Low-Power Temp/Humidity Sensor Node
Thought for 5 sec
Work done
- Renamed the project and updated its description to match the approved Arduino temperature-indicator design.
- Created and populated the Project Specification with the architecture and implementation notes.
- Added U1, U2, U3, LCD1, R1, C1, and C2.
- Wired 5 V and GND to the sensor, LCD interface, and support parts.
- Connected Arduino I2C to the LCD interface: U1 SDA/SCL -> U3 SDA/SCL.
- Connected DHT22 data: U2 DATA -> U1 D2 with R1 as a 10k pull-up to 5 V.
- Added 100 nF decoupling with C1 and C2 across the 5 V rail.
- Mapped the LCD in 4-bit mode through U3: P0->RS, P1->E, P4->D4, P5->D5, P6->D6, P7->D7.
Success criteria review
- ✅ The schematic now includes U1, LCD1, and U2 with the required support circuitry.
- ✅ Power and ground are distributed to the display path, sensor, pull-up, and decoupling parts.
- ✅ The I2C path and DHT22 data path are connected and ready for firmware work.
- ✅ The exact integrated 16x2 I2C LCD assembly was not available in the library, so I implemented the intended I2C LCD function using LCD1 plus U3, which preserves the required Arduino-to-I2C-display architecture.
Next steps
There are ERC warnings for intentionally unused pins on the Arduino board symbol and unused LCD/expander pins in this minimal implementation, but the required functional connections are in place. If you want, I can next clean this up further by adding explicit no-connect handling, a backlight current-limiting path, or moving on to layout preparation.
Use D2 for DHT22
Add decoupling caps
Choose standard I2C pins
Add power connector
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