Raspberry Pi Digest – 10th June 2021 – a different way of blogging!

I’m trying something new out – a sort-of digest of Pi-related things I’ve found this week. Let me know what you think of the idea of these combined posts in the comments! đŸ™‚

Air quality lamp

Guillaume Slizewicz has created a Raspberry Pi Zero W-driven lamp that lets you know about air quality. Called Canari, it turns air pollution data from APIs into light patterns. The two APIs are from smartcitizen.me and sensor.community. You can read more here and see a video on Vimeo or watch it below.

Pico VGA Library

Miroslav Nemecek has been busy developing a VGA library for the Raspberry Pi Pico. Able to output from the Pico to a VGA monitor in either PAL or NTSC, the library has been developed with gaming applications and technical demos in mind. Details of the wiring involved and the way you compile the library (Windows only, sorry) are available here, along with LOTS of lovely documentation. You can see a demo in the video below:

Apple eMate – a portable Raspberry Pi

“Billy the Kid” has taken an old Apple eMate 300 and converted it to house and use a Raspberry Pi 4 8GB model. This rare machine was launched in 1997 by Apple and had a screen and keyboard. This is a great project to make a Pi portable, although the procedure is long, complicated and definitely not something you want to mess up – Billy has estimated the cost at over $400. You can see the build over on YouTube or below (you might want to turn your volume down a bit as I almost jumped out of my chair when it started!):

Bop that Minecraft!

Seth Altobelli decided to make Minecraft just that little bit more difficult to control by using a Raspberry Pi Pico as the control board for a Bop It toy. You steer using an accelerometer that he added and the you hit one of the buttons to move. The other buttons are used for other commands and for jumping. He doesn’t go into the coding too much, but I assume he’s using the Pico to translate between the Bop It’s controls and a HID input. It makes Minecraft much easier incredibly difficult to control, but it’s certainly a cool project! You can see details of the “Technoblade” build and a long demo over on YouTube or watching the video below:

Build a simple physical mute button for video conferencing on Zoom using a Raspberry Pi Pico

Miguel Grinberg has written a really great beginners’ tutorial to the world of USB HID using the Raspberry Pi Pico. For this project, he adds a Pico to a breadboard then hooks up a simple momentary button. Pressing the button sends a keypress to Zoom which mutes and unmutes the software. The software is CircuitPython, which has USB_HID already available and it can easily be expanded to send other commands, like turning your video off, for example. You can read Miguel’s tutorial here.

For a more comprehensive StreamDeck example, take a look here.

Create a weather forecasting station using a Feather S2 and an OLED

At the moment, I am waiting for the second version of my PCB for the PicoPicorder. In a departure from my regular making, I decided to buy a Feather S2 from Pimoroni. This is a Feather-format board with built-in WiFI that comes with CircuitPython pre-installed (although I believe you can install MicroPython if you want to – but in the end, I stuck with CircuitPython). If you want to know more about the Feather S2, take a look at this website.

But what to do with it?

My step-daughter has recently started a (very) local waitressing job whilst waiting to find her dream job (we hope!). Until today, this was all very outside-based, due to COVID restrictions in the UK. WIth today’s slight relaxation of restrictions, she’ll be indoors some of the time, but they’re (very sensibly) keeping the outside area. I decided, therefore, that she needed a way of knowing what the weather was going to be like for upcoming shifts.

I also bought a FeatherWing OLED at the same time so decided to use that as the readout for a weather forecasting station. I decided that I didn’t just want to sandwich the two together (because that would give me quite a tall profile and I wanted something flatter. This meant either a PCB or a piece of stripboard. I will be going for the latter eventually, but first of all I decided to breadboard the two boards (as you can see in the image above). This involved soldering male headers to both boards, which was fairly easy (once I’d got used to my new varifocals!)

After sorting out the circuit, I wrote some code that would allow me to:

  • Select a location to forecast the weather for (because I wanted it to be multi-user, so added in my parents’ home town and the in-laws’ home town). (Button A on the OLED).
  • Retrieve a forecast from the OpenWeatherMap.org API (which I’d previously signed up for, on their Free tier). (Button B).
  • Display the current weather and the next 5 forecast weather readings. (Button C).

All my code is on GitHub if you’d like to take a look. Feel free to re-use and adapt if you’d like to. The API returns JSON, and there’s some conversion functions in there to get the data into a more manageable (smaller) packet. There’s probably a more efficient way to use the displayio library, but I wanted to get the code done in a day. I learned loads about Python, loops especially, doing this!

Here is a video demo of the device as it currently is on the breadboard. As you can imagine, it won’t take much to convert this to a stripboard version! I will then add a 3D printed box to put it in.

Let me know what you think of the project – and if you can think of any additional bells and whistles I can add!

Find the current location of the International Space Station and display it on an e-ink display with a Raspberry Pi

Graeme over at Raspberry Connect has created this nifty little project using a Raspberry Pi Zero W and a small e-ink display from SeeedStudio.

Using an open API, he grabs the position of the ISS and then plots it as a red dot on a world map (with a red trail to show its path). He also works out which geographical location the ISS is currently over and displays that as well, along with how far away that is from his current UK-based location.

It’s a great project, especially for kids learning where places are on the Earth and who have an appreciation of Space-type… things.

Graeme has documented the entire project over on his blog and it is well worth a look.


Sending and receiving messages from the grandkids with the Raspberry Pi-powered Yayagram

Spain-based Manu, who you can find on Twitter, needed to help his 96-year old grandmother communicate with her grandchildren. She is hard-of-hearing and not very tech-savvy, so having her use a mobile phone is a bit of a non-starter. To solve the problem, Manu built the Yayagram (Yaya means ‘Granny’ in Castilian) which uses a Raspberry Pi to communicate with the Telegram service.

The contraption is a box (as pictured) which connects Manu’s granny, via a jack cable, to her grandchildren and allows her to send voice messages to them by pressing and holding the red button. His granny, therefore, need only connect the jack cable to the appropriate grandchild’s port (or to the ‘send all’ port), record a message using the inbuilt microphone, release the button and away the message goes.

The grandchildren receive the message and can also send a reply (or an initial message) which gets printed out by the Yayagram using a thermal printer. Inside the box is a Raspberry Pi 4, connected up to all the peripherals and indicator LEDs over USB and GPIO.

Manu has found that the Yayagram has made his grandmother more independent, and, of course, more communicative with her family, especially in the times of COVID-19 restrictions.

You can read slightly more about the project, and see more photos, over on this Twitter thread.

Manu, his grandmother and the Yayagram

Make your own Ghostbuster PKE Meter prop using a Raspberry Pi and SenseHAT

Starscream205 on Instructables has written up this great handheld, battery-powered project. It is a PKE Meter, popularised in the movie (and cartoon) Ghostbusters. Made out of Raspberry Pi 3B+, a SenseHAT, a night-vision camera (with IR lights) and a 3.5″ low-resolution monitor, the PKE Meter is, of course, “just” a prop, but it looks cool and takes pictures at the click of a button. The 3D-printed case makes it look the part! With a little bit more work using the SenseHAT’s sensors and the feed from the camera, you could take it even further if you wanted to.

You can read all about it on Instructables.