LED Indicator Lights for Prototyping - Using Scraps




Introduction: LED Indicator Lights for Prototyping - Using Scraps

About: Aspiring design engineer from Imperial College London from Hong Kong. Museum lover. Interested in STEM communication, experience design, and making things. Chair of Imperial College Artisans Workshop. Secretar…

I made this for a university project, in which I needed to quickly wire up some LEDs to draw attention to specific parts of a prototype I was working on. Like the gif above.

I managed to accomplish this using a few bits and bobs lying around, and was able to spend exactly 0 dollars in creating this very neat and incredibly useful - albeit slightly crude - tool in prototyping.

Step 1: Supplies

Here's a list of what I used:


- Rotary switch (I got mine from a totaled 6-speed hand mixer from a previous project)

- LED strips (I had a short strip spare from a previous project that I couldn't really use anywhere else because it was too short, but was perfect for making indicator lights)

- 11.1V lithium ion battery (with inbuilt protection circuit) and connectors (I borrowed this from the EEE department in my university)

- Wire


- Solder

- Soldering iron

- Hot glue gun

- Drill

- Masking tape

Feel free to substitute with anything similar.

Step 2: The Circuit

This is what needs to connect to what:

- Positive terminal of power supply to knob of switch.

- Output of switch to positive terminal of LED. (6 outputs for 6 LEDs.)

- Negative terminals of LEDs to negative terminal of power supply.

The switch completes the circuit for each LED independently via the mechanical action of turning the switch, which allows the metallic connector on the switch to contact each output individually.

Step 3: Preparing the Supplies

Before I could wire everything up, there was some preparation to be done.

- I had to clean up the components, by desoldering whatever they were connected to before.

- I had to drill holes in the prototype build for the wires to go through.

- I had to measure and cut the appropriate lengths of wires, by using a piece of string to mimic the wire.

Step 4: Wiring Up

Then it's just a matter of soldering everything together.

Above is a series of tutorials on how to solder, courtesy of paceworldwide.

Be careful here though, as depending on the sizes of your components and the drilled holes, you may need to work at the prototype, and arrange all the wires before soldering. Otherwise the components won't be able to pass through the holes. Of course, you could also choose to forgo the holes, and just let the wire run around whatever obstacle in its way. In which case you need to plan for longer wires, and a way to keep them hidden from view, or at least tidy and unobtrusive.

For this step, I used masking tape to help keep the wires tidy and untangled, and hot glue was also useful to hold weak solder joints together, just as a quick solution to keep things stuck together and maintain a good connection.

Step 5: Testing and Tidying Up

Finally, I gave my circuit a few tries, checked that everything works, and installed it in my prototype!

I again used masking tape to keep everything tidy and hide the wires from view. The switch was placed in an easily accessible but unobtrusive place, while the battery was squirreled away in a corner.

Then I proudly presented my prototype and was able to highlight all those nifty features my team have worked so hard on!

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5 years ago

Good idea and implementation, much more effective than a stick or laser pointer too. ☺


Reply 5 years ago

Thank you!