DIY Pocket MP3 Player

When [Neutrino-1] saw DFRobot’s DFPlayer module, he decided he wanted to make his own retro MP3 player. This tiny module comes packed with a ton of interesting capabilities such as EQ adjustment, volume control, and a 3 watt amplifier amongst other things. It can even play ads in between songs, should you want such a thing.

Controlling the DFPlayer module is easy using serial commands from a microcontroller, making it a convenient subsystem in bigger projects, and a potential alternative to the popular VLSI chips or the hard to come by WT2003S IC. [Neutrino-1] does a good job walking readers through the build making it fairly easy to remix, reuse, and reshare.

With the hardware sorted, all you’ve got to do is flash the firmware and load up an SD card with some MP3s. There’s even a small Python GUI to help you get your new player up and running. [Neutrino-1] also introduces users to the U8g2 display library which he says is a bit more feature-rich than the common Adafruit SSD1306 library. Great job [Neutrino-1]!

While you’re here, take a look at some of our other MP3 projects.

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Custom Bluetooth Joystick In A Nunchuk Shell

With the Wii’s unique controller, Nintendo not only provided new gaming experiences to players, but gave hardware hackers a platform for experimentation that’s still going strong. Case in point, this modification of a third party Wii “Nunchuk” by [Giliam de Carpentier] that turns the accessory into a stand-alone wireless controller powered by a ATtiny44A.

Milling a new home for the AVR

It turns out there’s a considerable amount of free space inside the Nunchuk case, so [Giliam] found adding in the new hardware wasn’t nearly as difficult as you might expect. Of course, it helps that the diminutive SMD ATtiny44A and its support hardware are housed on a very neatly milled PCB that attaches to the back of the original board.

Most of the other hardware comes in the form of modular components, like the  Bluetooth transmitter and TP4056 charge controller for the 300 mAh battery. A micro USB charging port is mounted where the original Nunchuk cable entered the case, making the whole thing look very professional.

Even if you aren’t interested in making your own controller, [Giliam] covers many interesting topics in this write-up such as handling different methods of Bluetooth connectivity and various power management techniques to eke out as much life from the relatively small battery as possible. It’s not only a fascinating read, but a great example of what thorough project documentation should look like.

In the past we’ve seen Bluetooth conversions for the Wii Nunchuck, but traditionally they left the original electronics in place. On the other side of the spectrum, we’ve also seen the internals get replaced with something as powerful as the Raspberry Pi Zero.

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DIY Smartwatch Based On ESP8266 Needs Classification

Building your own smartwatch is a fun challenge for the DIY hobbyist. You need to downsize your electronics, work with SMD components, etch your own PCBs and eventually squeeze it all into a cool enclosure. [Igor] has built his own ESP8266-based smartwatch, and even though he calls it a wrist display – we think the result totally sells as a smartwatch.

His design is based on a PCB for a wireless display notifier he designed earlier this year. The design uses the ESP-12E module and features an OLED display, LEDs, tactile switches and an FT232R USB/UART interface. Our beloved TP4056 charging regulator takes care of the Lithium-ion cell and a voltage divider lets the ESP8266’s ADC read back the battery voltage. [Igor] makes his own PCBs using the toner transfer method, and he’s getting impressive results from his hacked laminator.

Together with a hand-made plastic front, everything fits perfectly into the rubber enclosure from a Jelly Watch. A few bits of Lua later, the watch happily connects to a WiFi network and displays its IP configuration. Why wouldn’t this be a watch? Well, it lacks the mandatory RTC, although that’s easy to make up for by polling an NTP time server once in a while. How would our readers classify this well-done DIY build? Let us know in the comments!

$1 Coin Cell Charger

Sure, coin cells usually last a long time — but do you really want to buy new ones and throw the old ones out? The LiR2032 coin cell is a rechargeable lithium battery, for which you can build a charger at around $1.

The 5 minute hack starts with a TP4056 lithium charging circuit, which is a great DIY board designed to charge high-capacity cells at about 1A. Luckily, it is pretty easy to modify the board to charge lower capacity batteries. It’s just a matter of replacing resistor R4, and a little bit of soldering! Continue reading “$1 Coin Cell Charger”