, in our easy to follow tutorial.
Learn how to make a Garden Lamp, that switches on automatically at night, in our easy to follow tutorial.
A guide to understanding how an LDR works. An LDR is a component that has a (variable) resistance that changes with the light intensity that falls upon it. This allows them to be used in light sensing circuits.
i need a switch that will switch on a battery charger whenthe LED denoting it has charge in it goes out, but will not switch off again as another LED wil light to say it is charging....it will need to be a relay to switch 240V standard three pin switched house socket ON. any suggestions greatly appreciated, thanks.
Posted byon Tuesday, 18 October 2016
Unfortunately we don't do any kits which would perform that task.
Would this circuit act as a switch for a DC motor?
Posted byon Wednesday, 31 August 2016
Hi Paul, you may be able to use this to switch the DC motor, however it depends on the specification of the motor. The light activated switch kit can output 500mA, and can be powered between 3-12V’s. You may be better using the kit to trigger a relay which is then used to power the motor.
Is the LDR water resistant? I want to use this to activate LEDs on my motorcycle when it gets dark out.
Posted byon Friday, 19 August 2016
Hi Daniel, although the LDR housing is epoxy sealed the datasheet for the product doesn’t state that it is waterproof. As such it would be recommended to encase this in a waterproof housing, ensuring that where the LDR sits that it is a clear material to allow light to pass through.
Could I use this to make a nightlight with 2 LEDs ? if so what modifications are needed ?
Posted byon Friday, 6 May 2016
You wouldn’t need to modify the board, just add components into the correct places. You would add the LED’s onto the output section of the board, and then you would put a suitability rated resistor into R3. This can be calculated on the LED product page, using the LED calculator function.
Would this circuit be able to activate a relay? I'd like to have this device activate a relay which would activate an air horn.
Posted byon Thursday, 3 March 2016
Yes you would be able to use this circuit to power a relay. The circuit can output 500mA and can run on a voltage range of 3-12V.
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