New member here and quite new to electronics, but have dabbled before.
I'm trying to find the smallest board and guidance on best to wire up my project. I've created a 3D model which is intended for 3D printing and will be a Stargate Address cartouche. I'm going to print the 7 address chevrons in a transparent filament, which I want to illuminate.
I'm looking to put a strip of 15 LEDs in the back panel with a small on/off push button switch on the back to just turn the lights on or off, nothing else. I would like to power this with batteries, if possible, but will be open to a cable if it needs the power.
I'm wondering if someone can help point me in the right direction in which is the smallest arduino board and if it can be powered by a coin cell, or if I need direct power.
Welcome Tim,
If you just need to turn some LEDs on and off with a battery as power you just need a switch, nothing else. You probably need resistors to limit the current to the LEDs. You certainly don't need an Arduino.
Probably not. It depends how much current is needed to illuminate each led to the level of brightness you require for your model.
Also the colour of the LEDs is important. White LEDs often need a voltage of around 3.0~3.5V to light, and you need more voltage than that for your batteries because you also need those current limiting resistors, and they will also drop some voltage.
3xAAA or 3xAA non-rechargeable or 4xAAA or 4xAA NiMH or maybe a li-po battery would be suitable. A 5V PSU such as an inexpensive phone charger would also be suitable.
The processor board doesn't need much current, but you'll need quite a bit for the LEDs anyway, so as @PaulRB recommends for power.
I like using Lipo packs, a 2s pack (7.4 volt nominal) can be had in a bewildering variety of sizes (capacity and physical). A step down regulator can give you solid 5 volts. A solid state switch can turn the whole thing nearly completely off and can be arranged to be manual turn on and programmed or manual turn off.
pololu also have the step-down regulators, best to buy these from a reputable source and hope that paying a bit more means they are more likely to actually perform to specification.
I always assume when ppl say strip, they mean a strip of Neopixels, or other smart LEDs.
Look into it, even if all you want is on and off, there is easy build in flexibility to be gained by using a smart strip.
No extra driver transistors or MOSFETs, ability to adjustment brightness and color and infinite possibilities for easily doing something more than on/off, just with software. Which we all know is easy.
Hey gents, really appreciate the responses and ideas! Sounds like I'm better off going with a power plug in lieu of batteries.
@alto777 - Thanks for the link to the Pololu switch, would I need to use this with a small arduino?
Looking at this switch, it looks like I need a power board (arduino?) to plug the cable into and with the Arduino, I guess I could do a bit more with the lighting.
No, you can always just use regular physical on/off switch. Or plug and unplug whatever the power source you choose. The things I have running off phone chargers or other wall warts typically have no switch at all.
If you use a Lipo battery, however, it is nice to be able to monitor the charge state and turn off you device before it drains the cells past their preferred lowest voltage.
The pololu switch can handle larger currents, but it is happy not to, and when it turns off, there is minimal current from the battery - still a good idea to turn off the device through software well before the battery comes near to exhausted, and pay attention to getting the battery out and onto the charger.
