A CO2 Traffic Light On An SAO

November 6, 2024 by Dave Rowntree 12 Comments

[David Bryant] clearly has an awareness of the impact of an excess concentration of CO₂ in the local environment and has designed an SAO board to add a CO₂ traffic light indicator to one of the spare slots on the official Hackaday Supercon 2024 badge.

The part used is the Sensirion SCD40 ‘true’ CO2 sensor, sitting atop an Adafruit rider board. [David] got a leg up on development by creating a simple SAO breakout board, which could have either the male and female connectors fitted, as required. Next, he successfully guessed that the badge would be based around the RP2040 running MicroPython and hooked up an Adafruit Feather RP2040 board to get started on some software to drive the thing. This made hooking up to the official badge an easy job. Since the SAO has only two GPIOs, [David] needed to decode these to drive the three LEDs. There are a few ways to avoid this, but he wanted to relive his earlier EE college years and do it the direct way using a pair of 74HC00 quad NAND gate chips.

We’ve seen a few CO₂ monitors over the years. This sleek little unit is based around the Seeeduino XIAO module and uses an LED ring as an indicator. Proper CO₂ monitors can be a little pricey, and there are fakes out there. Finally, CO₂ is not the only household pollutant; check out this project.

The 2024 Hackaday Supercon SAO Badge Reveal

October 22, 2024 by Elliot Williams 25 Comments

We’ve been hinting at it for a few months now, running a series of articles on SAOs, then a Supercon Add-On Challenge. We even let on that the badge would have space for multiple SAOs this year, but would you believe six?

Way back in 2017ish, Hackaday’s own [Brian Benchoff] and the [AND!XOR] crew thought it would be funny and useful to create a “standard” for adding small custom PCB art-badges onto bigger conference badges. The idea was to keep it quick and dirty, uncomplicated and hacky, and the “Shitty” Add On was born. The badge community took to this like wildfire. While the community has moved on from the fecal humor, whether you call these little badgelets “SAOs”, “Simple Add-Ons”, or even “Supercon-8 Add Ons”, there’s something here for everyone. So if you’ve already got some SAOs in a drawer, bring them to this year’s Supercon and show them off!

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An SAO For Hams

October 21, 2024 by Al Williams 18 Comments

Generally speaking, the Hackaday Supercon badge will always have a place for SAO (rebranded as “Supercon add-ons”), and that makes sense. We did originate them, after all. This year, though, we’ve gone all in on SAO, and, in particular, we’ve asked to see more SAOs with communication capabilities. The standard has always had an I2C bus, but few people use them. I decided I wanted to set an example and cook up a badge for Supercon. Was it hard? Yes and no. I’ll share with you a little about the board’s genesis and the issues I found. At the end, I’ll make you a special offer, if you are going to Supercon.

The Idea

The front of the SAOGNR — the SAO connector is, of course, on the back

I’ve been a ham radio operator for a very long time. In fact, July was my 47th anniversary in the radio hobby. Well, that’s not true. It was my 47th year with a license. I had been listening to shortwave long before then. So, I wanted to do something with Morse code. You don’t have to know Morse code to get a license these days, but a lot of hams enjoy it.

I set out to do a simple board that would play some Morse code messages. But that’s just another blinking light LED with a buzzer on it, too. So, naturally, I decided it would also provide Morse code output for the I2C host. That is, the SAO could be used to convert ASCII to Morse code. Sounds simple, right? Sure.

Getting Started

I wanted to use a Raspberry Pi Pico but didn’t want to violate the SAO size requirements. Luckily, there’s an RP2040-Zero module that is quite tiny and looks more or less like a normal Pico. The two big differences are plusses: they have a reset button, and instead of a normal LED, they have a WS2812b-style LED.

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Breaking News: 2024 Supercon SAO Contest Deadline Extended

October 15, 2024 by Elliot Williams 1 Comment

More than a couple folks have written us saying that their entries into the Supercon Add-On Contest got caught up in the Chinese fall holidays. Add to that our tendency to wait until the last minute, and there still more projects out there that we’d like to see. So we’re extending the deadline one more week, until October 22nd.

If you’re just tuning in now, well, you’ve got some catching up to do. Supercon Add-Ons are another step forward in the tradition of renaming the original SAO. One of our favorite resources on the subject comes from prolific SAO designer [Twinkle Twinkie], and you can even download PCB footprints over there on Hackaday.io.

Don’t know why you want to make an SAO? Even if you’re not coming to Supercon this year? Well, our own [Tom Nardi] describes it as a low barrier to entry, full-stack hardware design and production tutorial. Plus, you’ll have something to trade with like-minded hardware nerds at the next con you attend.

We’ve already seen some killer artistic entries, but we want to see yours! We know the time’s tight, but you can still get in a last minute board run if you get started today. And those of you who are sitting at home waiting for boards to arrive, wipe that sweat from your brow. We’ll catch up with you next Tuesday!

A render of an SAO that resembles a Speak 'n Spell.

2024 SAO Contest: Speak, SAO

September 27, 2024 by Kristina Panos 7 Comments

For some of us, the Speak ‘n Spell evokes pleasant memories of childhood as our first computer, along with one of those Merlin things. For others, it’s the ultimate circuit bending victim. For [Jeremy Geppert], they’re all-around good fun and he wanted to immortalize the device in a Simple Add-On (SAO).

This is [Jeremy]’s first board and SAO rolled into one, motivated by both Supercon and the SAO Contest. To start things off, [Jeremy] scaled down the design we all know and love to fit a 128×32 OLED display, and it looks great. The plan is to have the display, an amplified speaker, and a single button for input.

Before committing the board order, [Jeremy] had a brief freak-out about the pin distance as it relates to the window for the OLED display. Luckily, his brother suggested checking things first by printing a 1:1 scale image of the board outline, and laying that over the display.

This is the week it all comes together, as the tiny switches and (regular-size) connectors have arrived, and the boards are due quite soon. Go, [Jeremy], go!

A golden Jolly Wrencher SAO that works as an NFC tag for sharing contact info.

2024 SAO Contest: The Jolly Tagger Is A Golden Way To Share Info

September 19, 2024 by Kristina Panos 16 Comments

For this contest, we’re asking you to come up with the best SAO you can think of that does something cool. What could be cooler than sharing your contact information all over Supercon and beyond with a tap of a Jolly Wrencher? It’s way better than just some sticker, and with the extra solder pad on the back, you can turn it into a pin once the con is over. Contact data can be uploaded over I²C.

An antenna coil PCB trace as generated by a KiCad plugin. — The KiCad-generated coil.

Here, [Phil Weasel] seeks to answer the question of whether one can make a working NFC tag with the M24LR04E IC, using a PCB trace as a coil. If there is an issue, it’s probably going to be that copper plane inside the antenna.

Designing the antenna itself proved fairly easy after checking the datasheet for the internal tuning capacitance (~27.5 pF), verifying the frequency of NFC (~13.56 MHz), and doing the math to find the inductance needed. After confirming everything in LTSpice, [Phil] used a PCB coil calculator and let the KiCad coil generator draw it out.

Did we mention the Jolly Wrencher is backlit by four side-mounted LEDs? Because what’s an SAO without a few blinkenlights?

A Nibble Of Core Memory, In An SAO

September 3, 2024 by Jenny List 15 Comments

Core memory, magnetized memory using tiny magnetic rings suspended on a grid of wires, is now more than five decades obsolete, yet it exerts a fascination for hardware hackers still. Not least [Andy Geppert], who’s made a nibble, four bits of it, complete with interactive LED illumination to show state. Best of all, it’s on a badge Simple Add-On (SAO) for fun and games at your next hacker con.

Aside from it being a fun project, perhaps the most interesting part comes in the GitHub repository, where can be found the schematic for the device. He’s built all the drive and sense circuitry himself rather than finding an old-stock core memory driver chip, which gives those of us who’ve never worked with this stuff the chance to understand how it works. Beyond that it takes input from the Stemma or SAO ports to a GPIO expander, which provides all the lines necessary to drive it all.

To show it in action he’s posted a video which we’ve placed below. If you’re hungry for more, it’s not [Andy]’s first outing into core memory.

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