Active InfraRed driveway alarm interfacing with Arduino

I am thinking about ordering two pairs of these:

But before I do I was hoping to get some project guidance on here, as I don’t quite understand their wiring diagram and am unfamiliar with wireless transmitter/receivers for use with Arduino.

It says “Radio sending out”, which I assume means it relays “1A 36V max” to an external radio transmitter. The reason I want two pairs is so that I can log arrivals and departures and ultimately the number of vehicles present with Arduino. Is it possible to therefore send one of two signals (arrival or departure) via one e.g. a nRF24L01 transmitter/receiver pair?

What kind of power regulating module can I use for this setup?

Any guidance/information would be greatly appreciated.

its straight forward, but could be better drawn.

You connect your power to the four terminal and from there you also connect power to the transmitter (2 terminal), making sure that voltage and polarity are correct.

Then you set the jumpers to normally open or normally closed as suits your application.

If you select normally open : when the beam is broken the relay is closed (COM is shorted to OUT)

So if you connect 5v from your Arduino to COM and OUT to pin2, you can then use attachinterrupt on pin 2 to detect every time the beam is broken. (However, read up on avoiding bounce on switches to avoid counting a single break more than once)

For anyone interested in IR protocols – we have just launched a Crowdfunding campaign on IndieGoGo for AnalysIR – IR Decoder & Analyzer (Arduino & Raspberry Pi). Currently we support 17 IR protocols and are looking for more to add as part of the campaign. Suggestions Welcome!

You can find out more about the Campaign on or Screenshot via

Ah ok that makes more sense. Since I have two pairs of sensors, what would be the most effective way to power them? I figure I'll need at least two power supplies, one for the transmitter and one for the receiver end of the sensors

Also I am planning on using a pair of NRF24L01 transcievers, one to connect to the sensors and one to connect to the arduino. So one of the NRF24L01 will have to be powered (preferrably by the sensors power supply) as well. This also means directly connecting the arduino to either of the IR sensors is not an option.

Is there anyway to consolidate the seperate power requirements with limited experience and something I can put together on a breadboard? Without needing 5 seperate power supplies (4 for the sensors and one for one of the NRF24L01 pair)? I guess I could settle for having each of the emitter/receiver pairs powered in parallel since they use the same voltage and a seperate power supply for the NRF24L01, for a total of 3 power supplies (I cant run a cable between emitter/receiver).

I figure I can either use two disposable 6V batteries, a solar-rechargable battery of some kind, or a 12v car battery (which I can charge).

Do I need to limit the current to these devices? Or will they automatically draw the correct amount as long as the voltage is correct?

Finally, regarding the messages sent by the NRF24L01, what would be the best way? I need a way of distinguishing which sensor is activated first so that I can determine which way the vehicle is travelling and hence arriving/departing.

The only way I can think of is to have one sensor pair HIGH when crossed, and the other pair LOW when crossed. Then write the output to a byte somehow so one direction would be 0000 0001 (LOW then HIGH) or 0000 0010 (HIGH then LOW). Although I admit I have no idea how to do this and I haven't yet researched the NRF24L01 transcievers. But then the LOW-active sensor would use a disproportional amount of power to the HIGH-active sensor, or is this negligible given that they would be sharing a power supply in parallel?

So is there a way I can use two NRF24L01 modules to setup the wireless sensors? Or does there need to be an arduino at each end?