The Pill by Shelly

Device identification
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Device name: The Pill by Shelly
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Device model: S3SN-0U53X
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Device SSID: ShellyPill-XXXXXXXXXXXXXX
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Bluetooth ID: 0x1829
Short description
The Pill by Shelly is a compact multi-purpose low-voltage Wi-Fi & Bluetooth device, powered by only 5V via USB-C. The small form factor allows it to fit conveniently into any space-constraint environment.
The device is ready to use for Temperature monitoring with Plug and play compatibility with external Temperature sensors (DS18B20) or Temperature & Humidity (DHT22). Additionally, supporting wide variety of digital or analog sensors and low-voltage actuators with external peripheral addons and configurable peripheral modes.
Main features
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Compact design
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USB-C powered (5V)
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Dual connectivity (WiFi & Bluetooth)
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Plug and play: Temperature monitoring (DS18B20/DHT22)
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Advanced peripheral modes - Digital Input/Output; Analog input (Voltage meter);
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External Peripheral Add-ons: SSR Dual-channel, Analog Voltage measurement (0-30V)
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Shelly Gen3 capabilities (Local actions, Schedules, Scripting, Virtual components)
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Bluetooth Gateway for Shelly BLU devices
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3rd party integrations-ready (MQTT, WebSocket, HTTP)
Peripheral modes
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Temperature (DS18B20) - Supporting up to 5 x Temperature probes (DS18B20); + optional 2 Digital IO
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Temperature & Humidity - 1x Temperature & Humidity sensor DHT22 + optional 2 Digital IO
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Analog Input - Analog sensor input (voltmeter) + optional Digital IO. Measured Voltages: 0-2.5 V (default); external Add-on for 0-30V
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Digital Input/Output - configurable for up to 3x Inputs/Outputs ; Digital IO: 3.3 V Logic Levels; Digital input: Active Low (default).
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Solid State Relay Add-on - Peripheral Addon with 2x channels galvanic-isolated outputs (max 30 V / 300 mA) + optional Digitial IO
* Note: Digital I/O can be combined with all modes and setup independently as Input or Output
Use cases
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Water Temperature Monitoring
Track temperature of pools, aquariums, water tanks and reservoirs with simultaneous monitoring of up to five temperature points, using external temperature sensor probes (DS18B20) -
Temperature and Humidity Monitoring
Monitor temperature and humidity in a room, server cabinets, greenhouse, warehouses or other areas where keeping optimal environment condition is necessary, with the supported external sensor DHT22 -
Digital Sensors Readings
Connect simple digital sensors like door reed, motion, water state sensor to your home automation system -
DC Voltage monitoring - external Add-on available
Monitor DC voltages up to 30 V with the external Analog 0-30 V Add-on, suitable for tracking voltage across various battery systems (3.7 V, 12 V, 24 V) or other DC power lines. -
Analog Sensor measurements - external Add-on available
Analog sensor voltage measuring for popular hobby & industrial analog sensors with the available Analog 0-30 V Add-on -
Control DC Loads - external Add-on available
Dual-channel control for small DC Loads up to 30 V / 300 mA like led indicators, small fans, solenoids, valves and etc. with additionally available external SSR Add-on -
External Systems Control
Available Digital Input/Outputs allow switching and reading state of external controllers and systems (3.3V logic level). The optionally available SSR Add-on allows triggering inputs of external controllers (max 30 V / 300 mA).
Main applications
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Residential
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University/college
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Hobby
Integrations
…
Simplified internal schematics

Device electrical interfaces
Power supply
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USB-C power supply: +5 V⎓
Add-on interface
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DC Power Supply: +5 V⎓
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Input/Output 1 - Configurable:
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1-Wire (DS18B20, DHT22)
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Digital Input
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Digital Output
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Analog Input (Voltmeter)
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Input/Output 2 - Configurable:
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Digital Input
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Digital Output
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Input/Output 3 - Configurable:
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Digital Input
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Digital Output
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GND
Connectivity and protocols
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Wi-Fi
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Bluetooth
User interface
Inputs
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One (Control) button
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Press and hold for 5 seconds to enable Device access point and Bluetooth connection.
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Press and hold for 10 seconds to factory reset the Device.
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Outputs
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LED (monocolor) indication
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AP (Access Point) enabled and Wi-Fi disabled:
1 secondON/ 1 secondOFF -
Wi-Fi enabled, but not connected to a Wi-Fi network:
1 secondON/ 3 secondsOFF -
Connected to a Wi-Fi network:
ConstantlyON -
Cloud is enabled, but not connected:
1 secondON/5 secondsOFF -
Connected to Shelly Cloud:
ConstantlyON -
OTA (Over the Air Update):
½ secON/ ½ secondOFF -
Button pressed and held for 5 seconds:
½ secondON/ ½ secondOFF -
Button presses and held for 10 seconds:
¼ secondON/ ¼ secondOFF
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The list above starts with the initial device status and the lowest priority. Every next state cancels the previous one.
Specifications
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Quantity |
Value |
|---|---|
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Physical |
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Size (HxWxD): |
26 x 19.95 x 8.5 mm / 1.02 x 0.79 x 0.34 inch |
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Weight: |
3 g / 0.11 oz |
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Shell material: |
Plastic |
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Shell color: |
White |
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Environmental |
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Ambient working temperature: |
-20 to 40 °C / -5 to 105 °F |
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Humidity: |
30 % - 70 % RH |
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Electrical |
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Power supply: |
5 V⎓ (from USB Type-C port) |
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Power consumption: |
< 1 W |
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Input circuits ratings |
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Digital inputs triggering voltage: |
Active LOW; Trigger low: < 0.83 V Trigger high: > 2.48 V |
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Digital inputs max. voltage |
3.3 V |
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Output circuits ratings |
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Max. switching voltage: |
3.3 V (logic-level) |
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Max. switching current: |
20 mA |
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Sensors, meters |
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Voltmeter (DC) |
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Voltmeter accuracy: |
±(2% + 5d) |
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Internal-temperature sensor: |
No |
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External sensors supported: |
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Radio |
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Wi-Fi |
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Protocol: |
802.11 b/g/n |
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RF band: |
2401 - 2483 МHz |
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Max. RF power: |
< 20 dBm |
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Range: |
Up to 30 m / 100 ft indoors and 50 m / 160 ft outdoors (Depends on local conditions) |
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Bluetooth |
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Protocol: |
BLE 4.2 |
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RF band: |
2402 - 2480 МHz |
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Max. RF power: |
< 10 dBm |
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Range: |
Up to 10 m / 33 ft indoors and 30 m / 100 ft outdoors |
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Microcontroller unit |
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CPU: |
Shelly ESP32 C3 (ESP-Shelly-C38F) |
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Flash: |
8MB |
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Firmware capabilities |
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Schedules: |
20 |
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Webhooks (URL actions): |
20 with 5 URLs per hook |
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Scripting: |
Yes |
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MQTT: |
Yes |
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Encryption: |
Yes |
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Other: |
Supported Accessories:
Supported add-ons:
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Components and APIs
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This device
Compliance
The Pill by Shelly multilingual EU declaration of conformity 253 2025-12-11.pdf
The Pill by Shelly UK PSTI ACT statement of compliance 253 2025-12-11.pdf
The Pill by Shelly UKCA declaration of conformity 253 2025-12-11.pdf
Printed user guide
The Pill by Shelly multilingual printed user and safety guide.pdf