Tag Archives: Raspberry Pi 3B+

Raspberry Pi calls out your custom workout routine

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If you don’t want to be tied to a video screen during home workouts, Llum AcostaSamreen Islam, and Alfred Gonzalez shared this great Raspberry Pi–powered alternative on hackster.io: their voice-activated project announces each move of your workout routine and how long you need to do it for.

This LED-lit, compact solution means you don’t need to squeeze yourself in front of a TV or crane to see what your video instructor is doing next. Instead you can be out in the garden or at a local park and complete your own, personalised workout on your own terms.

Kit list:

Raspberry Pi and MATRIX Device

The makers shared these setup guides to get MATRIX working with your Raspberry Pi. Our tiny computer doesn’t have a built-in microphone, so here’s where the two need to work together.

MATRIX, meet Raspberry Pi

Once that’s set up, ensure you enable SSH on your Raspberry Pi.

Click, click. Simple

The three sweet Hackster angels shared a four-step guide to running the software of your own customisable workout routine buddy in their original post. Happy hacking!

1. Install MATRIX Libraries and Rhasspy

Follow the steps below in order for Rhasspy to work on your Raspberry Pi.

2. Creating an intent

Access Rhasspy’s web interface by opening a browser and navigating to http://YOUR_PI_IP_HERE:12101. Then click on the Sentences tab. All intents and sentences are defined here.

By default, there are a few example sentences in the text box. Remove the default intents and add the following:

[Workout]start [my] workout

Once created, click on Save Sentences and wait for Rhasspy to finish training.

Here, Workout is an intent. You can change the wording to anything that works for you as long as you keep [Workout] the same, because this intent name will be used in the code.

3. Catching the intent

Install git on your Raspberry Pi.

sudo apt install git

Download the repository.

git clone https://github.com/matrix-io/rhasspy-workout-timer

Navigate to the folder and install the project dependencies.

cd rhasspy-workout-timernpm install

Run the program.

node index.js

4. Using and customizing the project

To change the workout to your desired routine, head into the project folder and open workout.txt. There, you’ll see:

jumping jacks 12,plank 15, test 14

To make your own workout routine, type an exercise name followed by the number of seconds to do it for. Repeat that for each exercise you want to do, separating each combo using a comma.

Whenever you want to use the Rhasspy Assistant, run the file and say “Start my workout” (or whatever it is you have it set to).

And now you’re all done — happy working out. Make sure to visit the makers’ original post on hackster.io and give it a like.

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Raspberry Pi won’t let your watched pot boil

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One of our favourite YouTubers, Harrison McIntyre, decided to make the aphorism “a watched pot never boils” into reality. They modified a tabletop burner with a Raspberry Pi so that it will turn itself off if anyone looks at it.

In this project, the Raspberry Pi runs facial detection using a USB camera. If the Raspberry Pi finds a face, it deactivates the burner, and vice versa.

There’s a snag, in that the burner runs off 120 V AC and the Raspberry Pi runs off 5 V DC, so you can’t just power the burner through the Raspberry Pi. Harrison got round this problem using a relay switch, and beautifully explains how a relay manages to turn a circuit off and on without directly interfacing with the circuit at the two minute mark of this video.

The Raspberry Pi working through the switchable plug with the burner

Harrison sourced a switchable plug bar which uses a relay to turn its own switches on and off. Plug the burner and the Raspberry Pi into that and, hey presto, you’ve got them working together via a relay.

The six camera setup

Things get jazzy at the four minute 30 second mark. At this point, Harrison decides to upgrade his single camera situation, and rig up six USB cameras to make sure that no matter where you are when you you look at the burner, the Raspberry Pi will always see your face and switch it off.

Inside the switchable plug

Harrison’s multiple-camera setup proved a little much for the Raspberry Pi 3B he had to hand for this project, so he goes on to explain how he got a bit of extra processing power using a different desktop and an Arduino. He recommends going for a Raspberry Pi 4 if you want to try this at home.

Kit list:

  • Raspberry Pi 4
  • Tabletop burner
  • USB cameras or rotating camera
  • Switchable plug bar
  • All of this software
It’s not just a saying anymore, thanks to Harrison

And the last great thing about this project is that you could invert the process to create a safety mechanism, meaning you wouldn’t be able to wander away from your cooking and leave things to burn.

We also endorse Harrison’s advice to try this with an electric burner and most definitely not a gas one; those things like to go boom if you don’t play with them properly.

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This Raspberry Pi–powered setup improves home brewing

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We spied New Orleans–based Raspberry Pi–powered home brewing analysis and were interested in how this project could help other at-home brewers perfect their craft.

Raspberry Pi in a case with fan, neatly tucked away on a shelf in the Danger Shed

When you’re making beer, you want the yeast to eat up the sugars and leave alcohol behind. To check whether this is happening, you need to be able to track changes in gravity, known as ‘gravity curves’. You also have to do yeast cell counts, and you need to be able to tell when your beer has finished fermenting.

“We wanted a way to skip the paper and pencil and instead input the data directly into the software. Enter the Raspberry Pi!”

Patrick Murphy

Patrick Murphy and co. created a piece of software called Aleproof which allows you to monitor all of this stuff remotely. But before rolling it out, they needed somewhere to test that it works. Enter the ‘Danger Shed’, where they ran Aleproof on Raspberry Pi.

The Danger Shed benefits from a fancy light-changing fan for the Raspberry Pi

A Raspberry Pi 3 Model B+ spins their Python-based program on Raspberry Pi OS and shares its intel via a mounted monitor.

Here’s what Patrick had to say about what they’re up to in the Danger Shed and why they needed a Raspberry Pi:

The project uses PyCharm to run the Python-based script on the Raspberry Pi OS

“I am the founder and owner of Arithmech, a small software company that develops Python applications for brewers. Myself and a few buddies (all of us former Army combat medics) started our own brewing project called Danger Shed Ales & Mead to brew and test out the software on real-world data. We brew in the shed and record data on paper as we go, then enter the data into our software at a later time.”

Look how neat and out of the way our tiny computer is

“We wanted a way to skip the paper and pencil and instead input the data directly into the software. Enter the Raspberry Pi! The shed is small, hot, has leaks, and is generally a hostile place for a full-size desktop computer. Raspberry Pi solves our problem in multiple ways: it’s small, portable, durable (in a case), and easily cooled. But on top of that, we are able to run the code using PyCharm, enter data throughout the brewing process, and fix bugs all from the shed!”

The Raspberry Pi in its case inc. fan

“The Raspberry Pi made it easy for us to set up our software and run it as a stand-alone brewing software station.”

Productivity may have slowed when Patrick, Philip, and John remembered you can play Minecraft on the Raspberry Pi

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Be a better Scrabble player with a Raspberry Pi High Quality Camera

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One of our fave makers, Wayne from Devscover, got a bit sick of losing at Scrabble (and his girlfriend was likely raging at being stuck in lockdown with a lesser opponent). So he came up with a Raspberry Pi–powered solution!

Using a Raspberry Pi High Quality Camera and a bit of Python, you can quickly figure out the highest-scoring word your available Scrabble tiles allow you to play.


  • Raspberry Pi 3B
  • Compatible touchscreen
  • Raspberry Pi High Quality Camera
  • Power supply for the touchscreen and Raspberry Pi
  • Scrabble board

You don’t have to use a Raspberry Pi 3B, but you do need a model that has both display and camera ports. Wayne also chose to use an official Raspberry Pi Touch Display because it can power the computer, but any screen that can talk to your Raspberry Pi should be fine.


Firstly, the build takes a photo of your Scrabble tiles using raspistill.

Next, a Python script processes the image of your tiles and then relays the highest-scoring word you can play to your touchscreen.

The key bit of code here is twl, a Python script that contains every possible word you can play in Scrabble.

From 4.00 minutes into his build video, Wayne walks you through what each bit of code does and how he made it work for this project, including how he installed and used the Scrabble dictionary.

Fellow Scrabble-strugglers have suggested sneaky upgrades in the comments of Wayne’s YouTube video, such having the build relay answers to a more discreet smart watch.

No word yet on how the setup deals with the blank Scrabble tiles; those things are like gold dust.

In case you haven’t met the Raspberry Pi High Quality Camera yet, Wayne also did this brilliant unboxing and tutorial video for our newest piece of hardware.

And for more projects from Devscover, check out this great Amazon price tracker using a Raspberry Pi Zero W, and make sure to subscribe to the channel for more content.

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Make it rain chocolate with a Raspberry Pi-powered dispenser

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This fully automated M&M’s-launching machine delivers chocolate on voice command, wherever you are in the room.

A quick lesson in physics

To get our head around Harrison McIntyre‘s project, first we need to understand parabolas. Harrison explains: “If we ignore air resistance, a parabola can be defined as the arc an object describes when launching through space. The shape of a parabolic arc is determined by three variables: the object’s departure angle; initial velocity; and acceleration due to gravity.”

Harrison uses a basketball shooter to illustrate parabolas

Lucky for us, gravity is always the same, so you really only have to worry about angle and velocity. You could also get away with only changing one variable and still be able to determine where a launched object will land. But adjusting both the angle and the velocity grants much greater precision, which is why Harrison’s machine controls both exit angle and velocity of the M&M’s.

Kit list

The M&M’s launcher comprises:

  • 2 Arduino Nanos
  • 1 Raspberry Pi 3
  • 3 servo motors
  • 2 motor drivers
  • 1 DC motor
  • 1 Hall effect limit switch
  • 2 voltage converters
  • 1 USB camera
  • “Lots” of 3D printed parts
  • 1 Amazon Echo Dot

A cordless drill battery is the primary power source.

The project relies on similar principles as a baseball pitching machine. A compliant wheel is attached to a shaft sitting a few millimetres above a feeder chute that can hold up to ten M&M’s. To launch an M&M’s piece, the machine spins up the shaft to around 1500 rpm, pushes an M&M’s piece into the wheel using a servo, and whoosh, your M&M’s piece takes flight.

Controlling velocity, angle and direction

To measure the velocity of the fly wheel in the machine, Harrison installed a Hall effect magnetic limit switch, which gets triggered every time it is near a magnet.

Two magnets were placed on opposite sides of the shaft, and these pass by the switch. By counting the time in between each pulse from the limit switch, the launcher determines how fast the fly wheel is spinning. In response, the microcontroller adjusts the motor output until the encoder reports the desired rpm. This is how the machine controls the speed at which the M&M’s pieces are fired.

Now, to control the angle at which the M&M’s pieces fly out of the machine, Harrison mounted the fly wheel assembly onto a turret with two degrees of freedom, driven by servos. The turret controls the angle at which the sweets are ‘pitched’, as well as the direction of the ‘pitch’.

So how does it know where I am?

With the angle, velocity, and direction at which the M&M’s pieces fly out of the machine taken care of, the last thing to determine is the expectant snack-eater’s location. For this, Harrison harnessed vision processing.

Harrison used a USB camera and a Python script running on Raspberry Pi 3 to determine when a human face comes into view of the machine, and to calculate how far away it is. The turret then rotates towards the face, the appropriate parabola is calculated, and an M&M’s piece is fired at the right angle and velocity to reach your mouth. Harrison even added facial recognition functionality so the machine only fires M&M’s pieces at his face. No one is stealing this guy’s candy!

So what’s Alexa for?

This project is topped off with a voice-activation element, courtesy of an Amazon Echo Dot, and a Python library called Sinric. This allowed Harrison to disguise his Raspberry Pi as a smart TV named ‘Chocolate’ and command Alexa to “increase the volume of ‘Chocolate’ by two” in order to get his machine to fire two M&M’s pieces at him.



In his video, Harrison explaining that other snack-launching machines involve a spring-loaded throwing mechanism, which doesn’t let you determine the snack’s exit velocity. That means you have less control over how fast your snack goes and where it lands. The only drawback to Harrison’s model? His machine needs objects that are uniform in shape and size, which means no oddly shaped peanut M&M’s pieces for him.

He’s created quite the monster here, in that at first, the machine’s maximum firing speed was 40 mph. And no one wants crispy-shelled chocolate firing at their face at that speed. To keep his teeth safe, Harrison switched out the original motor for one with a lower rpm, which reduced the maximum exit velocity to a much more sensible 23 mph… Please make sure you test your own snack-firing machine outdoors before aiming it at someone’s face.

Go subscribe

Check out the end of Harrison’s videos for some more testing to see what his machine was capable of: he takes out an entire toy army and a LEGO Star Wars squad by firing M&M’s pieces at them. And remember to subscribe to his channel and like the video if you enjoyed what you saw, because that’s just a nice thing to do.

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Build a Raspberry Pi laser scanner

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You really don’t need anything too fancy to build this Raspberry Pi laser scanner, and that’s why we think it’s pretty wonderful.

Rasperry Pi 3D Laser Scanner

Cornell University: ECE 5725 Michael Xiao and Thomas Scavella

Building a Raspberry Pi laser scanner

The ingredients you’ll need to build the laser scanner are:

  • Raspberry Pi
  • Raspberry Pi Camera Module v2
  • Stepper motor and driver
  • Line laser
  • Various LEDs, resistors, and wires
  • Button

To complete the build, access to a 3D printer and laser cutter would come in handy. If you don’t have access to such tools, we trust you to think of an alternative housing for the scanner. You’re a maker, you’re imaginative — it’s what you do.

How does the laser scanner work?

The line laser projects a line an object, highlighting a slice of it. The Raspberry Pi Camera Module captures this slice, recording the shape of the laser line on the object’s surface. Then the stepper motor rotates the object. When the object has completed a full rotation and the camera has taken an image of every slice, the Raspberry Pi processes all the images to create one virtual 3D object.

Instructables user mfx2 has written a wonderful tutorial for the project, which also includes all files needed to build and program your own version.

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