Today's kind of hardware hack is one that I wouldn't have believed possible... Who would have thought that you could power a Kinect with some AA batteries and that it would be usable for hours?
As you know, we love our Kinect device, but one of the big problems when you want to play with it is that it’s a powered device which means you need to be close to power, or have a really long extension cord which isn’t always convenient. We decided we wanted to make a battery pack so we can take it and and our laptop and not be tied to needing a power point nearby. To build it we had a few criteria:
- Cost – something relatively cheap to buy/replenish
- Form factor – something that won’t draw too much attention/questions if we want to take it on a plane
- Easy build – something we (not electrician) can build relatively easy ourselves.
We settled on making a “AA” powered pack. This would draw no questions at airports and won’t be an issue taking on a plane and the added bonus is if it doesn’t work, the batteries can be used in many other devices. This meant for a normal AA we’d need 8 batteries to make 12 Volts! This could get expensive quickly depending on how quickly they go flat so we decided rechargable AA’s would be more practical in the long term. These however, are only 1.2 V so we needed 10 of them.
Next I wanted to be able to plug back into mains, or car etc if we needed rather than being tied permanently to the battery pack. So we went to JayCar and got a few bits and pieces that satisfied our needs. We ended up with:
Project Information URL: http://www.soulsolutions.com.au/Blog/tabid/73/EntryId/823/Making-a-battery-pack-for-your-Kinect.aspx
Now to the fun bit – testing the battery life. We hooked up the Kinect with it’s battery pack to our computer and ran the Kinect Explorer sample with full colour, depth and skeleton. Out initial calculations led us to believe we could run on batteries for 8 hours. Now our math for this type of thing doesn’t get used often so it was quite possible that we were out by a factor of 10….which could mean it might only last about 48 mins. So we took voltage readings and checked the Kinect and the Kinect Explorer were still running every 10 mins to make sure it could run for at least 45 mins.
After 2 hours we then dropped back to 20 min readings and then hourly readings. After 6 hours it was still going and although I’ve seen articles saying people have been able to run on a much lower voltage we didn’t want to test our luck. 6 hours is a LONG time. Also, the likelyhood we’d ever want 6 hours of video or readings on our trip is EXTREMELY low. The data would be huge and the battery in my Surface would have run out by then anyway.
When walking around with the Kinect on the dolly, the battery pack sits in your hand nicely with the Surface on top so you can see what you’re recording. We’re planning on giving a good test with PointStreamer and other Kinect features with some lion cubs in a few weeks. Hoping it’ll make for some interesting video and pictures as long as they don’t chew through our cables in the first minute.
Project Information URL: http://www.soulsolutions.com.au/Blog/tabid/73/EntryId/825/Battery-life-test-on-portable-Kinect.aspx