Guidance on connecting multiple IR break beam sensor to Arduino Uno

Hello all,

I am trying to connect multiple IR break beam sensor to Arduino Uno , read the sensor values and process the information. I will be powering the Arduino UNO using USB ( from laptop ).

Apart from sensors , i will be using an HC06 bluetooth module and one LED. IR break beam sensor that will be used is the 5mm version from Adafruit - https://learn.adafruit.com/ir-breakbeam-sensors?view=all

I could successfully get the readings from 1 pair of sensor and now i wish to form an array of more than one IR sensors and the read the output from individual sensors.

  1. Considering the above setup, what will the maximum current drawn from the 5V pin of Arduino.?

I did some search on the internet and found out that upto ~400 MA can be drawn from the 5V pin that is powered by USB.

If that's the case how many more sensors can i accommodate.?

Adafruit link says the emitter draws a current of ~20 MA..so can i form an array of say 4 sensors?

4 times 20 mA is a lot less than 400 mA so you should have no problem.

There is no reason why you have to power the sensors from the Arduino 5v pin. You could use a separate 5v power supply if you need a lot of current.

If you need more help please post your code and a link to the datasheet for your sensors.

...R

Robin2:
4 times 20 mA is a lot less than 400 mA so you should have no problem.

There is no reason why you have to power the sensors from the Arduino 5v pin. You could use a separate 5v power supply if you need a lot of current.

If you need more help please post your code and a link to the datasheet for your sensors.

…R

Thanks Robin. I could successfully connect 3 pairs of sensors using the 5V pin and read the sensor values…

Here is the link to data sheet - https://cdn-shop.adafruit.com/product-files/2167/C2916.pdf . Its in non-english… but below is what the Adafruit website says:

Sensing Distance: Approx 25cm / 10"
Power Voltage: 3.3 - 5.5VDC
Emitter Current Draw: 10mA @ 3.3V, 20mA @ 5V
Output Current Capability of receiver: 100mA sink
Transmitter/Receiver LED Angle: 10°
Response Time: <2 ms
Dimensions: 20mm x 10mm x 8mm / 0.8" x 0.4" x 0.3"
Cable Length: 234mm / 9.2"
Weight (of each half): ~3g

If i were to use an external power supply, I suppose i need to connect to the power jack of the Arduino.
How would i read the serial communication readings…i.e., sensor readings in that case?

Thanks
Abhay

abhaybhegde: If i were to use an external power supply, I suppose i need to connect to the power jack of the Arduino.

I only suggested an external power supply in case you need to connect a large number of sensors. With just 3 there should be no need for it. Also I had in mind that the external power supply would power the sensors separately from the Arduino - just make sure the sensor GND is connected to the Arduino GND.

...R

Robin2: I only suggested an external power supply in case you need to connect a large number of sensors. With just 3 there should be no need for it. Also I had in mind that the external power supply would power the sensors separately from the Arduino - just make sure the sensor GND is connected to the Arduino GND.

...R

Ok, for now let me stick to USB..

Considering the below specs of the sensors

Power Voltage: 3.3 - 5.5VDC Emitter Current Draw: 10mA @ 3.3V, 20mA @ 5V Output Current Capability of receiver: 100mA sink

Can i be safe with say connecting 6 sensors, 1 LED, 1 HC06 Bluetooth module ? Just wanted to be sure, last thing i want is a broken Arduino :)

Your six sensors will draw about 120 mA so I don't think there will be any problem.

I presume the outputs of the sensors are only triggering Arduino I/O pins set as INPUT - they take very little current.

How has the solution grown from "an array of say 4 sensors" to 6 ? :)

...R

Depends also on the input voltage: if powered by a 12V source the regulator has to drop 7V, with a total current of some 150-180 mA that's well over 1W of power to dissipate. So don't touch the Arduino when operating it - the regulator will get really hot, until it's so hot it just switches itself off. If powered at 7V or so, it'll be fine. Or 5V to the Vcc pin, then the regulator isn't used.