CJMCU-6701 GSR Skin Sensor Module Analog SPI 3.3V/5V

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CJMCU‑6701 GSR SKIN SENSOR MODULE
(Analog & SPI | 3.3 V / 5 V COMPATIBLE)
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MODEL: CJMCU‑6701 GSR Skin Sensor Module
MODULE TYPE: Galvanic Skin Response (GSR) sensor
INTERFACES: Analog output + SPI digital interface
OPERATING VOLTAGE: 3.3 V or 5 V DC
SIZE: Approx. 33 × 18 × 7 mm (compact board):contentReference[oaicite:3]{index=3}

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📌 WHAT IT MEASURES:
• **Skin electrical conductance** (Galvanic Skin Response)
• GSR is a measure of **electrodermal activity (EDA)** — changes
in skin’s electrical properties due to sweat and arousal states.
• Useful for **stress responses, emotional tracking, biofeedback**.:contentReference[oaicite:4]{index=4}

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🔍 HOW IT WORKS:
• Two electrodes contact the skin.
• A small signal is applied through the skin.
• The module detects changes in skin **conductivity** —
these change with sweat gland activity related to emotional or
physiological arousal.
• Sensor outputs either an **analog voltage** proportional to
conductance or a **digital SPI data stream** for microcontrollers.:contentReference[oaicite:5]{index=5}

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📊 KEY SPECIFICATIONS:
• **ADC Resolution:** 12‑bit (high precision A/D conversion)
• **Sampling Rate:** ~100 ksps (fast response)
• Interfaces:
• **Analog output** — easily read by ADC input pins
• **SPI digital interface** — for precise, filtered data
• **Voltage compatibility:** accepts 3.3 V or 5 V logic and supply
• **PCB size:** ~33 mm × 18 mm × 7 mm (small form factor):contentReference[oaicite:6]{index=6}

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🧠 FEATURES & BENEFITS:
• **Dual interface (Analog + SPI):** Integrates with many
microcontrollers and systems.:contentReference[oaicite:7]{index=7}
• **Wide voltage support:** Works with both 3.3 V and 5 V boards
(e.g., Arduino, ESP32, Raspberry Pi via logic conversion).:contentReference[oaicite:8]{index=8}
• **High sensitivity:** Many physiological changes are detectable.:contentReference[oaicite:9]{index=9}
• **Compact & lightweight:** Easy to embed in wearables.:contentReference[oaicite:10]{index=10}

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📈 COMMON APPLICATIONS:
• **Stress & emotion monitoring** (biofeedback)
• **Wearable health devices**
• **Human‑computer interaction systems**
• **Research in psychology, physiology, UX studies**
• **Lie detection / polygraph experiments**:contentReference[oaicite:11]{index=11}

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🔌 INTERFACING HIGHLIGHTS:
• **Analog mode:** connect the analog output to MCU’s ADC pin
(use proper voltage level range).:contentReference[oaicite:12]{index=12}
• **SPI mode:** connect SCLK, MOSI/MISO, CS to MCU for digital
readings (more robust data).:contentReference[oaicite:13]{index=13}
• Always share **common ground** between sensor and controller.:contentReference[oaicite:14]{index=14}

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🧠 USAGE TIPS:
• Good skin contact is essential — electrodes must touch skin.
• If using SPI, use correct tempo and logic levels.
• Keep sensor dry and avoid corrosion on electrodes.
• Use shielding/grounding where needed to reduce noise.