With all the Kindles and Nooks we’re bound to find at yard sales and thrift shops in the coming years, this might be useful. [Chris] made a door-mounted e-paper display to keep himself up to date on recent events.
The hardware comes from an e-paper development kit [Chris] and his friend [Deian] were given a few years back. The dev kit sat in a dusty drawer until [Chris] decided to do something with it. With his door looking like a suitable palette, [Chris] decided to make an information panel that displays the date, his calendar, the weather, and a few RSS feeds.
There was already a Gumstix single board computer attached to the e-paper display, so [Chris] wrote a few scripts on his server and upload information to the paper display. The server renders the display as a PNG image at 800×600 resolution, converts it to PGM and compresses it for the Gumstix. There is a script running on the Gumstix to download the image from the server every five minutes and put it up on the display.
With the awesome readability and low power consumption of e-paper, we’re surprised we haven’t seen a project like this before. Guess we’ll have to wait until Kindles start showing up at flea markets.
While e-paper is common among e-readers, there are very few, if any phones other than the MOTOFONE that exclusively use an e-paper display. [Steve] had one of these phones sitting around and thought it could be used to build a low-power clock. Since the bistable e-paper display can retain the currently active content even when power is removed, he would only need to update the clock once a minute, when the time changed.
Unfortunately for him, very little publicly-available documentation exists for the display controller Motorola used. To get an idea of how the display was driven, he had to sniff the SPI communications between the processor and the display. Once he had the basic commands down, he spent quite a bit of time figuring out how to activate the different segments of the display, due to what seems to be a rushed design process on Motorola’s part.
Now that [Steve] had reverse-engineered just about everything, he connected the phone to a TI MSP430 to drive the display. He programmed the LaunchPad to serve as a basic clock with great results, as you can see in the video below.
If your interest in e-paper hacking has been piqued, be sure to check out our previous e-paper coverage here.
Continue reading “Reverse engineering a mobile phone e-paper display”
The people at iFixit have shown that they’re still on top of their game by tearing down the new Kindle 2 eBook reader. The main processor is a 532MHz ARM-11 from Freescale. Interestly, there isn’t any significant circuitry behind the large keyboard; it seems its existence is just to hide the battery.
Related: previous teardowns on Hack a Day
[Alanson Sample] and [Joshua R. Smith] have been experimenting with wireless power transfer for their sensing platform. Their microcontroller of choice is the MSP430, which we used on our e-paper clock. They chose it specifically for its ability to work with low voltages and they discus its specific behavior at different voltages. The first portion of their paper uses a UHF RFID reader to transmit to the sensor’s four stage charge pump. They added a supercap to provide enough power for 24 hours of logging while the node isn’t near a reader. For the second half of the paper, they use a UHF antenna designed for digital TV with the same circuit and pointed it at a television tower ~4.1km away. It had an open circuit voltage of 5.0V and 0.7V across an 8KOhm load, which works out to be 60uW of power. They connected this to the AAA battery terminals of the thermometer/hygrometer pictured above. It worked without issue. The thermometer’s draw on a lab power supply was 25uA at 1.5V.
It’s an interesting approach to powering devices. Do you have an application that needs something like this? For more on wireless power, checkout this earlier post on scratch building RFID tags.
If you’ve never heard about electronic paper, crawl out from under that rock and read up on the Sony Reader and the Amazon Kindle. E-paper is a flexible display made of color-changing beads that mimic ink-on-paper for easy daylight reading. The revolutionary thing about e-paper is that after it’s set, it stays that way without additional power.
This sounds great in theory, but Esquire’s cover is the first time everybody can afford to hack an e-paper display. We took the cover into the Hack a Day lab to document, test, and hack. In the end, we recycled it into something useful that anyone can build. We’ve got all the details on how the display works and what it takes to use it in your own projects. Read about our e-paper clock hack below. Continue reading “How-to: Make an e-paper clock from Esquire magazine”