Playing with a surplus E-ink module


Sjaak @ writes:

When I was in China last year I sourced a couple of small E-ink displays (GDEH0124S01) through Taobao. They were simple ones with 8 14 segment characters. After some searching on the Chinese website from the manufacturer I found the datasheet. It was by all means not complete and a lot info was missing. After a bit more searching I found the controller used is DM130120 and its datasheet tells a bit more…
I made a PCB quite some time ago, but due to personal matters, I hadn’t the time to solder them up and write some code for it. A couple of days ago I soldered the PCB and fired up the compiler. After struggling through both of the chinglish manuals I converted their pseudo code into something the compiler and the micro understands.

More details at blog.

Akiba: Shenzhen in 30 Minutes

Multi-talented hacker extraordinaire and electrical engineer [Akiba] is based in Japan, and this makes it just a hop, skip, and a jump over to Shenzhen, China, the hardware capital of the world. He’s led a number of manufacturing tours aimed at acquainting hackers with the resources there, and now he’s giving you the benefit of his experience in a 30-minute video. It’s great.


When [Akiba] is in Shenzhen, he picks up all the same commodity parts that you would, because they’re just so cheap. And Hua Qiang Bei is its epicenter: it’s a gigantic market for components, and they’re all being sold at rock-bottom prices.

cropped_shot_2016-12-07-131042But as [Akiba] mentions, just walking around the Hua Qiang Bei market also gives you a feeling for what’s currently in mass production, and this is useful for planning which parts you’d like to use for your own projects. Parts that are too old may go out of production soon, while the newest chips off the factory floor demand a premium. Walking around Hua Qiang Bei, you can get a feel for what’s in the sweet middle. [Akiba] also likes to do his product sourcing in Shenzhen. If he needs a USB cable to go along with one of his own designs, he’ll need a bunch of them cheap.

[Akiba] also mentions that Hua Qiang Bei is gentrifying. Rents for floor space are going up, and this naturally reflects in the prices. For non-consumer electronic or mechanical parts, he’ll often take an hour’s drive to the DoFu industrial electronics market. If you’re shopping for stepper motors or ball screws, that’s your destination.

Outside of the obvious hacker goods, you can get basically anything else made in or around Shenzhen. For instance, most of the world’s gems go through the jewellery markets of Guangzhou, and if you want to see buckets of rough blue topaz, head on over. You can also get custom jewellery made, so if you want to embed an RFID card in a ring and have it look professional, this is where you can get it done. Need rhinestone t-shirts with your hackerspace logo? Of course you do!


Custom USB Drives, Anyone?
Custom USB Drives, Anyone?

The market for customized products lies somewhere between doing a ground-up design and buying already finished goods. In his example, [Akiba] mentions a silicone rubber factory. If you need a custom design, the die and tooling alone can cost you $1,000. If you can use a pre-existing design, and tweak it minimally or add a logo, then you can avoid the tooling costs. For a run of 1,000 silicone widgets, at a per-unit cost of $1 each, using a customized version can save 50% of your bill. The same goes for cell-phone cases, game controllers, or USB keychains. Seeing samples and the possibilities of customization can help inspire you as a designer.


The prototyping resources available in Shenzhen are amazing: nobody bothers owning their own laser cutter because you can just walk down the street and get it done on someone else’s on the cheap. The same goes for 3D printing, fiberglass molding, and of course PCBs. If you’re sitting there with a PCB and parts in your hand, there’s no reason to pick up a soldering iron yourself either. There are assembly houses that will put together five fairly complicated boards for you for around $30 per board, with 24-hour turnaround!


cropped_shot_2016-12-07-131101The question [Akiba] gets all the time is how to get stuff manufactured in Shenzhen. And he cautions that a ground-up manufacturing run is the most complicated and risky option available, and maybe not for newbies. Visit the factories first, with a physical sample in hand. If they can see a final prototype, they know you’re serious and can even bring in an engineer to start talking manufacturability with you. And this is doubly important for plastic injection molding; you don’t need to know about the intricate details of the art, but you need to be able to talk with the engineer about what needs to change to make it work well and inexpensively.

If you’re going the manufacturing route, consider using a contract manufacturer (CM) intermediary rather than going to the factory directly. The CM will have relationships with multiple factories, and a reputation to uphold. They’ll make everything smoother.

Logistics and Fulfillment

cropped_shot_2016-12-07-131016You’ve built a product, gotten it manufactured, and now 10,000 of your new widgets are sitting on palettes in Shenzhen. What next? [Akiba] thinks that the logistics can be even more intimidating and complicated than manufacturing. Small quantities are easier, and above 20 kg cost about $5 per kilo. (Pro tip: if your package weighs 18 kg, it’s cheaper to put 3 kg of rocks into it than to leave it as-is.)

Bigger product runs get expensive, but [Akiba] breezes through air and sea freight. You’re in for a few thousand dollars here. Air is fast, but sea is cheaper and essentially unlimited in quantity. Get door-to-door service unless you want to drive down to the docks and unload the container yourself.

How do the small sellers on eBay ship internationally for free then? Well, it’s not free. $0.74 is about 5 RMB, which is the cost of a packet by China Post, and is not coincidentally about the minimum price of an item that you’ll ever see shipped “free”. Deals between China Post and the US government mean that it’s sometimes cheaper to ship from China to LA than from San Francisco. And this means that it might even be cheaper for you to do your fulfillment on a per-item basis directly from Shenzhen. Of course, this means hiring a fulfillment firm.

And Next?

[Akiba] has been giving design, prototyping, and manufacturing tours of Shenzhen for a few years now, and has seen several hacker products emerge. What’s he looking forward to? Getting more women involved in the process, and also helping charities and NGOs harness some of Shenzhen’s manufacturing might. If a book can be printed and bound for around $1, and shipped overseas for a few cents per copy, think of how cheaply you could outfit schools in developing countries.

Filed under: cons, Featured

Quickly Prototyping X-ray Backscatter Machines

Ben Krasnow is one of those people no one has a bad opinion of. He’s part of the team at Verily (Google’s Life Science Alphabit), where he’s busy curing cancer. He co-founded Valve’s hardware division and his YouTube channel, Applied Science, is an exploration of building very high-tech tools very quickly and on a very low budget. Ben has built everything from an electron microscope to a liquid nitrogen generator to a robot that makes individual chocolate chip cookies with ingredients in different proportions. He’s curing cancer and finding the perfect chocolate chip cookie recipe.

The focus of Ben’s talk at this year’s Hackaday SuperConference is building low-cost scientific apparatus quickly. From Applied Science, Ben has cemented his position as a wizard who can find anything either on eBay or at a surplus store. The real trick, Ben tells us, is getting his boss and accounting to understand this rapid prototyping mindset.

The first build Ben walked the SuperCon through was a device to test a hypothesis. Were X-ray backscatter machines, the devices found at airport security lines from about 2009 to 2013, actually effective at stopping terrorists? Although there are obvious safety and civil liberties questions raised by assessing X-ray backscatter devices, this is simply a question on the effectiveness of the TSA’s fanciest new gear. Do X-ray backscatter devices stop terrorists more effectively than a metal detector?

A chicken, wearing a sweater, and smuggling an allen key onto its flight. Chickens can fly.
A chicken, wearing a sweater, and smuggling an Allen key onto its flight. Chickens can fly.

The answer to this question came in a one-month build. Even at the beginning of the build, Ben says he didn’t know much about X-rays. Backscatter X-ray machines aren’t like what you would find at a dentist’s office – those are transmissive X-rays, and giving millions of flyers X-rays every day would be a worldwide health crisis.

Instead of shooting X-rays through everyone who goes through a TSA checkpoint, backscatter X-rays operate on an entirely different principle. After a quick patent search, Ben found a very good description of what backscatter X-ray scanners do, and began work on constructing a prototype to assess the effectiveness of these devices.

The build consisted of an X-ray source easily found on eBay, a phosphor screen found on eBay, a photomultiplier tube found on eBay, and a few bits and bobs kicking around the junk bin in the shop. Although you can simply buy a Rapiscan Backscatter machine (taken from an airport on eBay), that would cost several thousand dollars. Ben only spent a few hundred on his machine.

After building a device to scan an object with X-rays and detect the reflected photons, Ben had a working backscatter X-ray machine. It successfully detected an Allen key being smuggled by a chicken onto a plane. It’s a simple setup, but it proves you can make very complex devices very easily using parts bought on eBay.

The take away from Ben’s talk is simply rapid prototyping. Iterate often, find all the information that’s readily available online, and build prototypes quickly. Leverage the availability of everything being for sale somewhere. Build first, and ask questions later, and you might have the time to discover the perfect cookie recipe.

Filed under: cons, Featured

First GD32 tests


Sjaak has published a new build, the STM32/GD32F103 QFN32 breakout board:

Uptill now I used 0603 sized resistors and capacitors but for this project I switched to 0402 to save a few mm on the board. I have soldered many challenging chip packages so I felt confident. The technique is the same as for bigger sized devices: flux the area generous, hold the device with tweezers, solder one pad with fresh soldered iron and move the device into the molten solder puddle, retract the soldering iron and watch the solder joint cool down. If the solder joint is solid solder the other side too. I suggest using a fine (curved) tweezer and lots of lighting on your workarea. If you are a bit older as I am using a loupe or magnifying glass. Still use flux as much as possible. Never expected but the micro USB connector gave me (several) headaches to get it soldered properly.

Project info at


UCload: revisited


Sjaak has posted an update on his uC controlled dummy load project we covered previously:

I finally found some time to check out the UCload project. A couple of weeks ago I quickly soldered the PCB and wrote a quick’n’dirty firmware for it. The basic functionality was working, but it wouldn’t do good for the shiny display.
Today I locked myself in my mancave and shut myself off from the world. Turned the light down, pulled loud music from the speakers and started coding like hell!! Not exactly but I found some time to write some more decent firmware for this load. In a previous revision of the PCB I forget the pull up resistors and swapped the SDA and SCL signals. I corrected that and made some small other changes (still ****ed up the silkscreen) in revision 2. The hardware is quite OK and rock solid (prolly more due to the robust FET then my analogue skills :)). However I managed to use a 1n4148 diode to measure the temperature. Connect it to the heat sink and if that one gets to hot turn on a fan. It accuracy is terrible but capable of detecting over temperature :)

More details at project page.