This instructable will guide you through how to make a decision maker Arduino. With the press of a button, the LEDs will light up in a random pattern. After a few seconds, a single LED will be lit. This is the final decision made by the Arduino. I have a particular purpose for my final product, but it can be used for many things. Do you ever have trouble picking a place to eat after a long day of work? Place 7 options on the board and click the button. In seconds you will have your mind made for you! This instructable will help you build confidence by creating a circuit with LEDs and possibly introduce you to a new component, the pushbutton.

During the weekend you can usually find my husband and me at a friends’ house playing an assortment of games. Typically, there is a bit of a debate when deciding who is going to be “Player 1”. We always try to make it fair, but we play so many games/times that sometimes we lose track. It always seems that a couple of people are always starting our games. This inspired me to make a device that could help my group have a fair and easy way to “Pick-a-Player”. Typically, our “game night” crew has seven participants. For this reason, I created this decision-maker to have 7 LEDs but you can adjust it to your own needs. Just for fun, I would have each player decorate a small paper cap that could be put over the LED to remember which one is theirs.

This is a perfect project for a beginner coder who is looking to extend their thinking into slightly more intricate coding and circuits. As a beginner coder myself, I can find myself feeling overwhelmed by the complexity of physical computing. At the end of this tutorial, you will find comprehension and extension questions as a way to help build your knowledge of coding and create more understanding within this project. These types of questions often help me to realize that I know more than I assume. I hope they can do the same for you!

Using this link, you can access a simulation of my circuit and code.

Step 1: Set Up Your Breadboard

Placing the LEDs

Start by placing your 7 LED in a column on different rows, placing the anode (long leg) in the same direction. Remember this as you continue to build your circuit
Using the 220 ohm resistors, place one leg of the resistor in the same row as the LEDs cathode (short leg). The other leg should connect to the - Rail.
Place one end of the jumper wires in the row with the LED anodes. The other ends should be placed in pins 2, 3, 4, 5, 6, 7, 8 respectively.
With another jumper wire, connect the - Rail to GND.

Placing pushbutton

Place the pushbutton with two prongs in the (e) column and two prongs in the f column.
Stick one leg of the 1K ohm resistor into the same row as one of the prongs on the (e) side. Stick the other leg in the - Rail.
In the same row as the resistor, stick one leg of a jumper wire with the other end placed in pin 12.
Connect the pushbutton to a power source by placing a jumper wire in the same row as the other prong on the (e) side. The remaining end of the wire is placed in 5V.

Step 2: Write the Code

Here is the link to my Arduino sketch where you can access my code.

This project was inspired by a different decision-maker that can be found here. I made changes to meet my needs for my project idea.

Step 3: Give It a Try!

Plug it in and press the button. This should start a random sequence on the LED, ending with one lit up for 10 seconds.
If this doesn’t happen, it’s time to debug.
- Take a look at your breadboard and check that your circuit is connected.
- Check over your code for errors. I always recommend double-checking that you wrote the correct pin numbers.

Step 4: (optional) Comprehension and Extension Questions

What line(s) set up the output pins?
If you wanted to change the amount of LED lights used which lines would you need to edit? Why?
How might you use a similar code to create a device to put players into two teams? Partners?
If you wanted the random light show to last longer, how would you do that?