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Topic: [Help] Best way to sense and report a remote blinking light (Read 201 times) previous topic - next topic


This is my first Arduino project so I definitely need help, but I want to sense whether or not a light is flashing like it is supposed to every couple seconds and receive a text or report it to something like thingspeak if the light isn't flashing. So far I am thinking I need an Arduino UNO Rev3, an ArduinoGSMShield so I can text or update to the internet, a basic circuit and photocell to sense the light? and also maybe a solar panel to battery charger to keep the arduino powered on its own. Any suggestions, advice, or tips helps.


Do you have access to the blinking light? or you are wanting to adapt your device to existing hardware that you have no control over? if you dont have access to the light, then it sounds like you have the components that you need to start. I created a small project to sense low light in a theater room so that when you are watching a movie or have the lights off, inside the movie cabinets, it will sense the low light upon opening the door and turning on some low light leds so you can see the movies and pick another to watch..

All i used was uno, resister, LED strip and photocell.



For my project I'm using 2 mini breadboards, but only because I haven't had time to make it a more presentable setup. Intentions are to create get a small prototype board and solder all the connections on there so I can mount in a small enclosure to hide everything.

But for building and concept, work with a breadboard so you can easily make the connections and test things out before committing to permanent connections.


Thank you so much for helping. I think I am going use an
Arduino Uno R3 - https://www.adafruit.com/products/50
Male to Male Jumper Wires - https://www.adafruit.com/products/758
Half Size Breadboard - https://www.adafruit.com/products/64
Photo Transistor - https://www.adafruit.com/products/2831
And Resistors - https://www.adafruit.com/products/2784

I'm not sure how strong of a resistance I actually need so I was going to get a couple different resistors between 1k and 10k Ohms. I don't think I need a logic shifter although I'm not completely positive, especially if I plan to add a GSM Shield later. And then the photo transistor would detect light and if it was strong enough light it would go through the resistor. Is there anything else I am missing or might need? Also thank you for helping me with my first project.


on the photocell side of things, I'm using what I had, a 10k 1/4 5% resistor.

If you haven't already made the purchases, take a look around for better pricing

Places I buy from are


Depending on how soon you want things.. mouser is pretty cheap and quick on delivery.
Breadboards you can get sets of boards for same price as one on ebay
Digikey is pretty close to mouser on prices, shipping little more
Adafruit I get when I cant find the items at any of the other places..

Check out mouser for the parts/components before you order, may save you some money..
the uno, unless you are stuck on getting Arduino brand board, you can get comparable board from here for $5.99

Everytime I go to this store (local to us here) I pick up a few boards just to have, even the mega is cheap $9.99


I'm planning on adding an ADAfruit FONA eventually so I can send texts off of it. Will the Inland Uno still be compatable? and are you sure the inland won't have any issues? Also thank you I will look around for some better pricing. Also for reference,

I want the resistor strong enough to not be set off by say, moonlight at night, will a 10k resistor be strong enough?


I have not had any implementation issues with the inland brand, others may be able to chime in, but i would think you will be fine..

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