Extreme Business Cards

Step 2 The Torch Parts

Here you can see the parts - a PCB, coin cell (CR2032), a coin cell holder, a 3mm LED (any colour should be fine), a PCB-mount switch, and a resistor. A complete parts list for both projects is available as a link below if you want to find where to source some of these components. The value of the resistor is usually around 68 ohm for most colour LEDs. It is a surface mount device, so is very small - the exact type you get isn't critical - I used a "1206" package as it is easier to solder, but 0805 or 0603 packages can be soldered on as well if you have good eyesight! If you are using a blue or white LED, they are meant to be too high-voltage to really use with a single coin cell, but if you use a bright one, you can just remove the resistor completely (short with a blob of solder or use a "0 ohm resistor") and the light, although not full intensity, should be quite bright (see the image of it turned on a couple of pages later). You want to get the highest intensity 3mm LED you can find - there are some great deals on ebay, which is usually the cheapest place to find these.

If you want more information on how both of these projects work technically, including how to properly choose resistor values, see the extra technical information sheet that I have posted below as well. I could make up a batch of 100 of these for under $1 each, including PCB -not bad for some extreme marketing, but you could probably even half this price if you were serious about making these in quantity and could do without the battery holder (see the notes in the parts list about welding batteries).

Comments

[alfra]

I would like to try it.