Dance the rainbow

By Les Pounder. Posted

Think wearable technology and we instantly think of jewellery, sewable LEDs, and light up hoodies. But a few years ago we saw illuminated shoes enter the world, most notably from our very own Dr Lucy Rogers, who wore them to an evening with HRH The Duke of York at an event to celebrate the Raspberry Pi community. Lucy certainly made an entrance and lit up the room with style.

So how easy are they to hack, and can we use them in a project? Well there's only one way to find out. Let’s take one apart!

General Construction

Made of synthetic ‘leather’, the uppers are pliable and easy to work with using conventional hand tools and knives. The soles of the shoes are a rubberised plastic which is used to diffuse the LEDs and provide an adequate level of grip. Moving inside the shoe, and the synthetic leather is protected from sweat via a semi-breathable fabric that has an almost ‘rubbery plastic’ feel. Between the outer and inner layer is a foam layer that offers comfort to the wearer and rigidity for the shape of the shoe. Still inside the shoe, and the sole is a two-part construction, with a replaceable sweat barrier on top of a non-replaceable membrane used to keep the electronics in place.

Inside the sole are the electronics and the LEDs, as well as plenty of space! The soles are hollow with a series of inner support structures used to contain the electronics and prevent the weight of the wearer from crushing everything. The internal support structure is easy to work with using hand tools; rotary ‘Dremel’ tools would also make short work of the plastic used, but remember that you will need to add support to stop the wearer crushing the electronics – oh, and for comfort!

Sole

Talking of crushing, the electronics are ‘potted’ in a block of resin. This means that they are not easily accessible, if at all. The resin is tough and it surrounds the battery and electronics. The best way to get access is to use side cutters, not your best ones, and snip away at the plastic container to reveal the resin. The next bit requires a little ‘brute force and ignorance’ to get into the resin. A rotary tool will make the task much easier, but be very careful, as LiPo batteries do not like being punctured and can cause fires, so only try this if you know what you are doing!

Power

Each shoe has a non-replaceable LiPo battery, rated at 3.7 V 450 mAh, which is connected directly to the electronics that control the LEDs. Charging the battery is handled by a micro USB interface that is sewn into the layers inside the shoe. Both shoes can be charged at once using the included USB ‘A’ to micro USB connector.

Electronics

Electronics

The circuit board is identical for each shoe, and it features an unknown eight-pin chip that is used to control the LiPo battery charging and boost the 3.7 V voltage from the LiPo to the 5 V used by the LEDs. The LEDs themselves are not WS2811 / WS2812 ‘NeoPixels’-intelligent LEDs, instead they are 5 V RGB, which can display red, green, and blue, or a mix of each colour. The colour is controlled from the circuit board by use of a common 5 V power, requiring the choice of colour by pulling any of the RGB pins to Ground.

While this may be ‘primitive’ compared to NeoPixels, it does mean that we can control the LEDs using any single board computer or microcontroller, for example Adafruit’s Trinket M0, or Feather range of boards. But this would also mean sourcing a replacement LiPo battery and charge circuitry, which can easily be found in dollar store / pound shop LiPo batteries. There is plenty of space inside the sole of the shoe in which we can add our electronics; keep in mind that any electronics inserted into the shoes will need to be enclosed in a barrier to prevent moisture, and stop the weight of the wearer from crushing the kit.

Conclusion

These shoes were made for hacking, and that’s just what we’ll do. These shoes are your route into cheap wearable hacks. They do not need to torn apart to get access to the electronics, so a sympathetic hack is possible. For those more daring, the liners inside the shoe can be torn away to reveal the internal support structure and with that we can place our own electronics. Two great hacks for these shoes would be to use a controller with Bluetooth support, and then use an application on our phone to control the LEDs in our shoes! Also using a sensor to detect a footstep, and then causing the lights to pulse, would make for an effective and useful hack for joggers.

Replacing the LEDs with NeoPixels is also possible, for those who are daring! But replacing the LEDs with NeoPixels would offer much more flexibility and control. Imagine a scrolling ‘marquee’ or rainbow effect as you walked.

No matter how you hack these shoes, you will make an entrance at any party! Be bold, stay safe, and keep on hacking!


http://bigl.es

From HackSpace magazine store

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