PLT-1 Ultimate Plant Sensor

The Apollo Automation PLT-1 is an ESP32-C3-based  indoor plant multisensor that measures soil moisture (capacitive), air temperature, humidity, LUX, and UV, which can be used with Home Assistant via ESPHome!

It also features an onboard piezo buzzer and addressable RGB LED. Soil temperature can be measured using the optional temperature probe add-on. The sensor comes in a battery or non-battery version, with the non-battery (USB-C powered, 5V 1A) version being significantly smaller – select an option before adding to your cart.

The PLT-1 uses a capacitive soil moisture sensor, which offers much better accuracy and durability compared to resistive sensors. Additionally, the ground contact portion is protected with a conformal coating, ensuring longevity and resistance to environmental factors.

Both versions of the PLT-1 come with a 3D printed case.

Note: The PLT-1B (battery version) does not include a battery or charger. You will need to source their own rechargeable 18650 batteries for the battery version, and a charger. Battery life is estimated at 6 months based on a quality rechargeable 18650 and the default sleep / wake settings.

Features

• ESP32-C3-Mini based: ESPHome compatible, allowing plant monitoring in HomeAssistant
• Capacitive Soil Moisture Sensor with conformal coating: Accurate and durable, perfect for monitoring plant hydration
• AHT20-F Air Temperature & Humidity Sensor: Dust-protected for reliable air condition tracking
• LTR390 UV & LUX Sensor: Measures light and UV exposure, ensuring optimal lighting for plants
• RGB LED: Customizable for notifications (e.g., watering alerts, light levels)
• Piezo Buzzer: Provides audible alerts for important plant care events
• Battery and Non-Battery Versions: Flexible power options to suit different setups and needs
• Home Assistant Integration: Easily automate and monitor plant health through your smart home system
• Can be used with an optional DS18B20 Waterproof Soil Temperature Probe: Monitors soil temperature with precision

Use Cases

• Automated Watering: With its capacitive soil moisture sensor, you can set up automations to water plants only when moisture levels drop below a certain threshold.
• Optimising Sunlight Exposure: Use the LUX and UV sensors to monitor light levels, ensuring your plants get the right amount of sunlight. Automate window shades or grow lights based on current light conditions.
• Temperature & Humidity Management: Track air temperature and humidity with the AHT20-F sensor, adjusting indoor climate controls (like fans, heaters, or humidifiers) to maintain ideal growing conditions.
• Soil Temperature Monitoring: Use the optional waterproof soil temperature probe to monitor and control soil warmth for temperature-sensitive plants, especially in colder months.
• Visual & Audio Alerts: The RGB LED can be programmed for visual notifications, such as turning red when soil is dry or green when conditions are optimal. The piezo buzzer can alert you if immediate action is needed.

Community Reviews

• Simon Says Home Assistant PLT-1 Review
• Michael Leen PLT-1 Review
• Mostly Chris PLT-1 Review

Resources

Documentation

• Apollo Automation PLT-1 Wiki
• PLT-1 GitHub Repo
• OpenPlantbook integration for Home Assistant

Datasheets

• AHT20-F
• LTR390

3D Print Files

• 3D Case File

Apollo Automation Social

• Discord
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• TikTok

Package Contents

• Assembled PLT-1 sensor with 3D printed case
  • Select a version before adding to your cart

Batteries, charger and USB cable not included.