| Gas Sensor MQ-2 Gas/Smoke Detector | jemrf.com | 0.49 USD | 4.99 USD | −90.2% |
| MAX7219 8-Digit LED Display Module Digital Tube SPI Control Red | jemrf.com | 0.99 USD | 5.99 USD | −83.5% |
| Moisture Detection Sensor Module for Soil or Water for Arduino Raspberry Pi | jemrf.com | 0.85 USD | 3.49 USD | −75.6% |
| DIY Alarm Kit - Motion sensor, door contacts, temperature, buzzer siren | jemrf.com | 22.95 USD | 86.95 USD | −73.6% |
| Wireless Switch/Temperature Upgrade Kit | jemrf.com | 1.15 USD | 3.45 USD | −66.7% |
| Mini Breadboard 400 Point Prototyping Circuit board | jemrf.com | 2.59 USD | 6 USD | −56.8% |
| Magnetic Reed gap Switch N/C N/O Combined | jemrf.com | 4.5 USD | 10.4 USD | −56.7% |
| PIR Motion Sensor | jemrf.com | 1.67 USD | 3.75 USD | −55.5% |
| ESP32-C3-Zero Mini Development Board | jemrf.com | 3.95 USD | 8.49 USD | −53.5% |
| Waterproof DS18B20 Dallas 1 wire digital temperature sensor and resistor | jemrf.com | 2.95 USD | 7.95 USD | −50.4% |
| Capacitive Soil Moisture Sensor Module | jemrf.com | 1 USD | 2 USD | −50% |
| PL2303HX USB To RS232 TTL Auto Converter Module Converter Adapter For Raspberry Pi and Arduino | jemrf.com | 2.87 USD | 4.96 USD | −42.1% |
| Relay for Raspberry Pi or Arduino 1-Channel 5V Relay Module 250V/10A | jemrf.com | 5.95 USD | 9.99 USD | −40.4% |
| 5v Power Supply - 2.5A (Micro USB) | jemrf.com | 5.95 USD | 9.95 USD | −40.2% |
| Temperature Thermistr NTC 10K OHM 3977K (25 sensors) | jemrf.com | 8.89 USD | 14.59 USD | −39.1% |
| AM2320B (DHT22) External Digital Temperature and Humidity Sensor | jemrf.com | 6.99 USD | 9.99 USD | −30% |
| ESP32-C3 Super Mini Development Board WiFi+Bluetooth Ultra-Low Power | jemrf.com | 3.15 USD | 4.4 USD | −28.4% |
| ESP32-C3 Mini Development Board WiFi+Bluetooth Ultra-Low Power with Antenna | jemrf.com | 3.95 USD | 5.5 USD | −28.2% |
| USB 2.0 Cable Type A to Mini-B | jemrf.com | 2.85 USD | 3.79 USD | −24.8% |
| FT232RL FTDI USB 3.3V 5.5V to TTL Serial Adapter Module for Arduino Mini Port | jemrf.com | 6.95 USD | 8.95 USD | −22.3% |
| Wireless Developers Kit with Wireless Gateway | jemrf.com | 210 USD | 269.5 USD | −22.1% |
| Wireless Water Sensor Kit | jemrf.com | 19.95 USD | 24.95 USD | −20% |
| Soil Moisture Detect Probe 3 Meters | jemrf.com | 16 USD | 20 USD | −20% |
| Soil Moisture Detect Probe 1.3 Meters | jemrf.com | 9.95 USD | 12.43 USD | −20% |
| Wireless Analog Temperature Sensor | jemrf.com | 19.99 USD | 24.95 USD | −19.9% |
| Smart Gateway | jemrf.com | 190.99 USD | 285.99 USD | −19.1% |
| Wireless Temperature and Humidity Monitoring Kits with WiFi Wireless Gateway | jemrf.com | 99.95 USD | 118.8 USD | −15.9% |
| Business Starter Package | jemrf.com | 170 USD | 195 USD | −12.8% |
| WiFi Gateway Pro | jemrf.com | 49.95 USD | 59.95 USD | −12.3% |
| WIFI Waterproof Temperature Sensor Pro - Multiple External Sensors | jemrf.com | 34.25 USD | 64.75 USD | −12% |
| FT232RL FTDI USB 3.3V 5.5V to TTL Serial Adapter Module for Arduino USB-C | jemrf.com | 7.95 USD | 8.95 USD | −11.2% |
| WIFI Temperature and Humidity Sensor Pro Plus | jemrf.com | 34.95 USD | 54.95 USD | −11% |
| Wireless RF Starter Set | jemrf.com | 89.95 USD | 99.85 USD | −9.9% |
| WIFI Controlled Relay Switch Kit - Internet Of Things (IOT) | jemrf.com | 27.95 USD | 30.95 USD | −9.7% |
| Soil Moisture Detect Probe 5 Meters | jemrf.com | 14.95 USD | 16.56 USD | −9.7% |
| WIFI Waterproof Temperature Sensor - Multiple External Sensors | jemrf.com | 33.95 USD | 44.95 USD | −9.1% |
| WIFI Temperature and Humidity Sensor - Internet Of Things (IOT) | jemrf.com | 29.95 USD | 35.95 USD | −9.1% |
| WIFI Temperature and Humidity Sensor Pro | greenerharvestseeds.com | 32.95 USD | 50.45 USD | −7.9% |
| WIFI Temperature and Humidity Sensor Pro | jemrf.com | 32.95 USD | 50.45 USD | −7.9% |
| M-Series Wireless Temperature & Humidity Sensor | jemrf.com | 33.95 USD | 36.95 USD | −5.6% |