Your breadboard is going to be your new best friend.
Breadboards allow you to create simple and complex circuits without soldering. That’s why it’s also sometimes referred to as a “solderless board.”
If you had to solder every time you built a circuit, you’d end up running through components fast, and any mistakes you make would be incredibly annoying to fix.
With a breadboard, you can quickly prototype circuits meaning you can move things around and experiment freely until you’re ready to solder.
The underlying structure of a breadboard is actually very simple and I expect you’ll be using it like a pro by the end of this article.
Before you start this tutorial, it’s recommended that you follow the GPIO pin tutorial first which includes introductory material about using the pins.
What you’ll need
To follow the steps in this Raspberry Pi breadboard tutorial, you’ll need:
- 1 breadboard
- 2 M-F jumper cables
- 1 M-M jumper cable
- 1 resistor (200-1000Ω)
- 1 LED
I recommend the REXQualis Complete Starter Kit which includes all of these items, plus many more.
How to use a breadboard
Breadboards have a perfectly logical layout for controlling currents.
At first glance, the breadboard just looks like a bunch of holes in a piece of plastic, but currents flow through them in very particular ways.
Down the center of the breadboard is the ravine. Every row on the left is connected (A-E), and every row on the right is connected (F-J).
Beaneath the plastic of each row is a metal strip. The metal functions as a conductor allowing charge to flow through the row. The five holes are simply access points to the metal strip.
At the top, you’ll see the columns are labeled with letters A-J and the rows have incrementing numerical labels. These labels are purely for your own reference to keep track of your connections.
Along the sides of the breadboard, you’ll see red and blue (sometimes black) lines running vertically. These are called the rails, and they function as an easy way to access power.
Each of the four rails has a single metal strip beneath the plastic. This means that connecting a power source to any point in a rail makes the current available to every other hole along the rail.
That’s the entire functionality of the breadboard’s design, but to really understand it, you’ll have to put it to use.
Let’s get hands-on by lighting up an LED with the Raspberry Pi.
How to power an LED using a breadboard
To get things started, we’ll feed some power to the breadboard with one of the 3V3 pins on the Raspberry Pi.
Grab one of your M-F jumper cables and make a connection from the 3V3 pin to the top hole in the positive rail.
With this connection made, the current can now travel along the entire rail. This means you can use a jumper cable with any of the holes in the rail to “jump” the current into any row, and that’s exactly what we’ll do next.
Take your M-M jumper cable, insert it into one of the holes in the left positive rail, and connect it to 10A.
Since 10A-10E share a conductor (the metal strip under the plastic), we can now use any of those holes to access the positive charge.
Connect the anode (long leg) of your LED into 10E, and the cathode (short leg) into 10F.
LEDs are diodes so they only conduct power in one direction which is why you need to place the anode into 10E. Bridging the ravine allows us to continue the circuit through 10F-10J instead of cramming everything into the left side.
Since we’re using 3V3, the power the LED receives will be at the upper limits of what it can handle. A resistor needs to be added to reduce the current so that the LED doesn’t burn out. 220Ω is perfect, but any value up to 1,000Ω will work fine.
Connect the resistor to 10J and one of the holes in the negative rail on the right side of the breadboard.
Another reason for bridging the ravine with the LED was so we could end up at the negative rail on the right side. It is a standard convention to move across the breadboard from left-to-right in this way.
Also, notice how we saved ourselves from needing another jumper cable by using the resistor to jump from row 10 into the negative rail.
The last step is to complete the circuit by returning to one of the Pi’s ground pins. Use your last M-F jumper to make a connection from the negative rail to a ground pin on your Pi. The LED should light up immediately.
Beautiful, isn’t it?
If you followed my GPIO pin tutorial then all of this probably clicked right away. The breadboard is so organized and is much more comfortable to use than plugging everything into jumper cables.
While this example illustrates how to use a breadboard, I think it’s also worthwhile to learn how not to use a breadboard.
Let’s get weird
What I showed you in this tutorial is totally sane and organized.
In fact, it’s so organized that I’m worried you may have learned some rules that aren’t actually rules. While you will certainly want to be organized, a breadboard is really just a collection of disconnected conductors free to be used however you wish.
To help you better crystallize what you’ve learned thus far, here is my completely ridiculous and wacky arrangement that still functions pefectly fine:
Power is fed to the positive rail, then it’s jumped to 10G on the right side. The current is going to move towards the ground no matter what, so it happily travels left to the LED’s anode in the neighboring hole. The LED then jumps the charge to 13D where the current heads back to the right to traverse the resistor all the way over to the negative rail which then returns to the ground completing the circuit.
So should you build your circuits like that? No way! It’s hideous!
But by understanding the underlying logic of a breadboard and how currents work, you can see why this frankenstein of a circuit is perfectly functional.
The original example is neatly organized and follows conventions, so I highly recommend building circuits like that, but I hope this example helped you to better understand your breadboard.
With a breadboard, you can iterate and experiment incredibly fast. You won’t need to worry about soldering until you’re prepared to create a final product.
If you want a project to try out your breadboard, stay tuned because I have a few on the way. You can use the box below to subscribe to future post notifications.
If you still have questions about how to use a breadboard with your Raspberry Pi, please post in the comments section below.