Malaria kills each year more than 400 000 people. Insecticide-treated nets had been really effective in decreasing the number of contamination, but mosquitos are developping a resistance against these chemicals.
Squitosplit is a mosquito net which detects if a mosquito has land on, and then shocks. The detection works with a capacitive technology.
The net is able to distinguish a human from a mosquito, avoiding shocking a human.
We are working with universities, NGO and companies to respond to local needs and to have feedbacks from experts.
We are unified in a non-profit. This project is openhardware/opensource.
Jeanne Lallemand, who studies industrial design at ENSCI Les Ateliers and manage the communication team of Tica, has just published our new website! Jeanne has done lots of drawings to make it nice to look at.
To measure the capacitance of a capacitor, we have decided to make a RC circuit (resistor – capacitor): first, we charge the capacitor, then, it discharges itself in the resistor.
We take (you can change the values, it depends in fact of the range that you want, mine is for capacitors around 1µF)
R = 1k = 103 ohm
t = 10-3 s
V0 = Vcc = 3.3V, corresponding at 4095 when read with AnalogRead() on Esp32, or 1023 on Arduino uno
I have left the loop running 24 791 times, and calculate the average and the standard deviation with Excel.
We find 935,7 nF, with a standard deviation of 2.99, which is quite good!
Using my multimeter, I find 962.5nF. The difference is probably due to the internal resistance and capacitance of the ESP32 board.
We have used an esp32 devboard as microcontroller, but you can use an Arduino board. The code would be the same.
Be careful: Arduino uno has a 10-bit ADC (analogic digital converter), ESP32 a 12-bit ADC: so the values returned by Arduino would be comprised between 0 and 1023 (210 values) and ESP32 between 0 and 4095 (212 values).
Use in our mosquito net :
Our net is a sort of capacitor, the human body is a capacitor too. In fact, any material behaves as a capacitor. When a human approaches, the capacitance of the global system is modified. We can detect this variation in order to stop applying electric shocks.
We don’t need to really calculate the capacity, we will only analyze the voltage of the capacitor (using the same circuit), because the voltage after a time t is related to the capacitance.
Avoiding complicated calculations permits to limit the use of energy and time resources.