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.

Guest post – Building a custom Raspberry Pi Pico-powered WiFi temperature sensor using MQTT and CircuitPython

David Booth is here with another guest post. This time a custom temperature sensor using a Raspberry Pi Pico and a self-designed PCB.


A custom, low power temperature sensor powered by a Raspberry Pi Pico with an LCD display and WiFi connectivity for integration into an MQTT home automation hub.


For a number of years now, I’ve been wanting to monitor room temperatures across my house to assess the effect of multiple heating sources and insulation efficiency. Best practice would dictate that I have multiple sensors running in parallel to get data points that are relative to one another. For multiple sensors to be running constantly, I’d prefer it to be low powered and low cost to maximise the number of units I can have in the setup. For ease of setup, it would be preferable for each unit to be wireless to allow temperature data collection to be performed in a single location and for each unit to only require a power connection.


1. In the early days

Since the Pico came about, it became the obvious choice over a Pi Zero due to its low power consumption and the fact that it didn’t matter if the device lost power at any time. Stage one was to learn how to integrate the Pico with a screen and a temperature sensor. The Pico Omnibus from Pimoroni with dual expansion board pins meant I could start by adding a dedicated Pico Display and still have easy access to the GPIO pins for connecting other boards. At the time of launch, there were no Pico add-on boards with temperature sensors that I could find so I chose a BMP280 temperature/humidity I2C sensor due to its low cost and small size.

The first working prototype stored the average temperature over an hour and displayed this as a graph for a 24 hour period.

2. Temporal progress

To further the project, the next stage was to make the Pico able to wirelessly transmit the data to some sort of hub. I already have an MQTT broker for my custom Raspberry Pi-powered network doorbell and automated LED porch lights so it made sense to link the two systems together.

When designing, the Pico was new so there were no dedicated WiFi systems with documentation on how to connect them together. That was until Les Pounder from Tom’s Hardware did a great writeup on how to use the AirLift WiFi Featherwing with the Pico. Coincidentally, I had already bought an AirLift with the intention to “mesh” it with the Pico. This, however, came with the caveat that I would need to swap from the default Raspberry Pi MicroPython firmware to CircuitPython firmware. Thinking this was going to be a nightmare, I was happy to find out it was painless and actually made development much easier. With CircuitPython, the Pico was now accessible as a USB storage device so I could edit the files directly on the Pico using a standard text editor of my choice (not forced into using something like Thonny). It also had the added benefit that the Pico auto-reloaded my code when the source code files were modified. I just had to remember to copy over the Adafruit CircuitPython packages necessary to interact with the ESP32 SPI WiFi module and BMP280 temperature sensor.

The only downside I found was that the Adafruit CircuitPython packages for the Pico Display worked differently to the Pimoroni MicroPython packages and were less helpful when it came to example code. I should be clear: it did have a few examples, but they were for static display of information, not changeable, constantly-updated data like I’d need. It therefore took a bit of “experimenting” to port my code over to the new style.

3. Moving away from the “breadboard”

The prototype was now operational but was a mess of wires connecting the WiFi and temperature sensor to the Pico as neither module fitted onto the Pimoroni Pico Omnibus board and I had to use jumper wires to get to this stage.

Wanting to make a custom PCB to neaten everything up, I started with a piece of stripboard and soldered the header pins necessary to house the four boards how I wanted them, but after soldering ninety three header pins and still having to then solder twenty seven additional wires (in a specific order) on the back to connect everything up, I realised it was just as easy (and probably quicker) to draw up a PCB in KiCad and get it fabricated.

Having used KiCad previously to design Raspberry Pi HATs for my Pi Wars entry over the last few years, I found this fairly easy. The board design would be basic: some header pins and traces to link them together based on my rats nest of wires. I had this designed in an hour or two. Knowing that the PCB fabricator wouldn’t care what shape the board was, I decided that it would not be a simple rectangle. Hence why I chose to add mount holes on “wings” which jut out to give it a distinctive look.

Another consideration for board design was that it would be using WiFi. I knew that adding a ground plane would potentially reduce the wireless signal (it creates a basic Faraday Cage) so I skipped that step.

4. Fabrication and the results

Following the JLCPCB, it was a simple case of exporting the gerber files and sending them to JLCPCB for fabrication. The cost of fabrication was a touch over £15 for five boards which they fabricated and delivered in a little under two weeks.

The first thing I did was to solder on header pins and then I plugged in the four boards.

Surprisingly, my design worked first time (there’s normally something I forget to link together or add).

Mounting to the wall was easy with the four pre-drilled mounting holes in the design. I found that orientation is the key as the temperature sensor reads a degree or so higher if it is oriented directly above the Pico and the screen. Simply rotating the whole thing so the temp sensor is on the bottom resolves this and the screen can be rotated in-code so it reads the right way up.

Overall, I am very happy with the design and will start assembling multiple boards ready for deployment. All that remains is to add a process in the MQTT hub to collect the temperature readings and display them on an internal web page.

Code and PCB files

For anyone interested in replicating the project, here is a link to my Github repository which contains the source code and KiCad PCB files.

Plant moisture detector uses a Raspberry Pi Pico for a low-cost, easy to implement project – the 3D-printed enclosure is an added bonus

Spencer Organ recently went to the virtual Preston Raspberry Jam which had a gardening theme to talk about his project – a Raspberry Pi Pico watering can. You can see the innards above. Costing under £15, the project helps to monitor a single plant (in Spencer’s case a Sweetpea plant) and tell you the soil moisture level. The level is displayed  as a nice graph on a cheap SSD and the whole thing is powered by a Raspberry Pi Pico. A 3D-printed enclosure in the shape of a watering can keeps the whole thing tidy.

You can find details, including how to reproduce it, on Spencer’s Maker Cupboard blog.

You can watch Spencer talk about his project by going to this YouTube video – open up the full description of the video and then click to skip directly to his talk.

Taking the Cytron Maker Pi Pico out for a spin with the Raspberry Pi Pico

Tony Goodhew has been in touch about some experiments he has run on the new, low-cost Maker Pi Pico from Cytron. TL;DR – here’s the Instructable.

In the UK, the Maker Pi Pico is available from The Pi Hut (also as a version without the Pico pre-soldered, but with header sockets). Other distributors around the world can be found at the bottom of this page. The board is very well thought-out and contains a whole raft of features:

  • Access to all Raspberry Pi Pico’s pins on two 20-way pin headers.
  • LED indicators on all GPIO pins.
  • 3x momentary push buttons
  • 1x RGB “NeoPixel-like” LED
  • 1x Piezo buzzer
  • 1x 3.5mm stereo audio jack
  • 1x microSD card slot
  • 1x ESP-01 socket
  • 6x Grove ports

Tony’s experiments are written in CircuitPython and cover using the GPIO pins, reading from the SD card, using a potentiometer on an analog input and using an SSD1306 display to show results from various inputs including a Pimoroni BME680 breakout board.

You can read the Instructable here and you can see one of his demo videos below:

The PicoPicorder – a work-in-progress prototype using a Raspberry Pi Pico and lots of components from Pimoroni and Adafruit!

During March, and for the past week as well, I’ve been working on the latest iteration of my Picorder project. This project, which has been my “go-to project” for the past 9 years (gulp!) is now running from a Raspberry Pi Pico and uses lots and lots of sensors and a touchscreen. You can read all about the project on this page which I will update as I develop and improve the project. Let me know what you think of it so far! All my code is open source and available on GitHub.

Trying out a Raspberry Pi Pico carrier and experimentation board – the Pico 360

It’s always nice when something new arrives in the post and it’s unexpected! Andrew Gale from PocketMoneyTronics has done great things in the past with his subscription-based soldering kits. This time, he has created a carrier board for the Raspberry Pi Pico which helps you to get going on coding with simple components. It is called the Pico 360 and it comes as a solder-it-together-yourself kit.

TL;DR – if you want one, it’s £3.60 (not a typo!) for the kit (not including the Pico itself) and it’s available over on Etsy.

Kit contents

The components are as follows:

  • The PCB
  • 6 red LEDs
  • 1 yellow LED
  • 1 green LED
  • Resistors for all those LEDs
  • 2 momentary buttons/switches
  • 1 piezo buzzer
  • 1 trim potentiometer
  • 2 sets of female header pins (for the Pico to plug into)
  • 1 set of male header pins (to breakout some extra pins)
  • 3 sticky nubs to go on the bottom

The genius move in this case is to include 5 pads which can be attached to with crocodile clips, making this excellent for education where re-use is as important as anything else.

Putting it together

Soldering it together was simple and is best done, in my opinion, in the following order (from lowest height to highest height):

  • Resistors
  • Buttons
  • Potentiometer
  • Buzzer
  • LEDs
  • Male header
  • Female headers

The components are all through-hole, so it should be easy for someone with even “beginner” soldering skills. The only thing I did find was that some of the pads are quite close together. I only had one “oops” and needed a solder sucker. That’s about average for me, anyway!

Once soldered together, I plugged in a Raspberry Pi Pico (which I had already soldered male headers onto).

Example code and video

To my delight, I was able to get all of the included components working straight-off-the-bat by using CircuitPython (which happened to be loaded onto the Pico). My code is here on GitHub as a Gist and you can see the code in action in the video below. If you want a MicroPython demo program, you can find that on Andrew’s website.

Summary and recommendation

This is a great idea for education, especially, and for beginner hobbyists just getting started with the Pico. There are enough components to keep the ideas flowing, and it’s a breeze to solder together. The soldering might put off some educators, of course, but I daresay it will be popular anyway. Who knows? There could be enough demand to do a surface-mount pre-assembled version…

Either way, great job, Andrew! This comes highly recommended!

More information

Andrew has written about the kit over on his website.

Buying the kit

The kit is available for an impressive £3.60 over on Etsy.