Here’s a cloud-connected outdoor temperature module on the 23rd storey at Yonge and Wellesley in Toronto. The ESP8266EX WiFi controller reads a DS18B20 digital temperature sensor every 30 seconds, continuously updating the data to ThingSpeak. This proof-of-concept prototype demonstrates the ability to collect remote data and upload it wirelessly to a web-based IoT message broker.
Here’s the board perched upon my balcony rail, hand-wired by yours truly:
It’s comprised of a first-generation module from AI Thinker that integrates the WiFi controller from Expressif Systems and a printed circuit antenna.
What’s cool about the ESP is that it incorporates an integrated 32-bit Tensilica MCU that can be programmed as a general purpose processor. This eliminates the need for a separate onboard Atmel or PIC microcontroller, opening the door to some super-small, low-power embedded designs with the WiFi stack built in. There are several SDKs currently available and the device can be programmed in C++ and LUA, with the NodeMCU firmware.
This board has been running for a week now on a single set of AA batteries — it’s completely standalone and wireless. It updates every 30 seconds from my balcony directly to the cloud. The chart below is updated moreless in real time as we speak…
My next-gen prototype is more refined and much smaller. It utilizes the latest ESP-12F module and has four sensors: temperature, humidity, barometric pressure and light level. It’s about two inches long, and I’m hoping to run it from a tiny battery from within a pill bottle. This should be online later this week.