What happened related to our project in the last 3 days? One major change and many questions.
First, I spent some time looking for an appropriate battery for our plant. I found a power bank that met our requirements (in fact, we would have needed 2 of them). But they were pretty big. So I proposed to turn the plant from energy autonomous to a plugged product. Our banana tree is not so small so users won’t move it every day, consequently it’s not a problem if it’s plugged. And we decided to choose this alternative.
Then, I looked for an appropriate power supply. This forced us to choose which LEDs we want to use. And for now, we’re still not sure: the most powerful ones consume a lot so we can have only a limited number of them, but the others heat a lot, which can be a problem. We tried to imitate diffusing optical fiber and tested it with both LEDs to help us in our choice, but it didn’t work well with both LEDs. We hope that it will work better with true diffusing optical fiber. Now, we’re waiting for Alexis and Samuel opinion on the LEDs choice
Beside this, I chose a power supply bloc (5V 12A DC out) and found regulators (one for supplying energy to the ICs and another to provide energy to the Flexinol). The LEDs will be plugged directly on the input power line.
I also tested the capacitive proximity sensor with the banana tree: after some tuning, it worked well !! This solution is thus definitely validated.
And finally, I tried to allocate the micro-processor pins (we’ve chosen a STM32F405) to see if 64 pins are enough: we can’t put as many LEDs and Flexinol as we wanted first, but as their number will be limitated by the power supply, maybe 64 pins will be enough.
For the end of this week, we have to finish the electrical schematic. I will take care of the processor part (pins allocation) and of the power supply part. I also want to improve my touch/proximity detection algorithm and if it works well, why not try to detect more complex patterns like sliding.