A Four-Year-Old Event Badge Makes An Environmental Sensor

By now we’re all used to the requirements imposed by the pandemic, of social distancing and wearing masks indoors. But as [polyfloyd] and the rest of the board at Bitlair hackerspace in Amersfoort in the Netherlands were concerned, there are still risk factors to consider when inside a building.  Without fresh air the concentration of virus-bearing droplets can increase, and the best way they could think of to monitor this was to install a set of CO2 sensors. To run them they didn’t need to buy any new hardware, instead they turned to a set of event badges, from 2017s SHA hacker camp.

This badge sported an ESP32 module with an e-ink screen, and of most interest for this project it still has a supported software platform and comes with a handy expansion connector on the rear. The commonly-available MH-Z19 infra-red CO2 sensor and BME280 humidity sensor fit on a PCB that follows the shape of the badge with a protrusion at the top on which they appear as an integrated unit. Processing those readings is a MicroPython badge app that issues warnings via MQTT and plots a CO2 graph on the screen. Everything is available, both the hardware in a GitHub repository and the software as a badge.team app.

We applaud anyone who makes use of an event badge for a project, and especially so for using one years after the event. The SHA badge and its descendants are uniquely suited to this through their well-supported platform, so if you have one in a drawer we’d urge you to pull it out and give it a try.

Plenty Of LEDs And Useful Too: The 2025 DORS/CLUC Badge

It’s always nice to see new developments in the world of electronic badges, and while there are events and badge teams pushing the technological envelope there’s still plenty of scope for innovation without too many exotic parts. This year’s DORS/CLUC open source conference in Croatia has just such a badge, with a large alphanumeric LED display as well as USB and an NFC reader. During the conference it displayed the user’s name and could be used in an NFC-based game, but it’s also designed to be used as a general purpose notification device afterwards.

The write-up is familiar to anyone who has been involved with badge production, a tale of long soldering sessions as missing components had to be added later, and of last minute firmware flashing. The heart of the machine is an STM32L073, with an IS31FL3731 LED matrix driver chip and an ST25R3916 for the NFC. All the files can be found in a GitLab repo, and there’s a video below the break showing it all in action.

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Hackaday Europe 2025: Speaker Schedule And Official Event Page

Hackaday Europe 2025 is just days away, and we’ve got the finalized speaker schedule hot off the digital press. We’re also pleased to announce that the event page is now officially live, where you can find all the vital information about the weekend’s festivities in one place.

Whether you’ll be joining the fun in Berlin, or watching the live stream from home, we’ve got a fantastic lineup of speakers this year who are eager to tell us all about the projects that have been keeping them up at night recently:

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Clever PCBs Straighten Out The Supercon SAO Badge

When we decided that Simple Add-Ons (SAOs) would be the focus of Supercon 2024, it was clear the badge would need to feature more than just one or two of the requisite connectors. We finally settled on six ports, but figuring out the geometry of getting all those ports on the badge in such a way that the SAOs wouldn’t hit each other was a bit tricky. In early concept drawings the badge was just a big rectangle with the ports along the top, but it was too ugly.

In the end we went with a somewhat organic design — an electronic “flower” with the radially arranged SAOs forming the petals, but this meant that that none of the SAOs were in the traditional vertical orientation. Luckily, [Adrian Studer] designed a couple of PCBs that not only resolve this issue, but add a seventh SAO port for good measure.

In the project repository you’ll find two PCB designs. The first, “SAO Up” is essentially a little arm that turns the SAO port 90 degrees. This doesn’t exactly get them vertical, in fact, whether or not the new orientation is actually an improvement for the top two SAOs is perhaps debatable. But it definitely helps on the lower SAOs, which are essentially upside down in their original configuration.

The real star of the show is “SAO Bridge”, a wavy board that connects across the two midline SAO ports on the Supercon badge and turns it into a set of three (nearly) horizontal connectors across the front. The center port is particularly helpful in that it gives you a place to put unusually wide SAOs.

As a reminder the Supercon SAO badge, and the winners of the 2024 SAO Contest, will be making the trip across the pond for Hackaday Europe in just a few months. That means you’ve still got plenty of time to have a few of these CERN-OHL-P licensed boards made up.

A New Life For A Conference Badge, Weighing Bees

We love electronic conference badges here at Hackaday, but it’s undeniable that many of them end up gathering dust after the event. Most of them are usable as development boards though, so it’s nice to see them appear in projects from time to time. [Benjamin Blundell] has a good one, he’s using an EMF Camp 2014 badge to power a set of load cells in a bee scale.

Not being skilled in the art of apiary here at Hackaday we’re thankful for his explanation. Beekeepers weigh their hives as a means of gauging their occupancy, and the scale for this purpose has a few application specific features. The EMF 2014 badge (known as the TiLDA MKe) meanwhile is an Arduino Due compatible ARM Cortex M0 board with an LCD display, making it perfect for the job. He devotes quite some time to describing the load cells, mounting them on extrusion, and calibration, all of which should be of use to anyone making a scale.

The software for the badge is an odd mix of Arduino and FreeRTOS, and he takes one of the stock apps and modifies it for the scale. It’s very much a badge of its era, being programmable but not with a built-in interpreter for MicroPython or similar. You can see the whole project at work in the video below the break.

If you’ve not seen a TiLDA MKe before, we wrote about it when it was released.

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FREE-WILi Turns DC32 Badge Into Hardware Dev Tool

With few exceptions, electronic event badges are often all but forgotten as soon as the attendee gets back home. They’re a fun novelty for the two or three days they’re expected to be worn, but after that, they end up getting tossed in a drawer (or worse.) As you might imagine, this can be a somewhat depressing thought thought for the folks who design and build these badges.

But thanks to a new firmware released by the FREE-WILi project, at least one badge is going to get a shot at having a second life. When loaded onto the RP2350-powered DEF CON 32 badge, the device is turned into a handy hardware hacking multi-tool. By navigating through a graphical interface, users will be able to control the badge’s GPIO pins, communicate over I2C, receive and transmit via infrared, and more. We’re particularly interested in the project’s claims that the combination of their firmware and the DC32 badge create an ideal platform for testing and debugging Simple Add-Ons (SAOs).

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Supercon 2024 Flower SAO Badge Redrawing In KiCad

Out of curiosity, I redrew the Supercon Vectorscope badge schematics in KiCad last year. As you might suspect, going from PCB to schematic is opposite to the normal design flow of KiCad and most other PCB design tools. As a result, the schematics and PCB of the Vectorscope project were not really linked. I decided to try it again this year, but with the added goal of making a complete KiCad project. As usual, [Voja] provided a well drawn schematic diagram in PDF and CorelDRAW formats, and a PCB design using Altium’s Circuit Maker format (CSPcbDoc file). And for reference, this year I’m using KiCad v8 versus v7 last year.

Importing into KiCad

This went smoothly. KiCad imports Altium files, as I discovered last year. Converting the graphic lines to traces was easier than before, since the graphical lines are deleted in the conversion process. There was a file organizational quirk, however. I made a new, empty project and imported the Circuit Maker PCB file. It wasn’t obvious at first, but the importing action didn’t make use the new project I had just made. Instead, it created a completely new project in the directory holding the imported Circuit Maker file. This caused a lot of head scratching when I was editing the symbol and footprint library table files, and couldn’t figure out why my edits weren’t being seen by KiCad.  I’m not sure what the logic of this is, was an easy fix once you know what’s going on. I simply copied everything from the imported project and pasted it in my new, empty project. Continue reading “Supercon 2024 Flower SAO Badge Redrawing In KiCad”