Plotsensor's cuplTag Sends Environmental Sensor Readings via NFC — By Encoding Them in a Lengthy URL
Fully open source, this seven-year-plus battery-powered environmental sensor has a neat way to get its readings into your hands.
Oxfordshire-based Plotsensor has launched its inaugural cupl-brand product, the cuplTag, for crowdfunding — a compact environmental sensor that lets you take a reading by simply tapping it with any NFC-enabled phone.
"cuplTag is a battery-powered NFC tag that logs ambient temperature and humidity," the company explains of its creation. "Tap it with an NFC-enabled phone and you will see timestamped readings appear in a web application. It’s a one-step operation that requires no configuration and no app installation!"
The open-hardware gadget is designed, Plotsensor says, for hackability — which does, sadly, mean it's not water resistant and thus only suited for indoor use. Its use of NFC means there's no software to install, though the tapping device needs an active internet connection, and battery life is strong — seven years plus, the company claims, "depending on the operating environment."
The on-board sensor logs temperature and humidity every ten minutes, a default setting which can be change from a minimum of three minutes to 65,535 minutes, storing readings in a 1kB circular buffer which can store 188 combined readings or 376 temperature-only readings. The reason for the relatively low total: The readings are stored in a long-format URL. When the tag is tapped, the URL is sent to the phone and opened in the browser — transmitting the results to Plotsensor's platform for storage and graphing.
The project is fully open source, from the firmware that runs on a Texas Instruments MSP430 microcontroller to the designs of the PCB. All files have been uploaded to the cupl GitHub repository ahead of the completion of crowdfunding, which is to run for the next 34 days at the time of writing.
The project is raising funds through Crowd Supply, with physical rewards starting at $39 — though anyone wanting to reprogram the gadget will need an MSP-FET flash emulator, which is available for an additional $153. Hardware is expected to ship at the end of January 2022.