Workshop with Kids – LED Matrix with Arduino

Date: June 19, 2018

Members Attending: Kira

Project: Workshop with Kids

We are excited to tell you about our recent workshop with kids. This time we let them solder a simple 3×3 LED matrix, that can be controlled by an Arduino.

Kid soldering a cable to the matrix

The children attending the workshop already have some experience soldering, so we did not have to explain that to them again. We told them to collect 9 LEDs of their choice and 9 resistors between 100 and 300 Ohm.

To organize the LEDs in a matrix, the kids get a piece of cardboard. You can decorate this as you wish, and then poke through the LEDs. It’s an easy way to physically attach the LEDs.

The next step is to solder one resistor each to the anode (shorter leg, minus) of the LED. To test which leg is which, you can shortly (really shortly) hold the LED to an 9V block.

Now solder the end of the resistor pointing away from the LEDs together. Attach a cable about 10cm long. We will later connect this to ground. Sometimes the soldering of the kids can be quite messy. In this case make sure that everything is isolated, to prevent shorting.

Afterwards solder a cable (again about 10cm) to each cathode (longer leg, plus). Then put some solder on the other end of the cable. This makes it easier to insert it into the Arduino later.

Side note here: You should actually put a transistor between the Arduino and the LEDs as they require less current. However, everything also works without the transistor (the LEDs might be a bit weak), and it is much easier for the kids to understand what they are supposed to do.

We demonstrated the project using code that we wrote. It simply switches the pins on and off in an defined order, creating fun patterns.

This project takes about 1h30min and is suitable for children from ages 10-12. It’s great, because the circuitry is quite simple and errors and shorts are easy to find, yet it makes fun patterns, instead of boring blinking. (Though the first time they get something blinking is also exciting for the children)

Here are some thoughts about how to help the children with their projects.

First of all again, some will be much better at it than others. Just be patient with every child, and help them where necessary. However do not do the soldering etc. for them. Instead you can for example hold the wires together, while they use the soldering iron.

There will probably a lot of questions. “How do I do that again?” and “Where is this supposed to go?”. Either tell them to ask one of the other more experience kids or tell them what to do again. You’ll probably have to do this pretty often.

Encourage the children. Tell them when they did something well. Even if the soldering sometimes looks horrible. And full of shorts.

Also very important, make sure that they know how to solder, or else teach them! Soldering can be very dangerous when not done carefully!

Next week we are planning on teaching the kids a bit of coding with the Arduino. However they are quite slow at typing, so we somehow must keep frustration at a minimum.


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