Hi everyone!

I just wanted to share my recent MySensors project setup focused on indoor environment monitoring. I’ve been gradually building a home automation system, and MySensors has been a perfect fit for its flexibility and low power requirements.

Here’s a breakdown of my current configuration:

Sensor Node Configuration:
Microcontroller: Arduino Pro Mini 3.3V 8MHz (clone from HiLetgo)

Wireless Module: NRF24L01+ with 10µF capacitor for stability

Environmental Sensor: BME280 (https://www.ichome.com/product-detail/bosch-sensortec/bme280#PdfShow) for temperature, humidity, and pressure (connected via I2C)

Power: 2x AA batteries + step-up booster (using an HT7333 LDO for stable voltage)(https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/5057/HT73xx-A.pdf)

Additional Modules (planned):

BH1750 for ambient light sensing

TSL2561 as a more accurate alternative

Gateway Setup:
Controller: Home Assistant (via MySensors MQTT integration)

Gateway Type: MQTT Gateway

Hardware:

Arduino Nano + NRF24L01+

Connected to a Raspberry Pi 4B (4GB RAM) running Mosquitto MQTT Broker

Powering the gateway with USB + filtered 3.3V rail for NRF stability

🧠 Software:
MySensors Library Version: 2.3.2

Using the MySensors BME280 example sketch with slight modifications to add battery reporting (sendBatteryLevel()).

MQTT topics structured as: mysensors-out/0/1/1/0/0 etc.

Challenges & Solutions:
Interference: Had to add a 10µF electrolytic cap close to the NRF24L01+ VCC pin to prevent random disconnects.

Power Optimization: Removed voltage regulator & power LED from the Pro Mini, sleep cycles set to 10 minutes to save battery.

Signal Range: Improved range with a NRF24L01+ PA/LNA module and external antenna for the gateway.

Next Steps:
Integrating motion detection using HC-SR501(https://www.youtube.com/watch?v=QizfU7Fgmyw) PIR sensor

Adding OTA update capability via MYSBootloader (still exploring)

Possibly shifting to RFM69 for better range in multi-room setup

If anyone has experience optimizing BME280 accuracy or recommendations for better battery life, I’d love to hear your thoughts!