Input Devices

Tools

SAMD11

Custom board

Debugging & Measurement

It’s a voltage divider configuration formed by the LDR and a 10 kΩ resistor. The system converts light intensity into variations in voltage. The output signal is taken from the midpoint and connected to the signal pin.

The photoresistor module (HW-483) uses an LDR that varies its resistance according to the incident light intensity. The board includes a resistor for signal conditioning and provides 3 pins: VCC, GND, and S (signal output).

The microphone, biased with a 10 kΩ resistor, converts sound into a low-amplitude analog signal that is filtered and conditioned. This signal is then compared against a reference voltage adjustable through a 10 kΩ potentiometer, generating an analog output (AO) proportional to the sound level (0–VCC, 3.3–5 V) and a digital open-collector output (DO) that is triggered when the threshold is exceeded, including pull-up resistors and a two-state indicator LED.

The module also integrates an operational amplifier and a potentiometer used to adjust sensitivity.

We soldered the components in order to perform tests using the SAMD11, while also using a multimeter to verify that the connections were correct.

I connected my SAMD11 to the PCB and processed sound intensity data in real time. In my case, I used these sensors together with the board developed in week 9, allowing me to integrate the signal acquisition system and evaluate the sensor’s behavior within a custom embedded architecture.

The LDR is connected to the same custom PCB. The module detects variations in ambient light and generates an analog signal through the signal pin.