The Air Quality sensor that I’m working on uses a GPS receiver and particle sensor. Both these devices use a serial connection to deliver their values into the processor. This poses a problem, in that the esp8266 (the chip that I’m using) doesn’t have very many serial connections. The usual solution is to use a software simulation of a serial port instead of a “proper” hardware one. The difficulty with this approach is that software serial ports slow down the processor because the processor has to stop and wait for each incoming character.
To solve this problem I’ve written an interrupt driven serial port that uses the edges of the serial data stream to trigger readings, which means that it doesn’t hold things up as much. You can find out more in the video above. You can download the code and play with it here.