Consumer electronics aimed at young children tend to be quite janky and cheap-looking, and they often have to be to survive the extreme stress-testing normal use in this situation. You could buy a higher quality item intended for normal use, but this carries the risk of burning a hole in the pockets of the parents. To thread the needle on this dilemma for a child’s audiobook player, [Turi] built the Grimmboy for a relative of his.

Taking its name from the Brothers Grimm, the player is able of playing a number of children’s stories and fables in multiple languages, with each physically represented by a small cassette tape likeness with an RFID tag hidden in each one. A tape can be selected and placed in the player, and the Arduino at the center of it will recognize the tag and play the corresponding MP3 file stored locally on an SD card. There are simple controls and all the circuitry to support its lithium battery as well. All of the source code that [Turi] used to build this is available on the project’s GitHub page.

This was also featured at the Arudino blog as well, and we actually featured a similar project a while ago with a slightly different spin. Both are based on ideas from Tonuino, an open source project aimed at turning Arduinos into MP3 players. If you’re looking to build something with a few more features, though, take a look at this custom build based on the RP2040 microcontroller instead.

We are continuously inspired by our readers which is why we share what we love, and that inspiration flows both ways. [jetpilot305] connected a Rothult unit to the Arduino IDE in response to Ripping up a Rothult. Consider us flattered. There are several factors at play here. One, the Arduino banner covers a lot of programmable hardware, and it is a powerful tool in a hardware hacker’s belt. Two, someone saw a tool they wanted to control and made it happen. Three, it’s a piece of (minimal) security hardware, but who knows where that can scale. The secure is made accessible.

The Github upload instructions are illustrated, and you know we appreciate documentation. There are a couple of tables for the controller pins and header for your convenience. You will be compiling your sketch in Arduino’s IDE, but uploading through ST-Link across some wires you will have to solder. We are in advanced territory now, but keep this inspiration train going and drop us a tip to share something you make with this miniature deadbolt.

Locks and security are our bread and butter, so enjoy some physical key appreciation and digital lock love.

With events of all sizes on hold and live sports mostly up in the air, it’s a great time to think of new ways to entertain ourselves within our local circles. Bonus points if the activity involves running around outside, and/or secretly doubles as a team-building exercise, like [KarelBousson]’s modernized version of Capture the Flag.

Much like the original, the point of this game is to capture the case and keep it for as long as possible before the other team steals it away. Here, the approach is much more scientific: the box knows exactly who has it and for how long, and the teams get points based on the time the case spends in any player’s possession.

Each player carries an RFID tag to distinguish them from each other. Inside the case is an Arduino Mega with a LoRa shield and a GPS unit. Whenever the game is afoot, the case communicates its position to an external Raspi running the game server.

If you haven’t met LoRa yet, check out this seven-part introductory tutorial.

Seating charts at weddings and other formal events are usually handled by small cards at each table, but Gabrielle Martinfortier had other plans. 

For her big event, she along with help from her now-husband and friends constructed a seating arrangement on a 3’ x 4’ wood canvas, equipped with a 7” TFT display and an RFID reader. An Arduino Mega serves as the brains of the device, taking advantage of its expanded IO capabilities to control an LED assembly over each table on the chart.

Wedding guests simply had to present the card they received with the invitation, then their proper table was lit. As seen in the video below, this eliminated seating confusion, and provided a bit of extra entertainment for those involved. 

I wanted to make something special for my wedding tables chart, and I thought this was a good way of making it personal, as it reflects my love (addiction) for electronic projects.

So the plan was to make a big wood panel with the plan of the room on it, including, of course, the tables and their names (they are plant names, in French). The guests received a card with an RFID sticker on it along with their invitation. On the back of the card was written (in French) something like “This card is of great importance, keep it safe and carry it on you at the wedding.” I didn’t want them to know what it was for until the wedding.

The chart has several elements  a TFT display, an RFID reader, a green LED and a red LED, a push button and one strip of 3 LEDs for each table. When the RFID tags are scanned, the green LED turns on if it is recognized, and a personalized message is displayed on the screen, including the name of the table where the guest is seated. In addition, the LED strip associated with the table is turned on, shedding light on the table on the room’s plan. If the card is misread or unrecognized, the red LED is turned on with an “access denied” message on the screen. The button is for those who did not succeed in not losing or forgetting the card. It displays a message on the screen, asking them to go to the bar and say something like “I am not reliable,” in exchange of which they get a backup chart to find their seat.

I changed a few things along the way: I wanted to paint the wood panel but changed my mind because I was scared I’d make a mess and have to start over with a new panel. Since I have a circuit machine I decided to make the writings and drawings with vinyl.

I also had a 20×04 character LCD screen in the beginning, but I upgraded to a 7″ TFT screen because it’s bigger and not as limiting in terms of message length.

As seen here, “Annaane!” has come up with what could form the guts of a very interesting escape room puzzle. 

Her build features four RFID card readers, which cause an Arduino Uno to release a door lock or other device via a 5V relay, only when the corresponding tags are arranged correctly.

From the looks of the video below, the design is very much a prototype, but could easily be morphed into an arrangement to frustrate and entertain participants. As noted, the project uses all but the TX and RX pins on the Uno, but this could be expanded by using a Mega or an I2C port expander. 

Code for the system can be found on GitHub.

If you’re the kind of person who has friends, and/or leaves the confines of the basement from time to time, we hear that these “Escape Rooms” are all the rage. Basically you get locked into a room with a couple other people and have to solve various problems and puzzles until you’ve finally made enough progress that they let you out. Which actually sounds a lot like the working conditions here at Hackaday HQ, except they occasionally slip some pizza rolls under the door for us which is nice.

Whichever side you find yourself on in one of these lighthearted hostage situations, knowledge of this multi-tag RFID lock created by [Annaane] may come in handy. By connecting multiple MFRC522 RFID readers to an Arduino Uno, she’s come up with a method of triggering a device (like an electronic door lock) only when the appropriate combination of RFID tags have been arranged. With a little imagination, this allows for some very complex puzzle scenarios which are sure to keep your prisoners enthralled until you can lower the lotion down to them.

Her code allows you to configure the type and number of RFID cards required to trigger one of the Arduino’s digital pins, which usually would be connected to a relay to fire off whatever device you want. The Arduino sketch is also setup to give “hints” to the player by way of a status LED: fast blinking let’s you know the tag scanned is wrong, and slow blinking means you don’t have enough scanned in yet.

The video after the break shows some highlights of the build, as well as a quick demonstration of how both the RFID “combination” and manual override can be used to trigger the attached relay.

Hackers do love RFID. Using them for physical access control is a fairly common project around these parts, and we’ve even seen similar setups for the digital realm.

Ever wanted to feel like one of those movie hackers from the late 90s? Yes, your basement’s full of overclocked Linux rigs and you’ve made sure all your terminal windows are set to green text on a black background, but that’s not always enough. What you need is an RFID tag that unlocks your PC when you touch the reader with your RFID card. Only then may you resume blasting away at your many keyboards in your valiant attempts to hack the mainframe.

[Luke] brings us this build, having wanted an easier way to log in quickly without foregoing basic security. Seeing as an RC522 RFID reader was already on hand, this became the basis for the project. The reader is laced up with a Sparkfun Pro Micro Arduino clone, with both devices serendipitously running on 3.3V, obviating the need for any level shifters. Code is simple, based on the existing Arduino RC522 library. Upon a successful scan of the correct tag, the Arduino acts as a HID keyboard and types the user’s password into the computer along with a carriage return, unlocking the machine. Simple!

Overall, it’s a tidy build that achieves what [Luke] set out to do. It’s something that could be readily replicated with a handful of parts and a day’s work. If you’re interested in the underlying specifics, we’ve discussed turning Arduinos into USB keyboards before.

You’d think that with as many sick people as there are in the world, it wouldn’t be too difficult for a doctor in training to get practice. It’s easy to get experience treating common complaints like colds and the flu, but it might take the young doctor a while to run across a dissecting abdominal aortic aneurysm, and that won’t be the time for on the job training.

Enter the SP, or standardized patient – people trained to deliver information to medical students to simulate a particular case. There’s a problem with SPs, though. While it’s easy enough to coach someone to deliver an oral history reflecting a medical condition, the student eventually needs to examine the SP, which will reveal none of the signs and symptoms associated with the simulated case. To remedy this, [Chris Sanders] and [J Scott Christianson] from the University of Missouri developed an open-source RFID stethoscope to simulate patient findings.

This is one of those “why didn’t I think of that?” ideas. A cheap stethoscope is fitted with an Arduino, and RFID reader, and a small audio board. RFID tags are placed at diagnostic points over an SP’s chest and abdomen. When the stethoscope is placed over a tag, a specific sound file is fetched from an SD card and played over earbuds. The student doesn’t have to ask, “What am I hearing?” anymore – the actual sound of bruits or borborygmi are heard.

We can easily see expanding this system – RFID tags that trigger a faux ultrasound machine to display diagnostic images, or tiny OLED screens displaying tagged images into an otoscope. A good place to start expanding this idea might be this digital stethoscope recorder and analyzer.

Give kids some responsible and challenging tasks, and you’d be surprised at the results. The “Anything Goes” exhibit at the National Museum in Warsaw was aimed as a museological and educational experiment. A group of 69 children aged 6–14 was divided into teams responsible for preparing the main temporary exhibition at the museum. Over six months, they worked on preparing the exhibition during weekly four-hour meetings. They prepared scripts, provided ideas for multimedia presentations, and curated almost 300 works for display. One of those was [Robert Mordzon]’s Giant Interactive Crossword.

The build is in two parts. The letter tiles, which have embedded RFID tags, obviously look like the easiest part of the build. The table, looking at the video (after the break), probably needed a lot more effort and labour. It is built in two halves to make construction easier. There are a 130 boxes that need to be filled in with the right letters to complete the crossword. Each box contains a bunch of electronics consisting of an Arduino Nano, a RFID Reader and a bunch of sixteen WS2812B LEDs, all assembled on a custom PCB. Do the math, and you’ll figure out that there’s 2080 LEDs, each capable of sipping 60 mA at full brightness. That’s a total current requirement of almost 125 amps at 5 V. Add in all the Arduino’s, and [Robert] needed a beefy 750 W of power, supplied via four switch mode power supplies.

Each Arduino Nano is a slave on the I²C bus. The I²C master is an Arduino Mega 2560, which in turn communicates with a computer over serial. When a box is empty, the LEDs are dim, when a wrong letter is placed, they turn Red, and when the right letter is placed, they turn Green. If a word gets completed, a special word animation is played. This information is also passed on to the computer, which then projects an animation related to the word on a giant wall screen. Upon the crossword getting completed, the table erupts in to a sound (via the computer) and light “disco” show and also reveals the main motto of this section of the exhibit – “Playing the Hero”.