Blinking Lights (#1) – Arduino with Scratch for Kids

Arduino Uno Rev3

mBlock

Jumper wires (generic)

LED (generic)

Breadboard (generic)

Resistor 330 ohm

If you don’t have an Arduino kit yet, read my first post on what to buy. I am also assuming you have already installed the MakeBlock (mBlock) or similar software.We are diving into the first project for your kids… blinking lights. This project will have no sensors or inputs (yet). You will use the Arduino board and LED lights. To make multiple lights blink, you will also need resistors.<h3 >Step 1. Grab your Arduino UNO compatible board</h3>It might look like one of these:<div id="gallery"><img id="gallery" src=https://projects.arduinocontent.cc/f977632f-c9b8-4650-824b-5d48cf3f5cb7.png /><figcaption> </figcaption><img id="gallery" src=https://projects.arduinocontent.cc/37e88e4e-4d38-4607-b8c5-d29d18bb295d.png /><figcaption> </figcaption></div> <h3 >Step 2. Fire Up MakeBlock (mBlock)</h3>I will walk you through getting this set up just this first time.<figure><img src=https://projects.arduinocontent.cc/f36a2033-2ad8-47ad-8546-cc1c729c1d06.png /><figcaption> </figcaption></figure> To use mBlock, head to the tabs on the left that indicate “Devices; Sprites; Background” and select the Devices Tab. You can remove any devices there you don’t have. Click Add+… Select the Arduino UNO to download and install it in the software. Then select it again to select it and you can click the start to make it the default.<figure><img src=https://projects.arduinocontent.cc/049ca346-97b9-40a4-9684-dfb2b10f8a31.png /><figcaption> </figcaption></figure> Then click OK.Next, plug the USB cable that came with your unit to the Arduino and your computer.<blockquote >Sidenote here: You may see an LED near PIN13 on your Arduino start blinking. This is because many Arduino boards come with coding already uploaded to run a simple blinking light program. (You can just ignore the light for now.) This LED light on the board is a built in Output that you can use. We are going to use this for our first program so you don’t even have to assemble any other parts for now.</blockquote>Make sure you still have the mBlock devices tab selected and click on the “Connect” button. Select the serial port that the Arduino is connected to. I had two choices and this may take trial and error. When you have the correct one selected you will see the blue “13” LED on your board flash confirming the connection.<h3 >Step 3. Program the Arduino to blink an LED using Scratch</h3>Pause.If you have never programmed or even used scratch, you may want to stop here and familiarize yourself with the software. While we were waiting for our Arduino kit, my kids <a href="https://scratch.mit.edu/">went to the Scratch website</a> and started learning how to use it ahead of time. Even if you do the first few tutorials there you will quickly see how to program with the software. My kids made a few games, and by the time the kits arrived they had no problem diving right in.Unpause.In mBlock, using drag and drop, use an event to start the program when the Arduino starts. Add to that to set the digital pin #13 to turn on and off using delays to control the flashing. Here is an example:<figure><img src=https://projects.arduinocontent.cc/08bdfc46-e43e-4794-8442-a0292d29987e.png /><figcaption> </figcaption></figure> Then on the left click the “Upload” button to send your code to the Arduino and the Arduino will then start running the code. This should cause the LED on the board near pin 13 start flashing on and off. This is because we are sending the signal to pin 13, which is also connected to this light on the board. If your light was flashing on and off before, it should now be doing pretty much the same thing. We have essentially recreated the code your Arduino came with installed.<blockquote >Note that the code is now physically sitting on the Arduino board and your Arduino is running the code. Your computer is NOT involved anymore, except to provide power to the Arduino board so it can stay on.</blockquote>Now to really make sure you’ve done this correctly and to start getting your kids familiar with controlling physical objects with the code, let’s modify the code.ASK YOUR KIDS: How do you think we could change how often the light flashes? Come up with other questions to ask them that they could intuitively figure out. You can be more direct if they don’t take the hint… What if we change how long it says to wait?, etc. This is where kids learn that they are in control of making it do what they want and not just following instructions. Then upload and run the code and watch the light pattern change.<h3 >Step 4. Add More Lights</h3>To add lights you will need a breadboard, which virtually every kit comes with. It’s the white one with all the holes. You will also need a few lights, just as many resistors, and enough wires to connect them all. Again, virtually every basic kit comes with this stuff.<blockquote >On the sides of the breadboard, the positive and negative columns of the breadboard are each one long connected piece of metal. Anything in a positive column is connected to anything else in a positive column. Anything in a negative column is connected to anything else in a negative column. In the center of the board it works differently. The lettered columns are NOT connected vertically. Instead, the numbered rows are connected horizontally. The gap in the middle is a break in the connection. So, the left side of a row number is all connected together, but separate from the right row. The right side of a row number is all connected together but separate from the left row. There is a good diagram of this in the SparkFun Inventors kit if you have that. </blockquote>An LED light has a positive and negative side, and it matters how they are connected. (They are not interchangeable.) In most kits, there is a flat side to the light with a shorter wire, and this is the negative wire.FIRST, UNPLUG YOUR ADUINO. You should never modify connections with power to the Arduino, so unplug it from the computer temporarily.Now that your Arduino is off, Plug an LED into your breadboard with the positive wire in slot a2, and the negative wire / flat side in slot a1. Then connect a jumper wire from slot e1 to a ground pin on the Arduino board (in the power section of the board). <figure><img src=https://projects.arduinocontent.cc/0eec0664-f28f-485d-8a27-e3a0e22ba508.png /><figcaption> </figcaption></figure> Next, add a resistor (I used 330 Ohm) and bridge the gap between e2 and f2 with it on the breadboard. If you use an external LED, you should always use a resistor to lower the voltage to the LED or you can damage it. Lastly, add a jumper wire to connect slot j2 to pin 13 on the Arduino board (in the digital section of the board). It should now look like this:<figure><img src=https://projects.arduinocontent.cc/7b50c6c3-f573-4d07-bbd9-068150708d38.png /><figcaption> </figcaption></figure>So the Connection from positive to negative / ground follows as PIN13 -> row 2 (right) -> resistor -> row 2 (left) -> LED(+) -> LIGHT -> LED(-) -> row 1 left side -> Ground.Double check all connections, and then plug the Arduino back into the computer and reconnect within mBlock as before.Once power is supplied, the Arduino will begin running the code that was last uploaded. So it’s probably blinking the LED light on the breadboard in the same pattern as the LED light on the Arduino unit near pin 13.<blockquote >This is important to note. Pin 13 has a special characteristic. It is always linked to the LED on the Arduino near it. Any signal you send through pin 13 will also activate the onboard LED. To see how it’s different you could 1. unplug the Arduino, 2. change the Scratch code to use pin 12 instead, 3. move the wire from pin 13 to pin 12 on the board, and then plug the Arduino back in, reconnect and upload the new code. This series of steps would safely convert everything to running through pin 12. You would now notice that the LED you installed on the breadboard is flashing, but now the LED on the Arduino is no longer flashing. That is because the LED on the Arduino itself only represents the signal from pin 13. This can be useful if you ever want to check if part of a code is running. You can tell the Arduino if that part of the code runs to activate pin 13 and you will know the code has run when the LED flashes. </blockquote>Now ask your kids once again, Do you think we could add more lights? Do you think we could make them blink in a certain order?, etc.You can hook up additional lights in almost exactly the same way (after unplugging the Arduino of course). You will need to use a different pin for each light if you want separate control, and you will need to hook them all to the ground somehow (Hint this is what the (-) column on the breadboard is for.Here is an example with three lights. There are more efficient ways to make these connections, but I am making them the same way as before so they are immediately understandable:<figure><img src=https://projects.arduinocontent.cc/46be5708-d4cb-49eb-a856-47d7bd0cb652.png /><figcaption> </figcaption></figure>Your kids can probably figure out the Scratch code on their own with some fiddling… BTW I am going to stop pointing out some of the little details as we move forward, like when you should be unplugging your Arduino, when to reconnect and upload new code, etc.Oh, back to the example Scratch code for this apparatus. My kids wrote this one:<figure><img src=https://projects.arduinocontent.cc/278c72c5-e26b-4a14-9a81-3aae56560dd1.png /><figcaption> </figcaption></figure>Using this code will make each LED flash on and then off in sequence.See if your kids can come up with other code examples creating different patterns with the lights!Hopefully from this first project your kids understand how to hook up LEDs, how the pins on the board work, what a ground is, what a resistor is for, and how to use Scratch to control things in the REAL WORLD.I’ll be looking to an input device to use for our next project to control the lights with.

Blinking Lights (#1) – Arduino with Scratch for Kids

Kids can use Scratch (mBlock) to program blinking lights with an Arduino.