Powering up multiple modules of LEDs & IR receivers/emitters

[hazel77744]

Good afternoon for all!

Hi. I hope to get some advices on powering up my project. To describe my project first, I have built 4 modules which individually consists of IR pairs(a receiver, an emitter) and a transistor that acts as a switch to power up 2 LEDs when IR pairs detects presence of an object/person.

I am using Mega, and when all is connected and powered up by a laptop, it works just fine. Only when I am using external battery, 9V Sony Ultra Super, all the components except emitters work.

What I can assume is that 9V battery is not sufficient to power up all the components for LEDs are taking too much power? I am not sure how to consolidate this through calculation. And I am not sure what could be the power I need to use.

thanks for valuable advices in advance!

P.S. attached is the circuit diagram. credits to tomhv9 on Instructables page. link: http://www.instructables.com/id/Interactive-LED-Programmable-Canvas/?ALLSTEPS

However, I have removed and added resistors here and there as you can see from the amendments made in red (removed) and blue(newly added). I have made such alteration from trial and error to make it work..

[codlink]

A 9V pp3 battery isn't going to supply much current. Use AAs or even AAAs.

[Paul_B]

Ah, how we love to trash-talk "instructables" because - well they are just so absolutely awful on average. This one is certainly no exception.

You are correct - the 220 ohm resistor is a bad blunder. An equal blunder is using a 9 V supply to power single LEDs in parallel - you should be using two LEDs in series for each resistor-controlled branch and of course if you propose to battery power it, a 9 V smoke alarm battery ("PP3") is going to be useless.

And yes, the lack of current limiting resistors for the IR LEDs is yet another bad blunder.

The 1M resistor is a bit puzzling. To bias a photo-diode, it should go to +5 V and the diode anode should go to ground.