Prototyping new ideas can be a lot of fun, but putting new projects in a durable enclosure can be a difficulty. This is especially the case when the user of this product is one of the most destructive forces in nature: A toddler! This is the circumstance that [blue blade] found himself in when he wanted to build a durable MP3 player for his grandson, and you can see the results of his work below the break.
The hardware is simple: A 16850 lithium-ion battery powers an MP3 Decoder/Amplifier module that plays MP3s stored on a Micro SD card. A speaker, power switch, and micro USB powered battery charger complete the build. What stands out most is the enclosure. Why?
When children are involved, durability isn’t a matter of product lifetime, it’s also a matter of safety. Items that are easily broken aren’t just useless, they can be dangerous. With this in mind, [blue blade] built a brightly colored enclosure with extra thick walls joined by metal bolts. Externally, a rounded cover bolts over the charger connector and Micro SD card slot. The only other protrusion is a lighted rocker switch for powering the MP3 player on and off.
Though kids today have an incredible knack for figuring out modern phones and tablets, there’s still something to be said for offering a simple physical user interface for little hands. To that end, [Martin Hierholzer] has put together a whimsical jukebox that his two year old daughter can use to listen to her favorite songs. With just a few simple buttons, no display to read, and the ability to stop and start songs using RFID tags embedded into 3D printed figures, it’s a perfect interface for tiny humans just getting the hang of interacting with technology.
While the Raspberry Pi might have been the more obvious choice to base this project around, [Martin] decided to go the ESP32 route for improved energy efficiency. The popular microcontroller is more than powerful enough to play MP3s, and its integrated WiFi connectivity allows the player to download new tracks from the network occasionally. He added a micro SD slot to provide some mass storage, a PCM5102 I2S DAC with a PAM8403 amplifier to handle the audio side of things, and a MFRC522 RFID receiver that can pick up tags placed on the top of the player. Power is provided by parts salvaged from a USB battery bank, and everything is housed on a custom PCB.
The relatively low power requirements of the ESP32 means the jukebox can keep the party going for many hours (perhaps even days) when in active use. When the RFID token is removed and there are no songs to play, some clever coding kicks the chip into low-power mode to greatly extend the player’s standby time. [Martin] says it can sleep for months without having to be recharged, and considering some of the impressive feats of battery-sipping we’ve previously seen from the ESP32, we don’t doubt it.
Even if you don’t have any young music lovers at home, the documentation [Martin] has put together for this project is absolutely worth a look. Whether its how he configures the server side to push songs and firmware updates to the player, how he wrangled the ESP32’s Ultra-Low Power coprocessor (ULP), or the woodworking tips used to produce the charming enclosure, you’re sure to pick up a trick or two.
This article was meant to be finished up before Christmas, so it’ll be a little late whenever you’re reading it to go and prepare this for the holiday. Regardless, if, like me, should you ever be on the lookout for something to give a toddler nephew or relative, it could be worth it to look into your neglected old parts shelves. In my case, what caught my eye was a 9-year-old AMD laptop catching dust that could be better repurposed in the tiny hands of a kid eager to play video games.
The main issues here are finding a decent selection of appropriate games and streamling the whole experience so that it’s easy to use for a not-yet-hacker, all the while keeping the system secure and child-friendly. And doing it all on a budget.
This is a tall order, and requirements will be as individual as children are, of course, but I hope that my experience and considerations will help guide you if you’re in a similar boat.
When designing this custom MP3 player for his grandson, [Luc Brun] ran into a unique problem. He wanted the boy to be able to operate the player on his own, but being only 2½ years old, the user interface would have to be exceedingly straightforward. Too many buttons would just be a distraction, and a display with text would be meaningless at his age.
In the end, [Luc] came up with a very interesting way of navigating through directories full of MP3 files using a few push buttons and a ring of WS2812 LEDs. The color of the LEDs indicate which directory or category is currently being selected: spoken nursery rhymes are red, music is orange, nature sounds are yellow, and so on. The number of LEDs lit indicate which file is selected, so in other words, three orange LEDs will indicate the third music track.
At his grandson’s age, we imagine at least a little bit of him navigating through this system is just luck. But as he gets older, he’ll start to form more solid connections between what he’s hearing and the color and number of the LEDs. So not only is this interface a way to help him operate the device himself, but it may serve as a valuable learning tool in these formative years.
[Ekaggrat Singh Kalsi] submits this interesting printer he built for his daughter to use. He admits that the project started simply out of curiosity about the strange deltesian movement. In this configuration, the X and Z-axis are a delta mechanism while the Y-axis is a regular Cartesian bed on rails. There’s not a load of advantages to this movement, but it is really neat.
Eventually, he had a hammer in search of a nail and decided to make the printer easy enough for his daughter to use. To this end, he added a few kid-friendly modifications. The unheated bed is removable and snaps in and out of place with magnets. Considerable attention was paid to the filament loading and unloading to make it easy for small hands to perform the process. This was accomplished through a lever based latch mechanism.
As you can see in the video after the break, the project was a success, and his daughter is growing up with access to her very own 3D printer. If you’re curious abou the classic delta robot, check out this golf ball sorter.
“Kid-friendly table saw” seems like either a contradiction, a fool’s errand, or a lawsuit waiting to happen; but this wooden table saw for kids actually fits the bill and shows off some incredible workmanship and attention to detail as well. The project works by using not a saw blade, but a nibbler attached to a power drill embedded inside.
Unsurprisingly, the key to making a “table saw” more kid-friendly was to remove the saw part. The nibbler will cut just about any material thinner than 3 mm, and it’s impossible for a child’s finger to fit inside it. The tool is still intended for supervised use, of course, but the best defense is defense in depth.
The workmanship on the child-sized “table saw” is beautiful, with even the cutting fence and power switch replicated. It may not contain a saw, but it works in a manner much like the real thing. The cutting action itself is done by an economical nibbler attachment, which is a small tool with a slot into which material is inserted. Inside the slot, a notched bar moves up and down, taking a small bite of any material with every stroke. Embedding this into the table allows for saw-like cutting of materials such as cardboard and thin wood.
The image gallery is embedded below and shows plenty of details about the build process and design, along with some super happy looking kids.