Yet another DIY Wifi IoT WTF thermostat, made of 3 modules: A base module which communicates with the other modules, implements the control logic and has internet connectivity. A wireless temperature/humidity sensor. A wireless heater activation relay.
Here are its base features:
- Arduino based
- Wireless heater relay and thermal probe
- Base module uses a DS3231 RTC for timekeeping
- Uses NRF24L01+ modules for wireless communication between modules
- Uses the Blynk API for easy smartphone control
- 7 days program with 30 minutes granularity (48 daily slices)
- 2 temperature zones
Here are its advanced features:
- Wireless temperature probe built inside a Pesto Novella jar
- Ultra low power design of the thermal probe module, it runs on 2xAA batteries, 50uA idle current, 6mA peak when transmitting, once every 16 seconds
- Monitoring of probe battery voltage
- Monitoring of radio connection status
- Thermostat daily program saved inside the ESP8266’s SPI flash
- Overly complicated and unfriendly web interface for daily program setting
- Programmable hysteresis
Here is the bill of materials:
Base module:
- 4€ NodeMCU 1.0
- 2€ 128×32 SSD1306 I2C OLED display
- 2.5€ DS3231 RTC module
- 1.5€ NRF24L01+ module
- 1€ PCF8574 I/O expander for the RGB LED and maybe some buttons in the future
- 4€ 60x80mm proto board
Temperature probe module:
- 2€ Arduino pro mini 3.3V 8MHz (clone)
- 1.5€ NRF24L01+ module
- 2€ 2xAA battery holder
- 3€ 40x40mm proto board
- 1€ DHT22 temperature/humidity sensor
- 2.99€ Pesto Novella plastic jar (130gr)
Heater activation relay module:
- 2€ Arduino pro mini 5V 16MHz (clone)
- 1.5€ NRF24L01+ module
- 1€ ULN2004 driver for relay
- 1€ 5v coil relay
- 3€ 40x40mm proto board
- ??€ Old USB phone charger as power supply
- 1.6€ Plastic box