Temperature and humidity sensors would normally connect to a gateway sending data to the cloud, the coin-cell battery-powered cuplTag NFC tag instead sends data to your smartphone after a tap.
CulpTag is controlled by an MSP430 16-bit microcontroller from Texas Instruments which reads and stores sensor data regularly into an EEPROM, and the data can then be read over NFC with the tag returning an URL with the data from the sensor and battery, then display everything on the phone’s web browser (no app needed).
- MCU – Texas Instruments MSP430FR2155 16-bit microcontroller @ 24 MHz
- Storage – 2K bytes EEPROM part of NT3H2111 for up to 188 temperature & humidity data points or 376 temperature-only data points
- Connectivity – Passive NFC, tap-to-read via NXP NT3H2111 NFC tag
- Sensors – HDC2021 temperature and humidity sensors
- Measurement interval – 3 minutes to 65535 minutes (Default: 10 minutes)
- Battery – CR1220 battery (not included) good for an estimated 7+ years
- Power consumption – About ~1.5uA on average based on 10 minutes measurement interval achieve by remaining in LPM3 power modes most of the time.
Everything is open-source from the KiCad hardware design files to the MSP430 firmware and the cupldeploy web backend and frontend applications, all of which can be found on Github.
The cuplTag NFC sensor tag is available on Crowd Supply for $39 plus $8 shipping to the US and $18 to the rest of the world. If you’d like to change the board’s firmware a $153 MSP-FET Flash Emulation Tool appears to be required Rewards are expected to ship by the end of January 2022.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.