Automated Shusher Keeps Conference Loudmouths In Line

Few things are more annoying than being at a conference and having an inconsiderate group conducting a vociferous sidebar that drowns out the speaker. More annoying still is the inevitable shushing; nobody likes being either the shusher or the shushed. So why not take the humans out of the loop and automate the chore of keeping the peace?

Such was the challenge presented to [BotBerg] before a recent conference, who came up with this automated shusher (translation) on short notice. The build is based on the Arduino Nano 33 BLE Sense Deck, a sensor-rich dev board that’s perhaps a little overkill for the job, but hey — you roll with what you’ve got. The board’s MEMS microphone is the sensor used here, which measures the ambient sound pressure level multiple times per second. When the background noise exceeds a potentiometer-set threshold, an MP3 player is triggered to play a sound clip entreating the offenders to pipe down. The whole thing is housed in a playful 3D-printed enclosure shaped like a mouth, which should be sufficient reminder alone to keep yours shut.

This was a quick-and-dirty prototype, of course, and probably could use some refinement. Given the behavior we’ve witnessed at some conferences, we’d say hooking it up to a Nerf turret gun would be a justifiable escalation.

Annoying Cicada Magnet Is Nonetheless Authentic

We’ve all heard of those chirper devices that randomly make annoying noises for no other reason than sending people insane. This project from [Kousuke Saito] brings altogether more art to this idea, while still being quite annoying indeed.

The build is essentially a replica cicada. [Saito] was inspired to build the device as the sounds of the insect remind him fondly of the summer. His design consists of a 3D-printed housing that roughly approximates something like a cicada, with two wings attached to a central body. In this case, the layer lines of the 3D print actually added to the realism of the ersatz insect The housing is nicely painted to serve as an adequate simulacra to those who aren’t up on their entomology.

Inside, there’s an ATTiny 85 paired with an MP3 playback module and a small speaker. It’s charged with reproducing the noise of various cicadas. It’s setup with an ingenious mechanism to switch it on. There are magnets installed in the base which allow it to stick to metallic objects. There’s also a switch in the bottom of the device. When it magnetically attaches to a surface, that switch is depressed, and the cicada starts playing, well… cicada noises. [Saito] notes that a patent has been secured for the idea.

We’ve seen other cicada-themed projects before, astoundingly. Video after the break.

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3d printed tiny gym in a box with mirror and led strip lighting

Get Pumped For This Miniature Gym

[Duncan McIntyre] lives in the UK but participated in a secret Santa gift exchange for his Dutch friends’ Sinterklaas celebration. In traditional maker fashion, [Duncan] went overboard and created a miniature gym gift box, complete with flashing lights, music and a motorized lid.

[Duncan] used [TanyaAkinora]’s 3D printed tiny gym to outfit the box with tiny equipment, with a tiny mirror added to round out the tiny room. An ATmega328P was used as the main microcontroller to drive the MP3 player module and A4988 stepper motor controller. The stepper motor was attached to a drawer slide via a GT2 timing belt and pulley to actuate the lid. Power is provided through an 18V, 2A power supply with an LM7805 providing power to the ATmega328P and supporting logical elements. As an extra flourish, [Duncan] added some hardware audio signal peak detection, fed from the speaker output, which was then sampled by the ATmega328P to be able to flash the lights in time with the playing music. A micro switch detects when the front miniature door is opened to begin the sequence of lights, song and lid opening.

[Duncan] provides source on GitHub for those curious about the Arduino code and schematics. We’re fans of miniature pieces of ephemera and we’ve featured projects ranging from tiny 3D printed tiny escalators to tiny arcade cabinets.

Video after the break!

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Kids’ Jukebox Based On Arduino With RFID

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.

The speaker PCB inside of the speaker, with a flash chip ZIF holder soldered to the SPI flash pads on the PCB

Bluetooth Speaker Domesticated Through Firmware Mod

This might sound like a familiar problem – you get a Bluetooth speaker, and it sounds nice, but it also emits all kinds of weird sounds every now and then. [Oleg Kutkov] got himself a Sven PS460 speaker with FM radio functionality, but didn’t like that the “power on” sound was persistently loud with no respect for the volume setting, and the low battery notification sounds were bothersome. So, he disassembled the speaker, located a flash chip next to the processor, and started hacking.

Using a TL866 and minipro software, he dumped the firmware, and started probing it with binwalk. The default set of options didn’t show anything interesting, but he decided to look for sound file signatures specifically, and successfully found a collection of MP3 files! Proper extraction of these was a bit tricky, but he figured out how to get them out, and loaded the entire assortment into Audacity.

From there, he decided to merely make the annoying sounds quieter – negating the “no respect for the volume setting” aspect somewhat. After he exported the sound pack out of Audacity, the file became noticeably smaller, so he zero-padded it, and finally inserted it back into the firmware. Testing revealed that it worked just as intended! As a bonus, he replaced the “battery low” indicator sound with something that most of us would appreciate. Check out the demo video at the end of his write-up.

Domesticating your Bluetooth speakers tends to be called for. If you can’t do that for whatever reason, you can rebuild them into an audio receiver – or perhaps, build your own Bluetooth speakers, with aesthetics included and annoyance omitted from the start.

picture of finished mp3 player that uses a cartridge to select songs

An MP3 Player That Gives Off Nintendo Vibez

We’re definitely pretty fond of the DIY MP3 players here at Hackaday, but we don’t think we’ve seen one like CartridgeMP3 from [jpet26] before.

All the electrical components are what we’ve come to expect. [jpet26] uses the popular VS1053 decoder to read MP3 files stored on an SD card. He also includes a potentiometer for adjusting volume, a USB C port for power and programming, a headphone jack for the audio output, a general-purpose status LED, and an on/off switch.

But what really caught our attention is the form factor [jpet26] selected for his MP3 player. Though the MP3 files are stored on an SD card, he uses a cartridge interface, similar to that of a Nintendo 64 or Game Boy of yesteryear, to choose which MP3 to play from the SD card. The cartridge interface is tied to a few GPIO pins and by reading the status of each pin, the device determines which MP3 to select.

You could say that the cartridge is a little unnecessary, and we wouldn’t argue with you. The cartridge doesn’t actually store the MP3 files, the SD card does. It might make a bit more sense if the cartridge housed the SD card itself with a few select MP3s stored on the card. That would be a quirky way of sharing your favorite playlists with your friends. So, yeah some clumsy handshaking there, but who isn’t guilty of that from time to time? We like it and thought you might appreciate it as well.

Cool MP3 player, [jpet26]! May we suggest a speaker for V2? And maybe some flex cables.

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Daft Punk Word Clock Goes Stronger And Faster

What would you call a word clock that doesn’t tell time? The concept of a word clock is that all the words needed to be used are already there and then just selected. [Ben Combee] realized there were only 18 unique words to make up the song “Harder Faster Better Stronger” and with an extra PyBadge from Supercon 2021 on hand, it seems obvious to make a musical word clock of sorts.

The PyBadge is a 120 MHz ATSAMD51 based board with a screen, buttons, and a case that he 3d printed. To get reasonable sound quality while still fitting with the 2MB of flash storage on the device, MP3 compression was chosen. Since there was only one speaker, it was mixed down to mono and a lower bitrate, getting the size down to just 880KB. The mp3 is processed by the audiomp3 module in circuitpython with the volume level being sent to five NeoPixels to act as a VU. Getting the timing correct was the hardest part as the lyrics needed to be separated out and the timing figured out. Using Audacity’s label track feature, he had all the words tagged in the track and could export it into a format that could be massaged into a python friendly format.

The music and the text cues becoming desynchronized became a larger issue as the file plays. Increasing the MP3 buffer helped but the real trick was to peek inside the music decoder and figure out how many samples had been decoded and cue the words based on that, rather than the time since it wasn’t as accurate. All the code and files are up on his page if you feel the need to make your own. If you’re sticking with Daft Punk, make sure to have your helmet ready when you rock. Though based on this summary of the compressibility of pop songs, there are a few other songs with a small enough number of unique words that they too could get the word clock treatment. Video after the break.

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