I am making a gadget using an led as a light source, a light detector about 10cm away. When an object passing between the led and the detector at night, the light will be cut off which triggers a pull-solenoid to kick off a series of mechanical actions.
Wondering if a ready-made one is available. If unable get it off the shelf, I need help to create the electronics to perform the above action. My electronic knowledge is very basic, so I like it as simple to make as possible.
Just in case a colour of the light is not suitable, please recommend more than one type of leds/detector combinations. Thank you.
Just to clarify, are you wanting a ready made device that will detect the light from an already existing LED?
OR
Are you wanting any device that uses light as a trip wire?
This technology sounds similar to laser.
Similar to your LED trip wire, we are emitting light and listening for returned luminosity.
Have a look at this article by @Michael. You could check sharp sudden dips in the range which would be just like your trip wire.
I can get a set the sensor and a 5V small pull-solenoid, could you please help by providing:
a list of all the parts needed to make the device planned (when the light is cut off, that triggers the pull solenoid). Please include price for each item.
Unfortunately we dont have the capacity to go deep into any single project on the forum, though there are excellent guides for each of the parts and I’ll attach those.
(Pricing will also change, so I’ll leave links to each of the products so you can order them)
Hi Liam,
With the 4 items you suggested, put them together, it is possible to make the device I have in mind - triggering the solenoid when an object passing the sensor setup. If that works, I shall put an order in. Please advise. Thanks.
If you wire the power connection to the solenoid via the relay’s output then you can have the solenoid powered when the sensor is triggered.
So the signal in effect works as below:
Hi Trent,
Thank you for the advice over the phone yesterday. The AC supply is not quite suitable for my application. Instead of power source recommended by Liam, I would like to use either 6V or 9V battery. As such, I will need parts to hold the battery and connection to power the device. Would those parts recommended by Liam able to handle 6V supply? If using 6V batteries, will the batteries last a few days? Please advise. Thanks.
Having the project battery powered is possible but you’ll need to make some adjustments.
All of the parts Liam has suggested can’t handle much more than 5V, so your options are to either find higher voltage versions of each part, or to add a regulator to convert the voltage of your battery pack down to 5V so that the existing parts can be used.
A regulator like this will be able to take the voltage from your battery pack and convert it to stable 5V output for the rest of your devices, however soldering will be required to assemble and connect it to the circuit.
Relay - controls the higher power solenoid, since the IR sensor is open collector you can wire it directly to the input pin of the relay
Solenoid - I’ve used this small 5V one with great success
S7V7F5
Battery holder with connection to the circuit. Please recommend the appropriate one.
Do I have to get a small board to hold all the parts together? If so what would you recommend?
I have access to a soldering kit, so that is not an issue.
