Week 7
General ·This week Jussi finishes the new design of the flower pot. We have now on the bottom a water reservoir with an aperture to fill the water in a easy way without opening the assembly. Inside the arm we hide the peristaltic pump and there is also room for an Arduino Uno, even though we plan to not use it because we have our sensor board with everything we need to control the pump and sensor. the design of water dispenser is now more sleek and semi-circular, to give more room to the plant to grow.
For the sensor, even though the milling process was not 100% successful, Tapio fix it by hand so it can be used. We were not able to do the holes in the PCB so we find a “floating Arduino” solution to solder it just for testing.
Tiberio starts writing the software for it. We had two versions: one uses an open source library that sets an interrupt function when the analog comparator sees a CHANGE or FALLING or RISING edge, the other one does the same things bau we set manually the register of the ATMEL. Both version were not working. We connected the sensor and Arduino to oscilloscope to test, and even though the signal from sensor was crossing the reference one we were not able to get the interrupt. After several different changes in software (all failures) we discover that we have been using the wrong pins for analog comparator. Actually AIN0 and AIN1 pins used for analog comparator aren’t the A0 and A1 analog input pin, bu we have to use D6 and D7. After connecting the sensor correctly, it works!
In the following video we can see the reference square signal and the signal from sensor with the delay due to the capacitance and resistance. We set a demo version of software that turns on the LED when we enter into the interrupt. When we touch the sensor we can see the signal from sensor become slower due to the increased capacitance.
We also start to print the final models but we have some issues with LeapFrog Creatr 3D printer and our bottom plate got stuck during printing:
