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This light-activated kit is also available as a temperature-activated project kit. The output of this 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 a 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).

Note:

  • This kit requires soldering.

Features:

  • This Light Switch Kit detects the brightness of its surroundings using a Phototransistor.
  • The kit acts as an automated on/off switch (light dependable) for many devices.

Contents:

Possible applications include:

  • Garden light that switches on automatically at night.
  • Drawer alarm, which sounds when a dark drawer is opened.
  • Line following robot (using 2 light-activated boards).

Dimensions:

  • PCB Length: 53mm.
  • PCB Width: 25.5mm.

Requires:

Resources:

    Documents & downloads

    Technical Information

    AttributeValue
    PCB Length 53mm.
    PCB Width 25.5mm.
    PCB Component Count 5.
    Voltage Nominal 3V.
    Voltage Range 3V - 12V.
    Standby Current 0.12mA.

    Related resources

    1 review for Kitronik Light Activated Switch

    1. Merryl

      good product and instructions easy to understand but NO LDR

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    Questions and answers

      Can you use the circuit board for a moisture sensor circuit? If you replace the LDR for probes.
    1. 0 votes
      Q Can you use the circuit board for a moisture sensor circuit? If you replace the LDR for probes.
      Asked by BNolan on February 12, 2020 12:00 am
      Answered by the admin Hi there, Thank you for your question, in theory yes though it might take a bit of work and technical know how depending on which sensors you use. Best Regards Cullen
    2. To use the switch output to control another device where current does not have to be limited, such as a buzzer, should R3 be a jumper wire?
    3. 0 votes
      Q To use the switch output to control another device where current does not have to be limited, suc...... Read more
      Asked by Diane Brancazio on March 8, 2019 12:00 am
      There are no answers for this question yet.
    4. Description says: The board has space for an LED with current limit resistor. What voltage LED?
    5. 0 votes
      Q Description says: The board has space for an LED with current limit resistor. What voltage LED?
      Asked by Gordon Sanderson on October 11, 2018 12:00 am
      Answered by the admin Hi Gordon, Thank you for your question, I am afraid the answer is it depends on the resistor and power supply you are using. This kit does not come with a power supply but theoretically any 5mm LED could be used provided it did not exceed 12V (as this is the limit of the darlington pair). It just comes down to the power supply used. Best Regards Cullen
    6. Will a 12 volt battery be too powerful for this switch? I want to use the switch to operate a fan in my greenhouse but the battery will be connected to a solar panel.Thanks
    7. 0 votes
      Q Will a 12 volt battery be too powerful for this switch? I want to use the switch to operate a fan...... Read more
      Asked by Anthony Morris on March 27, 2018 12:00 am
      Answered by the admin Hi Anthony, The kit can handle a maximum voltage of 12V. So as long as does it doesn't supply more than 12V it will be fine.
    8. Would a single LED light trip the switch?
    9. 0 votes
      Q Would a single LED light trip the switch?
      Asked by John on January 2, 2018 12:00 am
      Answered by the admin Hi John, It would depend greatly on the LED you are using and also the trigger point you set the kit to but technically yes you may be able to get an LED to trigger the circuit.
    10. have you got a copy of the circuit diagram for this please ?
    11. 0 votes
      Q have you got a copy of the circuit diagram for this please ?
      Asked by Jim on February 6, 2013 12:00 am
      Answered by the admin I have updated the product description on the website to include a link to the teaching material, which includes the circuit diagram.
    12. Could you please specify the LED and resistor, to be added to this light switch project, as mentioned in the description, so I can buy the lot in one go? Also, will it be obvious where these should be located on the PCB? Thanks, David.
    13. 0 votes
      Q Could you please specify the LED and resistor, to be added to this light switch project, as menti...... Read more
      Asked by David Johnston on September 25, 2012 12:00 am
      Answered by the admin You can use any LED with the board. The resistor that is used will depend on the LED you have chosen and the voltage that the board is operating off. Let's take an example of a standard red LED, where the board operates from two AA batteries: All LEDs have a forward voltage drop, for a standard LED this will be about 1.8V. The light switch circuit uses transistors in a Darlington pair configuration and this has a drop of 0.9V across it. Therefor it stands to reason that if the supply voltage is 3V and there is 1.8V dropped across the LED and 0.9V dropped across the Darlington pair then there must be 0.3V dropped across the resistor. A typical current for an LED is 10mA (or 0.01A). From Ohms law we k
      now that R = V/ I so in this case R = 0.3 / 0.01 = 30 ohms or the nearest preferred E6 value of 33 ohms. A red LED with 3 AA batteries would require a 150 or 220 ohm resistor A white LED with 3 AA batteries would require a 100 ohm resistor
    14. Hi Can I buy these in quantities of 10 already assembled? and if so how much would they be? Regards
    15. 0 votes
      Q Hi Can I buy these in quantities of 10 already assembled? and if so how much would they be? Regards
      Asked by Les Pettitt on July 18, 2012 12:00 am
      Answered by the admin Although we do some kits in a pre-assembled version this isn't one of them. The board can be configured to be activated by light or by dark and this is done by placing the components in different places. This would mean having two different version of the assembled board. So unfortunately the answer is no we don?t do them preassembled.
    16. Hi Kitronik, Can i use this kit to make a mood lamp style project and use a colour changing LED as the light output?? Thanks
    17. 0 votes
      Q Hi Kitronik, Can i use this kit to make a mood lamp style project and use a colour changing LED a...... Read more
      Asked by Simon on May 29, 2012 12:00 am
      Answered by the admin Yes it is possible to put a colour changing LED on the board, in fact because a lot of people do this we have a kit that includes the colour changing LED and a battery cage. If you have a look on the related items on the left it is the dark activated colour changing LED kit you need.
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