GoNotify, a Flexible IoT Sensor Interface
Some time ago I wondered what the requirements for a connected device would be. First off, it had to be wireless, meaning it’s battery- or solar-powered. This in turn implies that it should consume as little energy as possible; hence it must be a low-power design all over. Furthermore, the system should be simple and low cost, and there should be no connection costs. Finally, the device has to be flexible and easy to develop with. Wi-Fi fits almost perfectly what I was looking for and the popular Wi-Fi chip ESP8266 makes this technology accessible at low cost. The low-power side of things, on the other hand, might be a challenge. With all this in mind I set out to work.
The design that I came up with consists of four major blocks (Figure 1):
• for Internet connectivity a cheap ESP-01S module containing the ESP8266 Wi-Fi microcontroller;
• an ATmega328PB to handle the sensors;
• a USB serial port for programming and debugging;
• a power module consisting of an LDO and a step-up regulator.