Hackaday Prize Entry: Piezo Gait Analysis

Go into a fancy drug store, and you might just find one of the most amazing sales demonstrations you’ll ever see. Step right up, take your shoes off, and place your feet onto the magical Dr. Scholl’s machine, and you’ll get a customized readout of how your feet touch the ground. As an added bonus, you’ll also get a recommendation for a shoe insert that will make your feet feel better and your shoes fit better.

There is, of course, one problem with this setup. You don’t stand on a footprint measuring device all day. A better solution to the problem of measuring how your feet hit the ground is doing it while you walk. That’s where [chiprobot]’s Alli-Gait-Or Analysis comes in. It’s that Dr. Scholl’s machine tucked into the sole of a shoe. It can be worn while you walk, and it can tell you exactly how your feet work.

[chiprobot]’s robotic shoes consist of a 3D printed insert that holds eighteen piezo transducers per shoe. These are connected to ADCs, which feed into a microcontroller which sends the data out to a computer. That’s simple enough, but making sense of the data is the real problem.

To turn this data into something that could be used for selecting orthotics or simply finding a better shoe, [chiprobot] is plugging this data into Blender and creating some very cool visualizations. It’s good enough to get some serious data off a shoe, and since this Alli-Gait-Or is wearable, the data is much more valid than a machine sitting in a drug store.

Quad Serial Adapter

Despite concerted efforts to kill them, serial ports are alive and well, especially in embedded system. True, most of them end in a USB port, these days, but there’s still a lot of gear with a DE-9 (it isn’t a DB-9, despite the common use of the word) or a TTL-serial port lurking around. [James Fowkes] got tired of managing a bunch of USB to serial adapters, so he decided to build his own FT4232 breakout board that would provide four serial ports from a USB connection.

The small board has transmit and receive LEDs for each port along with EMI and ESD protection on the USB port. The ports are all TTL serial, serving the modern hacker, and the 3.3V pins are 5V tolerant.

Continue reading “Quad Serial Adapter”

Super In-Depth $15 Curve Tracer Project

[Jason Jones] has always wanted a curve tracer for his home shop. When he was starting out in electronics he fell in love with a machine called a Huntron Tracker 2000. This machine would feed a sine wave into a circuit on one side and plot a XY graph on the other.

[Jason] figured that with a modern microcontroller such a device could be build simply and cheaply for around $15 dollars. With that requirement in mind he set out to build it. He selected a PIC24F16KM202 for the brain and got to work.

The write-up is really great. It’s rare that someone puts every step of their development and design thinking into writing. Some have argued that this is the only true way to have an OSHW hardware project. The series covers everything from the initial requirements and parts selection to the software development and eventual testing of the device.

[Jason] managed to build a pretty capable little curve tracer in the end. We really enjoyed it when he used the tracer to debug the tracer.

One Man Spends 53 Years And Builds A Cathedral

Is it a hack? We think it’s definitely a hack. It’s just a hack that’s so grand and audacious it’s hard to even think of it as a hack. [Don Justo Martinez] single-handedly (aside from the help of an occasional nephew, which doesn’t count) built a Cathedral over 53 years in Madrid Spain.

Born in 1925, [Don Justo] found himself dying of tuberculosis soon after leaving a life of farming and becoming a Benedictine monk. He became so ill he was forced to leave his order and prayed for healing. He promised that he would erect a church in the name of the Lady of the Pillar if he lived.

He lived, and he built. He built out of whatever he could find. The broken bricks from the local factory became his cut stone. Discarded glass and metal all went into the work. The column forms are old oil drums. As Linus Torvalds said of the Linux project, (paraphrase) “Start to build it and they will come.” Once people saw the madman work, they began to donate materials to the Cathedral.

An untold number of very difficult man hours has gone into the structure. It makes the complaining  in the comments about the 100 hours spent on St. Optimus of Prime look as petty as it was.  It makes most arguments about time spent look silly. It’s labor and dedication on a scale that just isn’t often seen in any age.

In the tradition of cathedrals, [Don Justo] is likely to pass away before his church is finished. His only request is that he be the first to be placed in its crypts. His great hope is that others will continue the work after him. If you’d like to know more and see some pictures there is a website with more information.

Fail of the Week: Ferrofluid

It’s more of a half-fail than a full fail, but [Basti] is accustomed to getting things right (eventually) so it sticks in his craw that he wasn’t able to fully realize his ferrofluid dreams (German, translated here). Anyway, fail or demi-fail, the project is certainly a lesson in the reality of ferrofluid.


We’ve all seen amazing things done with ferrofluid and magnets. How hard can it be to make an interactive ferrofluid wedding present for his sister? Where ferrofluid spikes climb up a beautifully cut steel heart in a jar? (Answer: very hard.)

Continue reading “Fail of the Week: Ferrofluid”

It’s Not a Bridge, and Not a Tunnel. Or, Maybe it’s Both?

The gist of the idea is to suspend an underwater tunnel from floating pontoons. By the time you finished reading that sentence, you probably already had a list of things in your head that seem to make this a terrible idea. After all, it does seem to combine the worst aspects of both underwater tunnels and bridges. But, the idea may actually be a good one, and it’s already being seriously considered in Norway.

Continue reading “It’s Not a Bridge, and Not a Tunnel. Or, Maybe it’s Both?”

Tools of the Trade – Through Hole Assembly

In our last installment of Tools of the Trade, we had just finished doing the inspection of the surface mount part of the PCB. Next in the process is the through hole components. Depending on the PCB, the order may change slightly, but generally it makes more sense to get all the SMT work done before moving to the through hole work.

Through hole used to be the standard, but as the need for size reduction and automation increased, SMT gained favor. However, there are still a lot of reasons to use through hole components, so they aren’t going away entirely (at least not any time soon). One of the biggest advantages of THT is mechanical strength, which makes it better suited for connectors than SMT. If you’ve ever popped a microusb connector off a PCB by breathing on it heavily, you’ll understand. So, how do we most efficiently get through hole components on a PCB, and how do the big boys do it?

Continue reading “Tools of the Trade – Through Hole Assembly”