txtr Beagle teardown and reverse engineering - Page 1
Forum section: electronics / general

author: brainwash
author_rank: Frequent Contributor
timestamp: July 17, 2013, 11:12:42 pm
content: I just got mine today so it was off with the covers:http://hackcorellation.blogspot.de/2013/07/txtr-beagle-teardown-part-1.htmlSomething related to the display seems to have broken while taking it apart (damn glue) but this thing costs less than a pair of quality screwdrivers.I'm uploading some videos to youtube, hopefully the web editor does non-linear stuff because I was using two cameras.Next stop will be the Android app, hopefully it's standard Java and not NDK. Though usually only apps ported from i-devices are using native code.Regarding the blog, I've just started using it now, I'm starting work in one month and have to centralize quickly all the stuff I did somewhere. I'm open to any suggestions like font size, scheme colors or whatever.

author: mariush
author_rank: Super Contributor
timestamp: July 18, 2013, 01:02:51 am
content: Looks interesting.If I were to guess, I would say they probably use some sort of RLE compression on each page. The screen is 800x600 with 8 gray variations, so that would mean 3 bits per pixel.But I personally wouldn't complicate my life and increase cpu usage messing 3 bits at a time, so I'd probably use 4 bits per pixel and use that extra bit as a sort of flag (if set, the next 3-7 bits hve a particular meaning)Even at 4bits per pixel, it's 235 KB/page.. 400 MB used for 5 books i kind of a lot, i doubt those books added up totaled 1700 pages or so.If you want to decode the format, I'd suggest making up a pdf with a . on a single page, two dots on a single page, a | character, a hyphen - the converter may do some damage but you should still get some idea about the pattern used.

author: brainwash
author_rank: Frequent Contributor
timestamp: July 18, 2013, 01:09:02 am
content: I don't know how to attach the file since it's quite big. Also I did not search how to do a hex listing so here's just a screenshot, first one from the start of the file, the second one at around 5% mark.

author: brainwash
author_rank: Frequent Contributor
timestamp: July 18, 2013, 01:13:26 am
content: Quote from: mariush on July 18, 2013, 01:02:51 amThat's against the product idea!You can only upload books from their store/app which is the reason why I started this endeavor in the first place. It's cheap, light and economical enough to be used as a display.Unfortunately, I don't think bluetooth can be activated by other means than that hardware button and it deactivates itself automatically, so a remote display might require a few extra components.

author: amyk
author_rank: Super Contributor
timestamp: July 18, 2013, 11:23:35 am
content: Have you tried dumping the firmware?It somewhat reminds me of the digital picture frames, which are similarly simple, although those use an 8-bit CPU (usually 6502).Photoshop can open a "raw" image file and even if you don't get the parameters exactly correct it's often enough to see some image-ness and figure out the rest.

author: brainwash
author_rank: Frequent Contributor
timestamp: July 18, 2013, 11:58:05 am
content: I've had an hour to play with the app and figured it just serializes an android bitmap object, after converting it to gfrayscale. The app has two renderers, one for epub and one for PDF. The decompiled sources are very readable, it's almost as good as open source. I expect a simple app can be written which can upload custom content to the reader

author: brainwash
author_rank: Frequent Contributor
timestamp: July 18, 2013, 02:16:15 pm
content: Part two:http://hackcorellation.blogspot.de/2013/07/txtr-beagle-part-two-software.htmlMost of the time is taken by the write-up than the actual 'hack'.

author: chicken
author_rank: Frequent Contributor
timestamp: July 18, 2013, 05:54:38 pm
content: Definitely an interesting way to get a cheap eink display, though I fear supplies and company won't last very long.Anyone knows where to buy one of these from the US? None on Ebay yet.

author: brainwash
author_rank: Frequent Contributor
timestamp: July 18, 2013, 07:02:28 pm
content: They will be available in the US very soon, AFAIK. I think they announced August as launch date. Just keep an eye onhttp://us.txtr.com/Crap, the txtr has sold out in Germany so I have no way of testing the image display, the COG might be busted on mine.BTW, the sd card has a page size of 40000h (65536*4) bytes out of which only 240000 seem to be used. Which is actually (800/2)x(600/2)x2, each pixel being a nibble, everything stored uncompressed. That's the easy part, the hard part is figuring what's the protocol for sending images, what I could figure out so far is a dithering+downconversion to 4bpp folowed by "deflate".

author: amyk
author_rank: Super Contributor
timestamp: July 19, 2013, 10:43:33 am
content: Quote from: brainwash on July 18, 2013, 07:02:28 pmThe CPU is a bit overpowered if all it's doing is reading images from the SD card and sending them to the display...

author: brainwash
author_rank: Frequent Contributor
timestamp: July 19, 2013, 11:29:55 am
content: I think the cost might be similar to an 8-bit micro with all the needed peripherals and considering the page sizes on the SDCARD a 32-bit micro is more suited to the task. I'm not saying it cannot be done, it just doesn't make any sense. Granted, I believe it's possible to have everything done on the ASIC.The most intensive task of the uC is to decode the incoming data stream, it's gzipped ("deflate" actually). Without that, each book page would have 234kbytes so a 300-page book would weigh in at 70 MB. Even as it stands, for transferring such a book about 2 minutes are needed, with compression on.Another business model that they can do is inject ads into the pages since they have full control over what's rendered, but they would have no way of tracking them.http://hackcorellation.blogspot.com/2013/07/txtr-beagle-part-3-storage-and-transfer.html

author: brainwash
author_rank: Frequent Contributor
timestamp: August 02, 2013, 02:18:47 am
content: Well, it seems there was only a fire sale (60% off) not the actual retail price. It was a time just before people went on vacation that capable but failed readers were sold at 29E, so the dumb reader had to be priced accordingly in order to get a bite of the market share.My addition to the teardown:"Edit 02 Aug 2013: I was not aware that eInk displays have not gone down significantly in price. I still stand by my initial 10-15$ estimation (not including NRE costs like tooling) but the electrophoretic displays still cost more than 20$.So it looks like the initial units were sold at a loss which is in line with the announced 60% price reduction. I very much doubt they will sell for 20E again unless they are dumping the stock or have found a magical way to make money off of them."

author: FrankBuss
author_rank: Unknown
timestamp: February 04, 2014, 07:09:57 pm
content: The txtr Beagle looks interesting, but I can't find it in their shop. There is the pagehttp://de.txtr.com/beagle/and then there is a the help page, which links to the shop, but no Beagle.BTW: a tiny 1.44" e-paper can be bought for EUR 8.21 for your own projects. I just tested the bigger 2.7" version:https://www.eevblog.com/forum/projects/e-paper-testI guess the price will drop a lot, if you buy higher quantities. But you don't get a full microcontroller system with SD card and bluetooth for this price, maybe they really sell the Beagle with a loss to promote their shop.

author: brainwash
author_rank: Frequent Contributor
timestamp: February 07, 2014, 08:56:43 pm
content: Some source said not too long ago that the business did not turn out as expected. The facebook page hasn't been updated since the July'13 sale.To be fair, the Kindle has been heavily marketed and discounted, while benefitting from a much larger production. I think it currently retails for around 49$/EUR, but when the Beagle was conceived it was selling for around 100$/EUR.Still, I think it was a nice design idea and with open software would have probably sold 'well enough'. I wish it would return to the market (for the same price) but my impression is that there was only a test production run of a few thousand devices.They are still available every two months or so on ebay, I wish I could buy a working one for more hacking. If anyone is willing to sell theirs just give me a shout.