I got a bubble machine for a fiver at The Works with the idea that I could control it somehow from a Raspberry Pi Zero W. It turned out to be quite a simple hack, with satisfying results.
Before adding any bubble mixture I turned the machine face down and took the six small screws out of the back so I could get the case open. Inside I found an electric motor, which turns the bubble paddles and drives the bubble-blowing fan and the back of the battery box. There’s quite a lot of empty space inside too, which means it’s not hard to squeeze the Raspberry Pi in there.
I de-soldered all the existing wires and replaced them with a short pair of wires from the battery compartment and another pair from the motor’s terminals. The original circuit included a button at the top of the case, which I’ve by-passed. I used my hot glue gun to fix the button-press in place at the top. I used the motor controller board from my CamJam Robotics kit to connect everything to the Pi, hooking the motor up to the “Motor A” terminals and power from the batteries to the VIN and GND posts (taking care to ignore my badly chosen wire colours). It’ll be interesting to see how much of a battery hog the little motor is.
I drilled a 10mm hole in the back of the case and elongated it with my Dremel to allow me to pass a Micro USB connector through which supplies power to the Pi. I used one of these extenders so I can use a proper power supply or a USB power pack if I want to take the bubble blower outdoors (and of course I will once summer comes!)
As far as hardware goes that’s it, so I wrote a few lines of python with GPIOzero which supports the CamJam Robotics kit. This made the coding side of the project super-simple, which I like very much. It really did take just a few lines to prove the Pi was controlling the motor and letting me remotely blow bubbles.
For the final touch I wanted to let anyone set the bubbles going by watching Twitter for the #blowbubbles hashtag. I recycled the code I wrote for the Tea Time Klaxon, so again it was quick and easy to get this going. The complete program is here if you’re interested.
Halloween is the time of year when makers add LEDS and sound effects to cheap goodies bought at pound shops and supermarkets.
I saw this skull in my local Asda, and thought it was ideal for a bit of modding. The cranium is quite rigid, and as it’s hollow there’s room to put stuff inside it. I used my Dremel to drill a 3mm hole in each eye socket, and to cut a square out of the bottom to allow access. I threaded orange LEDs through the hole in the base to each eye hole, and secured them in place with a dollop of hot glue, which also gave the LEDs a nice diffuse look inside the eye socket.
The plan was to have the eyes gently puslsing and to make spooky sound effects play as trick-or-treaters approached. I have a PIR detector in my box of bits and so I connected it to a Raspberry Pi and used the examples from the gpiozero documentation to write some code to use the sensor as a trigger. I’d tried using this sensor before for something and couldn’t get it to work, and again it defeated me. I’m sure there’s a trick to setting the sensitivity pot just right on these things, but I couldn’t make it work so chucked it back in the box for another day.
Instead I decided to add a button so the trick-or-treaters can scare themselves by playing the sounds if they’re brave enough! The illuminated arcade button that came as part of the Google AIY kit with issue 57 of the MagPi was perfect!
Sounds are played with a Pimoroni Speaker pHAT (I love these). I got the audio files from a Spooky sounds CD I bought at Woolies years ago. It plays just over an hour of gruesome sounds, and I edited a few short samples from it to use here.
Having got the electronics and software working I made a stand out of plywood, drilled holes for the button and to allow wires to pass through into to skull, and painted this black.
Paint it black
Once the paint was dry I put all the bits together. Having glued the LEDs to the skull earlier I had to take unfasten them now to let me hide the Raspberry Pi underneath the stand. Threading the wires from the Raspberry Pi, through the top of the stand, into the skull and then into the small holes in the eye sockets was tricky, but some patient fiddling about helped me get there. Really this is just a new version of the box of horrors I made at Halloween a couple of years ago, just don’t tell anyone I’m recycling my ideas!
It all started when we saw this lovely cocktail cabinet in a vintage shop. I said we could only buy it if we actually used it for booze, and not to store the usual crap a family of four hides in their cupboards.
Deal struck, we brought it home and have since enjoyed mixing and drinking cocktails at the weekend. It’s been fun finding a collection of drinks we enjoy, but we have recipes in books, recipes on my Notes app and recipes squirrelled away on bits of paper. There has to be a better way – and this is it!
I put a Hyperpixel 4 from Pimoroni on top of a Raspberry Pi and wrote a Python program using Laura Sach’s guizero library. Guizero lets you create simple graphical environments, and even for a learner like me it’s very accessible with clear documentation and examples.
My code is here on Github. The functions at the top are called for each relevant PushButton press, and the stuff at the bottom is the nuts and bolts holding together the app layout. I wanted to use photos as the background to the recipes as much as possible, these are stored as .jpg files which are called to fore when you press the button for that drink. As I remember to take more photos of the cocktails before we slurp sip them I’ll add more pictures to the backgrounds. The Hyperpixel display is great: it’s clear, colourful and the touch works well, even with my tiny buttons. By default the “bottom” of the screen is where the power plugs into the Raspberry Pi, and as I want to hide the plug away behind my little kiosk I used Pimoroni’s simple instructions to rotate the display 180 degrees, which moves the power connector to the back.
The Hyperpixel4 is small; it’s just a shade larger than the Raspberry Pi itself, but crams in 800 x 480 pixels. Even so, every line you display counts. My app looked great on screen but the title bar was using vital space. Despite reading the guizero documentation I couldn’t work out a way to make the title bar disappear, so I tweeted Laura and was delighted when she replied with a solution for me. Simply put, guizero is a friendly wrapper for a more complex Python library called Tkinter, and you can use those methods to modify objects in guizero. It just took one line of code, which Laura included in her tweet, but it made all the difference to how my programme looks on the Hyperpixel.
I wrote this program entirely on my Mac – there’s no GPIO interaction, nothing requiring the Raspberry Pi hardware at all, so I wondered if I could also regularly use this on my Mac without having to launch it from Terminal. A quick Google search led me to this page where I found out that with Python 3 installed it’s easy to right-click on a Python file and choose Open With -> Python Launcher. I dragged the icon onto my Dock and it opens when I click on it – just like a real app! I changed the power off button to a quit button so I don’t keep shutting down my laptop, and now I can easily browse these cocktail recipes on my Mac or on my little touch screen Raspberry Pi kiosk.
I’m at the age where things which were normal in my childhood are now described as vintage; cars, furniture, radios, and telephones.
I got an old BT rotary dialling phone from eBay a while ago, and have been hanging on to do something with it. We did use it as a phone for a while, but the handset speaker wasn’t great quality and the ring was so loud it made us all jump. This phone has two push-buttons on top – one stopped the bells ringing and the other was labelled “Recall” but didn’t seem to be working – at least not as I’d expect a button labelled recall to function.
I think my phone is a BT model 8746, having been wired with a plug-in jack at the factory. There are lots of websites with detailed information about these old phones which can help you identify the model you’ve got, host circuit diagrams and have useful repair and maintenance guides. Sam Hallas’ site is wonderfully detailed and britishtelephones.com was also useful. There’s also quite a bit of prior art with Raspberry Pis and rotary dialling phones, and I read these helpful posts from Dan Aldred and Giles Booth.
This is what I found inside the phone after I got the case off. I used this diagram to work out where the handset earpiece connected to the board, and the terminals for the handset cradle switch. Using croc clips I connected the dial to the Raspberry Pi’s GPIO and used Dan Aldred’s code to try to read the pulses. I got nothing, which was a bit worrying. I knew the dial was doing something as I used Giles’ LED trick to be able to see pulses. Next I connected the LED to the Raspberry Pi and wrote a few lines of code to make it flash from the GPIO. Nothing again, so I found another Pi (a 2B lurking unused) and tried again. This time the LED flashed and once connected to the phone’s dial I was able to count some pulses, so I diagnosed a dead GPIO on the Zero W and ordered a replacement – the 2B was never going to fit inside the phone!
Although I was now detecting pulses, the Pi was returning inconsistent results. I wasn’t going to be able to accurately report the number being dialled. So I abandoned the crocodile clips and cut the terminal connectors off the wires in the phone and soldered them to the Pi. I had hoped to be able to keep the phone in reasonably original condition so it could be returned to use as a telephone, but as this now wasn’t going to be an option I was free to get a bit more hacky with the phone. The transparent push-buttons on top of the phone looked like they’d make great light pipes so I hot glued an LED into the bottom of each one. These I connected to 3v from the Raspberry Pi via the two-way switch on the cradle, so when the phone is on the hook one lights up red until you pick up the handset when it switches off and the other button lights up green.
With the dial soldered to the Raspberry Pi I got a cleaner signal from the dial and could now reliably read the number dialled. I added some code to Dan’s example to play a different .wav file for each number between 1 and 9. Dialling 0 switches the Raspberry Pi off. My code is here if it’s helpful, but it doesn’t add much to Dan’s. I’ve chosen songs about phone calls or phone conversations, starting with Hanging on the Telephone by Blondie when you dial 1. To get the audio from the Pi into the handset I used a Pimoroni Speakerphat and wired it straight into the handset, having identified the wires for the speaker from the circuit diagram. The output was a bit too loud, so I soldered a 1k resistor into the circuit which made the volume more sensible.
At the moment the music carries on playing even after you hang up the receiver. I should have a go at using the hook switch to stop the playback, but I’m not sure I can squeeze many more wires into the space – it’s surprisingly cramped inside those old phones, despite how big they look from the outside!
We’re lucky enough to have two teenage boys in the house. One of them lurks in the gloom of his bedroom listening to loud, raucous music and doing god knows what on his computer until he can be lured out by offers of food. But sometimes the music is so loud, or the headphones so firmly clamped that he doesn’t hear the call of “Tea time!!!” wafting up the stairs. I could go up to his room to get him, but this is the 21st century and there has to be a better way.
That better way is the Tea Time Klaxon.
Now I just need to send a tweet featuring the secret hashtag to trigger flashing lights and a buzzer to alert the eldest that tea is ready.
Actually, I’ve wanted to find an excuse to make something with one of these LED towers for ages, because they just look so cool, and recently they’ve been discounted at Pimoroni which gave me a good excuse to get one. The tower needs 12v DC so you can’t drive it directly from a Raspberry Pi. Instead I bought a power supply from Amazon – this one, I think and a Pimoroni Automation pHat to handle the switching.
I made a little plywood stand to hide the gubbins, which looks quite neat with a couple of coats of varnish. Inside you can see the Raspberry Pi Zero with Automation pHat hot glued into a corner.
I wasn’t sure how easy it would be to get the pHat and LED tower talking to each other, but Pimoroni’s python library for the pHat is excellent. It’s simple to read and is well documented so even a non-coder like me can get going with it very quickly. I borrowed a bit of code from their Blinkt! library to help look out for the hashtag on Twitter and was soon ready to go.
My final code is on GitHub, and you can see that it really is straightforward.
I enjoyed making this, it turned out to be much simpler than I first expected. It’s meant as a bit of fun because both our boys are lovely really, even though one does occasionally text us from his room rather than actually come and speak to us.
It’s nice to think the things we make just work and will just keep on working, but obviously that’s not a realistic expectation. This week I’ve been back to two projects that needed a bit of love and attention.
I got both projects up and running again, and along the way learned a couple of things which will help me as I do more making.
The first problem was that the yellow LEDs on my global status indicator had stopped working. A quick look at the circuit showed all the connections looked sound, so I shorted across the button connectors to see if there was a problem there and the yellow LEDs all lit up.
Having diagnosed a problem with the button and checking I had a spare in my box of bits, I desoldered the connectors so I could pop it out of the map. Then I decided to try the button again, while it was out of its snug mounting hole. And of course it worked.
Old button works now its not snugly mounted in the frame.
What I think happened is that the hole I’d cut in the board was a bit too tight and was pinching the moving bits of the button that peek out of the sides, stopping something inside the button working properly. So I rotated the button 90 degrees, stuck it back in the map and checked it was going to work before re-soldering the connections to it.
What I learned: components stop working for lots of reasons, not just because they’re broken. I could have saved myself some time by just trying to reposition the button in its hole before starting to take things apart.
The second problem was a corrupt SD card on the Raspberry Pi running my desktop Twitter ticker. I know corrupt SD cards can be a problem for Raspberry Pi users, but until now I’ve never experienced it. When I built the case for the ticker I did consider making the Pi Zero W inside accessible, but that needed more steps and I just wanted the thing finished, so I glued the last panel in place rather than drilling pilot holes and finding some screws to close it up.
Now I used my Dremel to make pilot holes while the case was still in one piece, then levering from the bottom where any screwdriver marks wouldn’t hurt so much I managed to prise the back layer of plywood off the case fairly cleanly.
Raspberry Pi Zero W inside the Twitter ticker.
Then I managed to wriggle the Pi out of the case, reformat the memory card and flash a new OS to it using Etcher. Then I installed Twython and copied my code across and tried to run it. Of course it didn’t work because I’d forgotten to also install oauthlib.
It still didn’t run because I’d forgotten the Pimoroni one line installer for the ScrollpHat HD.
So eventually I got it working and screwed the case together.
Now includes screws!
I learned two things from this fix: if I’m going to blog about how I build these things I should be more comprehensive in writing up the software requirements, and I shouldn’t put Raspberry Pis in cases that aren’t easily openable.
The Google AIY kit that came with issue 57 of the MagPi makes a great internet radio. The cardboard box it comes with, however, is functional, but not wife-compliant so I wanted to find a better enclosure for it. For a while I mounted it behind a perspex Muji photo frame, which was OK but still not what I really wanted. Then I remembered the Pimoroni ARRR600 which had an internet radio inside an old Roberts.
Roberts radios are fantastic. They look amazing and, and are well built. When I first started working in radio the BBC’s local stations used them extensively for off-air cue at outside broadcasts and they survived a lot of rugged handling while still retaining their looks and sound quality. So I went to eBay and found a few for sale as “spares or repair.” I didn’t want to gut a functioning radio, or pay too much for just the case. I was out bid on a couple of R600s, but won the auction for a Roberts Rambler 2.
Taking it apart and removing the old innards was pretty easy. I had to make a mounting plate for my four new buttons, so cut down some 3mm acrylic sheets I had left over from something else, and carefully drilled holes in the right places, using the top cover as a template. I fitted the new buttons and pots, and soldered all the wires to them and to the Google Voice hat. I used the original speaker from the radio, connecting it to the hat via the volume pot so it can be adjusted without having to bother the AIY kit. (Although you can still say “Volume up” or “Volume down” to it if you like). The pulsing LED is mounted underneath the top panel, and shines through nicely. As there are plenty of spare GPIOs available on the hat I connected the buttons as mentioned, and added three extra LEDs too. These don’t do anything at the moment, but I suspect I could add some code for them if inspiration strikes me.
I used KTinkerer’s code and excellent blog post to get the BBC radio stations playing on the AIY kit, but I modified some of the station names to be more on-brand and swapped my BBC locals for Radio Nottingham from their example.
I’m pleased with the outcome of this, and it sits nicely on the desk in the front room with my Twitter ticker. Strangely the LED connected to GPIO 5 is always dimly lit. If anyone has any idea what might be causing that, or any other feedback, I’d be interested to hear in the comments.
I’ve already made a couple of Raspberry Pi powered Twittertickers with wildly different display sizes and, honestly, levels of success. Most importantly, they’ve both failed to be wife-compliant; that is they weren’t finished to a standard where I’d be allowed to leave them out and actually make use of them!
With wifi now built in to the Raspberry Pi Zero W, and Pimoroni’s neat Scroll pHat HD available, I wanted to have another go at this, and having learned a lot of general makery-ness over the last couple of years I thought I could manage to box it up in a smart display.
The code was the easiest part of this project; I just had to modify my previous efforts to work with the Scroll pHat HD rather then the PaPirus Zero or LED matrices I’d used before and add some GPIOZero bits to get the buttons working. You can see the code on GitHub.
Raspberry Pi Zero W lies flat, but hidden behind the Scroll pHat HD and ProtoZero board
The hardware was straightforward too. I used a right-angle header on the Pi which connected to a ProtoZero board with a long female header to plug into the Scroll pHat HD. I soldered the wires for my two buttons onto the ProtoZero. I needed the Pi to lie flat so I could connect power into it while the display was standing upright. (I’ve used ProtoZero boards in severalof my projects, they’re really useful for breaking out GPIOs and neatly soldering your buttons, LEDs and other bits and pieces onto.)
The case was the bit I expected to find most difficult. I wasn’t good at woodwork at school, and haven’t done anything like this before.
I did a lot of head-scratching and drawing before making any cuts.
But I had a plan.
I thought I could sandwich together sheets of plywood with a hole cut through the middle of them to make the case. There was some transparent red acrylic left over from supersecretproject#2 that would make a nice diffuser for the really very bright LEDs on the display.
So I did a lot of measuring of the assembeled hardware and drew my pictures, before heading out to treat myself to a jigsaw. This was a good decision.
It doesn’t matter how scruffy the hole in the middle is, as long as there’s clearance to get the Raspberry Pi Zero W and Scroll pHat HD through there.
I cut the plywood into biscuits and then drilled out the corners of the big hole I was about to jigsaw out of the piece. I made nine of these to accommodate the hardware, and then the front and back plates with feet to stand the box up on the table. I made a tidier hole in the front panel to show the display through, but drilled just a 12mm hole in the bottom corner of the back piece for the power lead. I used wood glue to glue the front half together in one stack, including the plastic and front panel, and then glued the back half separately. I drilled holes for the buttons into the top of this back half and then sanded everything down, rounded the corners slightly and gave it a varnish. This really brought out the colours in the different layers of ply and I think looks rather nice. I pushed the nuts to secure the buttons onto the wires, soldered up the buttons and threaded then into the holes I’d drilled into the top.
Now I did a last test of everything before gluing it all up and happily found everything worked as it should.
Then I glued the rear half onto the front, pushing the Scroll pHat HD right up against the acrylic, threaded the power wire through the rear hole and plugged it back into the Pi and glued the final back slice onto the sandwich.
When it all dried everything still worked, but the feet weren’t quite the same height and it wobbled when you pressed the buttons, so I sanded a few millimetres off the offending foot and gave myself a strong and stable foundation for the project!
I’m pleased with how this one has come out, and think it’s certainly wife-compliant, but as always I’d love to hear your suggestions for improvements in the comments.
UPDATE:Alex Burns tried to run the code from GitHub and found it wouldn’t run. This is because the Twython OAuth packages only install for Python 3 so you have to force the program to run in Python 3. To do this I typed the following at the command line: python3 scrolltwitter.py
ANOTHER UPDATE: It turns out that buttons and a display make a versatile hardware platform, so to grant a request from a family member I just had to write a new program to create a “Sleeps-til-Christmas-ometer”1.
When we redecorated the hall we went to B&Q in search of some wallpaper to run up the stairs. You know the stuff; probably floral. But then we saw this, and just had to get it.
We’re not massive VW fans, but the dream is to get some sort of camper van when we retire and hit the road, so it’s a little nod towards what might be.
When Cora, our neighbour, gave up her Golf she kept the badges off it’s boot and radiator, and when she saw this wallpaper she gave us one of them. I went to eBay and got a display frame to put it in, and it’s lived on the radiator shelf at the bottom of the stairs since then.
But it’s not felt quite finished; after all, everything can be improved by adding LEDs to it. There was (of course) a spare Raspberry Pi Zero and Blinkt! stick in my makers’ box, so I Dremmelled a Blinkt! sized slot in the bottom of the frame, poked the LEDs through and screwed the Zero onto the bottom of the box.
I’ve not done any fancy code, it just runs the rainbow.py script from Pimoroni’s Blinkt! library.
PS: This video was made with Apple’s Clips app. I really made it as an excuse to play with the app, which is a lot of fun and not that difficult to get started with.
We love our cocktail cabinet, bought at a vintage shop in Northallerton. But you can improve everything by adding LEDs to it, right?
After finishing my K9 build I’ve time to spend on a few smaller ideas I’ve had kicking around, like how to make the cocktail cabinet glow. I splurged on a Mote kit from Pimoroni and the pHat to go with it. I made a simple frame from some plywood that was in the shed and screwed the Mote strips to the outside edges. A Pi Zero W went in the middle and I threaded the cables through the gaps I’d left at the corners.
A couple of screw eyes and some picture wire let me hang it on a picture hook behind the cabinet. I’ve just got one of the example scripts provided by Pimoroni running for the rainbow effect, but in the future I’d like to make the LEDs flash or change colour in response to a Twitter hashtag like #cocktailtime
I also think it’s time for that wallpaper to go, and paint a nice clean white wall instead.