Chhavi – An ESP32-based fingerprint sensor with optional NFC, battery (Crowdfunding)

Chhavi is a compact, wireless, touch-capacitive fingerprint sensor based on ESP32 WiFi and Bluetooth SoC that is offered with optional NFC connectivity and a battery.

The Arduino programmable fingerprint sensor is equipped with Fingerprints‘ FPC BM-Lite fingerprint capacitive biometric sensor that’s much more compact and power-efficient than traditional optical fingerprint sensors.

ESP32 Fingerprint sensorChhavi specifications:

  • SiP – ESP32-PICO-D4 system-in-package with ESP32 dual-core processor @ 240 MHz, 4 MB SPI flash
  • Fingerprint sensor
    • FPC BM-LITE Module with 99% accurate fingerprint sensing
    • Sensor matrix: 160 x 160 pixels
    • Number of pixels: 25,600 pixels
    • Active sensing area: 8 x 8 mm
    • Features – Automatic finger detection, one-to-one verification mode
    • Durability – 10 million finger placements
  • Connectivity
    • 2.4 GHz 802.11 b/g/n Wi-Fi via ESP32
    • Bluetooth BLE 4.2/5.x via ESP32
    • Optional 13.56 MHz NFC via NXP PN7150 NFC I2C controller
    • 3D antenna
  • Display – FPC connector for display
  • USB – 1x Micro USB port for power/charging, and debugging via CP2102 USB-to-UART converter
  • Misc – Power switch, reset button, vibration motor for haptic feedback, 2x user LEDs
  • Power Supply
    • 5V via micro USB port
    • Support for 250 – 500 MAh LiPo batteries
    • 600 mA, 3.3 V LDO regulator
    • ESD protection, over-voltage, over-current protection for USB
  • Dimensions – 26 x 26 x 9 mm (without battery)

Chhavi specifications: ESP32, Fingerprint, NFCThe company behind the project, Vicharak, will provide resources for Chhavi on Github. At this time, the repository only containing an Arduino sketch to display the fingerprint live data in a web browser.  The company will also release the Arduino library, and is working on a library compatible with the ESP-IDF framework as well.

Some of the use cases for Chhavi ESP32-based fingerprint sensor include signing in to a desktop computer, unlocking a password manager, implementing door locks and other physical security controls, attendance management systems, etc…

Vicharak has just launched Chhavi on Crowd Supply, which happens to be their second project on the crowdfunding platform after Maypole ESP32 wireless storage dongle. There are four rewards between $49 and $69 depending on the NFC and battery options adding $10 each. Shipping adds $8 to the US, and $20 to the rest of the world, and backers should expect their rewards to be shipped by February 2022.

Pricing is in line with other fingerprint solutions for makers, such as PiFinger Fingerprint HAT for Raspberry Pi, and one advantage is that a microcontroller, namely ESP32, is already included so a host system is not needed contrary to many other solutions as illustrated in the comparison table below.

Chhavi vs gt521f52 vs r301t fingerprint modules

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