I'm trying to build something that looks a little older, so using LEDs doesn't really work well, and figured some low voltage light bulbs would work great. I grabbed some 2.5v bulbs and little mounts for them. Lighting them with 2.5-5v worked great (a bit too bright at 5v, which was understandable).
My problem is getting them to light up with the arduino (Uno, if it matters). I have a basic sketch (starting with the "blink" example in the core example set) and it doesn't light up. I put in an LED and it lights up great. I put the bulb into either the 3.3v or 5v pin directly and the bulb comes up, but not at any of the regular pins (I've tried both PWM and regular pins,with both analogWrite and digitalWrite).
Any thoughts? I assume I'm missing a simple-but-clever piece to this, but it's eluding me and there isn't much on driving small light bulbs like this from the searching I've done (or the volume on LEDs and driving full size light bulbs has buried it).
To light up a 2.5 Volts bulb using Arduino you will need following things.
A power Transistor(like 2N3055 or BD series) OR a Relay
A 5V 300mA DC power supply (If not readily available then make it using a step down transformer and diodes and filtering Capacitor)
Connect GND of arduino and GND of power supply .
Connect the power transistor base to arduino digital out pin using a appropriate series resistor.
Emitter to GND and collector to one pin of the bulb and other pin goes to DC supply +ve pin.
If bulb burns too bright... put a series resistor of say 100R or so.
OR
You can drive bulbd using relays(If you are OK with TIC TOC sound )
Let me know if that's clear to you.
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