The 6th Generation iPod Nano was something of a revelation on launch. Packing a color screen, audio hardware, and a rechargable battery into a package no bigger than a large postage stamp remains impressive to this day. They’re now being used in various maker projects for their displays, but if you’re doing so, you might want to think about how you’re going to build a graphical interface. Not to worry – just grab an ESP32 and the right GUI library, and you’re on your way.
The Nano screen uses a MIPI DSI interface, which isn’t the easiest thing to use directly with the ESP32. Instead, a SSD2805 interface chip converts parallel input data to MIPI DSI signals to drive the display. Driving the display is only part of the game, however – you need something to display on it. Combining the LittlevGL GUI library with the screen’s touchpad makes creating a full graphical interface easy.
Hacked screens are something we don’t see as much these days, with the proliferation of display products aimed directly at the maker market. However, it’s always awesome to see a successful hack pulled off well. We’ve seen the display reverse engineered, too – and it certainly wasn’t easy.
[Mike Harrison] produces so much quality content that sometimes excellent material slips through the editorial cracks. This time we noticed that one such lost gem was [Mike]’s reverse engineering of the 6th generation iPod Nano display from 2013, as caught when the also prolific [Greg Davill] used one on a recent board. Despite the march of progress in mobile device displays, small screens which are easy to connect to hobbyist style devices are still typically fairly low quality. It’s easy to find fancier displays as salvage but interfacing with them electrically can be brutal, never mind the reverse engineering required to figure out what signal goes where. Suffice to say you probably won’t find a manufacturer data sheet, and it won’t conveniently speak SPI or I2C.
After a few generations of strange form factor exploration Apple has all but abandoned the stand-alone portable media player market; witness the sole surviving member of that once mighty species, the woefully outdated iPod Touch. Luckily thanks to vibrant sales, replacement parts for the little square sixth generation Nano are still inexpensive and easily available. If only there was a convenient interface this would be a great source of comparatively very high quality displays. Enter [Mike].
This particular display speaks a protocol called DSI over a low voltage differential MIPI interface, which is a common combination which is still used to drive big, rich, modern displays. The specifications are somewhat available…if you’re an employee of a company who is a member of the working group that standardizes them — there are membership discounts for companies with yearly revenue below $250 million, and dues are thousands of dollars a quarter.
Fortunately for us, after some experiments [Mike] figured out enough of the command set and signaling to generate easily reproduced schematics and references for the data packets, checksums, etc. The project page has a smattering of information, but the circuit includes some unusual provisions to adjust signal levels and other goodies so try watching the videos for a great explanation of what’s going on and why. At the time [Mike] was using an FPGA to drive the display and that’s certainly only gotten cheaper and easier, but we suspect that his suggestion about using a fast micro and clever tricks would work well too.
It turns out we made incidental mention of this display when covering [Mike]’s tiny thermal imager but it hasn’t turned up much since them. As always, thanks for the accidental tip [Greg]! We’re waiting to see the final result of your experiments with this.
The current marketplace allows hobbyists to easily find inexpensive, well-documented displays, but what if you wanted to interface with something more complicated, such as the screen on an iPod Nano 6? [Mike] has given us a detailed and insightful video showing his process for reverse engineering a device with little-to-no documentation. Here he covers the initial investigation, where one scours the web in search of any available information. In [Mike’s] example, the display uses an MIPI D-PHY interface, which he has never worked with. He learns that the MIPI Alliance will provide design specs in exchange for a signed NDA (Non-Disclosure Agreement) and a modest $8000 fee. Nice.
[Mike] shows off some serious hardware hackery, tackling some extremely difficult soldering in order to set up a proper test platform. He then demonstrates how to use a rather awesome oscilloscope to better understand the display protocol. We found it fascinating to see the video signals displayed as waveforms, especially when he shows how it is possible to count the individual binary values. The amount of information he uncovers with the oscilloscope is nothing short of amazing, proving these little devices are more complex than they seem.
The 6th generation iPod nano makes a wonderful watch, but something milled out of aluminum doesn’t lend itself to more formal events. [Ted] liked the idea of an iPod nano watch, but wanted to kick things up a notch and fabricate an 18k gold iPod nano. It took 500 hours and $2500 in materials, but we’d say it’s worth it.
The new 18k gold enclosure for the watch was fabricated using the lost wax casting method. First, all the electronics and buttons were removed from the iPod, then a negative mold was made in silicone rubber. A positive wax mold was made with the silicon mold, and finally another negative mold – this time in plaster – was made by vaporizing the positive wax mold in a furnace.
[Ted] used two one-ounce coins as the source of gold for his nano enclosure, spun into the plaster mold. From there, it’s just a simple but tedious matter of cutting the sprues off, shaping, filing, buffing, and polishing. With a new leather strap, the iPod is reassembled in its new enclosure.
Wonderful work, and amazingly impressive from someone who doesn’t consider himself a jeweler.
[Hyeinkali’s] iPod Nano looks right at home on the dashboard of his 2001 Honda Accord. He got rid of the simple LCD clock and the buttons that were used to set it. The hack holds the iPod securely in place, but it remains easy to remove and take with you.
He started by popping out the bezel that holds the clock module and hazard light button in place. The original display was about the same width as the Nano, but he wasn’t interested in mounting the mp3 player under the dash. Since he needed to be able to take it with him to sync his music library he made a space near the bottom of the bezel to accept the connector end of the USB cable while keeping the device accessible. After connecting the other end to power he covered the hole in the bezel with mesh and put everything back together. We’re not sure if audio is piped into the car stereo via a cable or through Bluetooth, but it does feed to the head unit.
OK guys, I can finally announce all of the prizes for the Hack-A-Day Design Challenge! I’ve been waiting to get things in hand before announcing them all – Everything’s arrived, and it’s a pretty sweet haul.
Fabienne’s Hack-A-Day iPod Nano
MAKE Daisy mp3 player kit
SUMO Omni Beanbag
120 LED Assortment Package
If you’re busy, maybe you just don’t know how sweet some of this stuff is.
Fabienne kindly consented to give up her very own Hack-A-Day engraved iPod nano. It’s been used and the inside thoroughly inspected, but it’s otherwise unmodded.
MAKE gave us one of their new open source MAKE controllers – I opened up the one they sent and it’s pretty sweet. The 55Mhz Atmel SAM7X CPU is on a daughter-board, and the main board has terminals for every connection you could want, along with USB, Ethernet, CAN, Serial… They also sent along one of their new Daisy MP3 player kits. Unlike the controller, this one has to be put together.
Andrew over at sumolounge.com hooked us up with one of their SUMO Omni bean bags. This thing is awesome. It’s the biggest bean bag I’ve ever seen. (I may have to buy the winner another one, my daughter has been going nuts over it )
Finally, [Alan] of Alan’s Electronic Projects sent us a set of his 120 LED assortments along with a handy resistor pack for using them with 5vdc to get things going. The set even includes some 13000mcd white LEDs for making your own portable tanning device.
How do you win all this sweet stuff? You send in a design! You’ve got until December 25th!