Pololu QTR-MD-04RC Reflectance Array - 4-Channel, 8mm Pitch single digit The WiFi Bee ESP8266 is

The WiFi Bee ESP8266 is a Serial-to-WiFi module in the standard XBee form factor

You can also compare it with Linear Guide Slide Rail 12mm wide 300mm long

Current draw: 33 mA4

5 without headers Main MCU ARM Cortex-M4 Clock Speed 120 MHz Memory 512 KB Flash

input voltages above 4

Pololu QTR-MD-04RC Reflectance Array - 4-Channel, 8mm Pitch single digit The WiFi Bee ESP8266 isDetect Nearby Objects Without Contact The Reflectance Sensor Array QTR MD 04RC 4 Channel 8mm Pitch RC Output is an optical interrupter sensor with digital output designed for obstacle detection, touchless triggers, object counting, and simple automation. It is a practical fit for makers, students, and engineers who want reliable sensor data in embedded builds. Key details include Operating voltage: 2. 9 V to 5. 5 V. Why youll love it Useful spec: QTR