Just a quick wrap-up before I disappear into the darkness of the month or so of mid-year break (which means I’ll actually have a chance to get some work done and hopefully come out the other side with an up and running prototype)…
First up, a new mockup design of the device(s). Sticking with the idea of trying to isolate each sensory focus (audio, visual and tactile), I’m dividing the box into respective quadrants (the fourth being the ‘brain’ of the device):
- Audio (image left) – RFID controlled Wave (audio) Shield
- Tactile (image top) – flex sensor controlled vibrating motors
- Visual (image right) – RFID controlled EL wire
Something that has changed recently is how each sensory element will be connected to the ‘brain’ of the device. I was quickly running out of input pins on the EtherTen microcontroller (image bottom) and some of the shields I am using are also using conflicting pin setups – most of which are not reassignable. To get around this problem as quickly and easily as possible (my strengths do not lie in electronics), I will daisy-chain an Arduino Uno from each of the interactive quadrants to the EtherTen.
It turns out that this is quite simple, using serial communication between each microcontroller. The information I am passing between each is very limited (is the device being used or not?), so the limited bandwidth of a serial bus isn’t a problem. It didn’t take long at all to get a couple of Arduino microcontrollers speaking to a EtherTen…
That pressing issue out of the way, I’m now starting on each sub-device. Without the hassle of pin conflicts, the Wave Shield is triggering its little heart out when launched by individual RFID tags (the card in the video is not programmed, therefore gives a negative reading and does not launch an audio file)…
By modularising the project as much as I can, I’m really hoping that I can get the first prototype into the home before the end of the break. There are a couple of big hurdles to come to terms with (particularly getting the right amount of current into the EL wire, via PoE looks to be a bit tricky), but it’s nice to finally see it taking shape, and it will be exciting to start getting real world feedback very soon.