Integrating simple electronics in to 3d pen made stuff.

[Vanity Smurf]

I have been playing around making thing with a 3d pen, mostly turning them in to key fobs. the idea struck me that maybe i could put LEDs in them, in the eyes of the Pikachus for example but i know enough about electronics to know that beyond Science kit type toys i know nothing and know even less about what i would need to use to make the idea work. There is conductive PLA filament that i have seen used in simple circuits.

What adavice do you guys have as to what i should do or where i should go to find out what i need to know?

[Vanity Smurf]

other stuff i made.

[Zero999]

Start with LEDs first.

All that's needed is a battery, a resistor and the LEDs. There doesn't appear to be much space for the battery. Small coin cells could be used, in which case you might be able to avoid the need for a resistor, as the batteries will have a high enough resistance to limit the current to the correct level for the LEDs.

[CJay]

Start with LEDs first.

All that's needed is a battery, a resistor and the LEDs. There doesn't appear to be much space for the battery. Small coin cells could be used, in which case you might be able to avoid the need for a resistor, as the batteries will have a high enough resistance to limit the current to the correct level for the LEDs.

And the conductive PLA is about 30 ohms per CM so that'd help as well.

There's a nice and simple LED tutorial over on Instructables:

https://www.instructables.com/id/LEDs-for-Beginners/

The OP does need to be aware that coin cell batteries can be very dangerous if swallowed and the things being printed are likely to be attractive to kids so it needs to be thought about.

[Vanity Smurf]

if i understand correctly, i need :-
 a soldering iron
 lead free solder
 button cells
 metal clips for the button cells
 LEDs
 Wires or the conductive filament
 and maybe resistors (no idea what ratings on them though)


sorry i have dyspraxia and a little slow on the uptake at times.

[Zero999]

Lead free solder is rubbish. Use the proper leaded variety, if you can get hold of it. Metallic lead is inert and not harmful, because it's not easily absorbed by the body. Just don't eat it and you'll be fine, but even if a small amount is eaten, it won't do any harm, as it'll pass trough the digestive system and go down the toilet!

[Brumby]

I will reinforce the warning about button batteries - and small things in general.  Safety cannot be overstated, especially when it comes to children.  This is a particularly significant consideration if these pieces are going to be taken outside your supervision.

I will add one comment .... How do you propose switching on and off?  If permanently connected, the button battery won't last very long.  Another mechanical consideration: Changing batteries.

[Vanity Smurf]

for the on switch i was thinking squeeze or a little button, and for the battery safety thing i was thinking the battery being none replaceable maybe.

[Zero999]

for the on switch i was thinking squeeze or a little button, and for the battery safety thing i was thinking the battery being none replaceable maybe.

That's a sensible suggestion but don't solder directly to the battery. It will explode!

Another possibility is makde the battery replaceable, but only accessible by undoing a screw.

[CJay]

for the on switch i was thinking squeeze or a little button, and for the battery safety thing i was thinking the battery being none replaceable maybe.

There were or may still be, some *really* simple LED keychain lights with have one lead of the LED held in flexible plastic button, when you press the button the lead is pushed down onto a terminal of the battery.

[Vanity Smurf]

would tearing down and using the internals from things like https://www.amazon.co.uk/Bright-White-Keyring-Torch-Black/dp/B0050HPACG/ref=sr_1_8?ie=UTF8&qid=1535045262&sr=8-8&keywords=led+keyring  work.

[CJay]

That's pretty much the exact type of thing I mentioned, if you get one you'll find there's nothing in there but a coin cell and the LED.