Selfie Ring Light Tutorial #7: Electronics

This is Tutorial #7 in the Selfie Ring Light Tutorial series.
This tutorial can be completed independently of Tutorials #1 to #6.

In this tutorial, we assemble and test the electronic components in your project box.
On completing these steps, you will have Bright Blinky Lights! …but you’ll still need a case for them.

The Selfie Ring Light is designed so the electronics can be built and tested first.
(The next tutorial covers the final install and assembly)

This is the electrical view of what we’re building; the Schematic or Wiring Diagram

We’ll refer back to it several times.


One tool we use today is the Soldering Iron.

Soldering (which Americans pronounce ‘soddering’ for some reason) is a process where:
Two hot pieces of metal are jointed together with a molten filler metal, heated by an iron.


Did you see that word above? HOT.
The soldering iron gets very hot.

Anything that the soldering iron touches gets hot.
When you solder a joint, it could stay hot for the next 10-30 seconds.

If you solder a short wire, the other end will get hot.
Wires conduct electricity very well. They conduct heat well, too!

If you burn yourself, you will learn quickly and painfully what not to do.
We’d rather you didn’t burn yourself, but if you do get burned let a Tech know.

The Basic Steps to Soldering:

  1. Clean the iron by melting a little bit of solder onto it, and wiping it off on the sponge.
  2. Heat up the joint (the wires, the circuit board pad, etc) by holding the hot iron against them.
  3. Introduce a little bit of solder into the space between the joint.
  4. Keep the Soldering Iron in place until all the solder has flowed into the joint.

Easy right?

Well, here are the mistakes that everybody makes:
(and you will too! Don’t worry – it takes a while to get it right)

The solder won’t flow! It won’t stick to the joint / the wire / the pin!
The metal isn’t hot enough yet!
Heat the joint up first, then add solder.
Do not just keep adding solder…

The solder is touching the next joint!
Too much solder! You only need a small amount.
Ask a Tech to show you how to get rid of the excess solder.
Do not switch on the power to your circuit, there may be an electrical short.

I did all that, and heated it up for ages, and it’s still not sticking!
Okay, solder actually has a special extra ingredient called ‘flux’.
It helps the solder stick the joint together, but it boils away when the solder is melted.
If you had a lot of molten solder sitting on the iron there could be no flux left.
1. Clean the iron and try again.
2. Maybe add a little bit more solder.

Step 1: Parts Check

In your project box, you should find;

  • 3x  AAA batteries. Powah! 
  • 1x  Battery holder. With on/off slide switch and red/black wires
  • 1x  Digispark control board. Already programmed with SRL brains
  • 1x  Red tactile switch. Click. Click clickclickclickclickclick
  • 1x  24-LED ring light. Oooo….
  • 4x M3 x 12 flat head phillips screws. Sound familiar?
  • Some red, black, and white wires.

Check that your box has all these items. Let a Tech know if anything is missing.

If it’s all there, on to Step 2…

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