Batteries and wearable technology – frustrations & futures (maybe)

As anyone who has read a couple of my posts will know, I really enjoy creating wearable electronics and art, plus it’s such an exciting time to be working in this area as everything is still to play for in terms of what the future killer apps for wearable technology will be. I’m finding though, that my scope for what I am building and wanting to build is not so much limited by knowledge, imagination and bloody-mindedness to get code and hardware to work together, but increasingly how I can power my portable works without weighing myself down with a plethora of large & lumpy battery packs!

Most of the components and rapid prototyping kit (eg microcontrollers) that I use are not power hungry at around 5< Volts apiece and it’s easy to buy small holders for AA, AAA and coin cell batteries that aren’t too obtrusive if you don’t mind having a pocket sewn into your clothing somewhere strategic and a bit of lumpiness, plus some wiring to hide. But if you want to run more than one component, you get into problems of how to power them simultaneously and it’s usually a no-no if you want to use one small battery pack – then it ends up with me getting my oscilloscope out to try to work out what’s going on.

Hacking the Heart Spark with a proximity sensor - testing on the sillyscope

For time based events, such as a fun night out at White Mischief, wearing electroluminescent accoutrements such as el-wire and panels is fine, but I have to carry a bag of batteries around with me for my 4 x AAA powered inverters that require changing every two hours. It’s not always easy to negotiate a huge tutu and corsetry in toilet cubicles for changing batteries – but I guess you could try to argue that’s my error for choosing such impractical garments, though for a performer a quick battery change is probably a bit more crucial. On the other end of the scale I make electronics for more minimalist garments such as t-shirts and necklaces, which can induce a conundrum to find somewhere to hide the batteries!

Hactivate: battery pouch made

I’ve considered using Li-Po batteries, which are in common use in mobile phones and the laptop I’m typing on right now, and people do use them for wearables. Personally, I’m not convinced I’d want them close to my skin as they can get hot or in garments that stand a chance of getting wet or punctured as Li-Pos can be rather volatile (& I have considered making polymorph cases for them). They’re not fundamentally unsafe, they’re just a little more cumbersome to charge than my regular household rechargeable batteries as they require a bit of attention to monitor charging correctly. I have them for use with microcontrollers already and I have a fire retardant charging bag for them as most guides recommend this, plus that you don’t leave them unattended while they’re charging. I’d be a bit hesitant to sell someone a garment that had Li-Po batteries if they hadn’t used them before.

LiPo-safe bag

My wearable technology work isn’t confined to arty el-wire outfits, I’m very interested in sensing wearables and have a stack of sensors that I use singularly or combined for tracking and sensing purposes., plus I have loads of other interactive components and conductive materials for pieces of work that have various current draws that I’d like to have some longevity and reliability.

Twinkle Tartiflette on new mannequin

In the wider world there are multiple areas and uses for wearable technology to consider that urgently need better battery capabilities. Firstly, medical wearables would really benefit from extended battery life, for example, my dear uncle has a pacemaker, which has a battery that needs to be replaced every 5-ish years, so for him battery life means another invasive procedure, with the stress and risks of infection, etc, which he could happily do without. Other, non-invasive wearable medical devices might give a good deal of relief and freedom to users if the batteries didn’t require a swinging handbag full of battery to cart them about. Sounds a small price to pay for freedom, but it would probably make life a bit easier if they weren’t so heavy, increase uptake of usage – plus take some of the stress out of choosing whether to use / invest in wearable / portable medical aids.

There’s also dangerous / extreme environments uses of wearable tech, where users may be out in the field or location for weeks at a time in extreme conditions, so you don’t really want your batteries to fail you or be a house brick round your neck when you’re already packing a lot of kit. You really need them light, very long lasting and capable of smart power allocation to make the best of each charge. It seems the military have the serious funding for tech advancements for wearables and I see a lot of awards for work in this area. Though how long it will take for the fruits from this research to be revealed and trickle down into for civilian use is anyone’s guess, but any battery enhancing revelations would be so useful for medical wearables, as well as lifestyle usage.

With the 2012 Olympics less than a year away, we shouldn’t overlook sports wearables either – as broadcasters wish to bring the sportsperson’s experience into our homes as well as athletes wishing for ever more robust measures of their performance – it’s not going to help if they’re running with a brick on their backs!

Battery life for portable electronics is a daily bugbear for a lot of people, most commonly smart phone users – many having to carry their chargers around with them or include remembering to plug in and charge every night in their bedtime routines. Addicted as I am to checking my email & Twitter (yeah, I know) I’d love to have my phone connected to the interwibbles all the time (yes, connectivity is often crap too), so I can just get an alert if I’m waiting for an email, reply or DM – I can’t have my mobile connected to 3G / wifi all the time the though as it’ll run my battery down really quickly. This makes for a very ‘opaque’ technology – I have to keep stopping what I’m doing and switching it on and off again, rather than a transparent technology that allows me to get on with my with what I’m doing as it checks things for me in the background. A classic example of this is me rushing off somewhere and nearly coming a cropper or being late because I’m faffing about with multiple phone screens as I connect and check my mail on my phone – oh yes and not forgetting the embarrassment of appearing rude in the middle of a conversation with a human IRL as I blatantly fumble with my phone for a couple of minutes!

I really believe that battery issues are majorly holding back integration and uptake of wearable technology into the mainstream – we have the capability to make very small components and wonderful inventions, but not so the batteries to power them for useful lengths of time or that do not require a trailing powerpack or brick of a battery in my undergarments!

'Yr in mah face' temp-sensing t-shirt

Ho hum, whilst I’m waiting for useful battery technology advancements, I’ve been looking into energy harvesting & scavenging technologies. Piezoelectrics and electrostatics are a good bet for biomechanical charging as if we can use our bodies and movement such as walking, dancing or just waving an arm to charge small pieces of wearable technology I’ll be very jolly. Plus there’s thermoelectrics that convert temperature differences from say the heat of your dancing feet to the temperature of the floor into an electric voltage (aka the Seebeck effect).

The above technologies would also be fantastic for remote areas and extreme environments where access to the grid or generators is minimal, plus would get a star for cutting down on pollution and energy costs. Unfortunately, I haven’t got very far in finding kits or components available to DIY this tech myself and am looking forward to access to this tech cascading down to peeps like myself soon. I’ve also got a small solar panel that charges a battery for emergency use, this is dependent on having access to sunlight, but unfortunately for me my particular off the shelf solar battery is just frustratingly crap even if I leave it in the summer sun all day, but that’s just bad gadget luck / design, rather than the overarching technology. Doing much better are thin sliver solar cells that are very thin and so are quite flexible and can be worn on garments and are complementary to extreme climates, they seem to have the military interested at least!

Anyway, to sum up, in my humble opinion it’s the military who currently seem most determined to find a solution for developing better battery life for wearables and portable computing, they have the drive and the funding. From my own research, piezoelectrics, electrostatics and thermoelectrics – energy scavenging / harvesting technology is the most fun, green and compelling solution for recharging batteries for low power wearables at the moment, especially in footwear and garments where components can find some space to be hidden away. There’s tons of stuff going on in nanotech improved batteries, better / smaller lithium-ion tech as well as different yarns, fibres, textiles and substrates such as graphene for deployment. Also changes in charging / battery management technology will get better perhaps, so that charging a battery only takes a few seconds rather than hours and will also release a charge more effectively.

Finally, I feel the demand for constant connectivity from consumers will get more urgent as battery drain in mobiles becomes more infuriating to users and drives technology brands to come up with solutions. There are currently teams working in research labs all over the world trying to crack this nut, so I am hoping the results will be fantastic and don’t take too long to get to us – the future, development and uptake of wearable technology depends on it!

Hactivate: You make my <3 flutter