ESP32CAM-Weather-Station

Electronics

This project uses a custom weather-station PCB that combines power management, protection, and an I2C sensor/expansion bus.

Power features

• Supports battery input with input protection.
• Supports solar input with surge/transient protection.
• Includes battery charging (status indicators and a battery temperature/thermistor input).
• Provides regulated rails for the rest of the system (including a 3.3V rail for sensors/logic).
• Breakouts/headers for accessing power rails (battery and regulated output) for debugging or external loads.

Measurement & sensing features

• On-board sensing for battery voltage and solar/charging voltage.
• On-board environmental sensing (temperature/humidity/pressure/gas resistance).
• On-board gas sensing (VOC/NOx measurements).
• On-board ambient light sensing (lux).
• ESP32-CAM on-board sky camera.

I2C bus + expansion features

• I2C bus includes pullups and ESD/transient protection.
• Multiple external I2C expansion headers (3.3V / GND / SDA / SCL) for additional sensors.

Extras

• A PCB that makes the board compatible with the Raspberry Pi Pico (Original or W or 2 or 2W) is also included in the design files.

Media (photos and design files)

Photos below are from testing / bring-up and may show temporary wiring or rework.

PCB front (testing photo)

PCB back (testing photo)

KiCad PCB layout (screenshot)

Schematic (export image)

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Mechanical design (placeholder)

• TODO: enclosure details, mounting, weatherproofing, cable glands, venting strategy, sensor placement.
• TODO: 3D print files / CAD links, tolerances, and assembly steps.
• TODO: photos/diagrams.

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Software: Pico Weather Station (Client) + Local Ingest Server (HTTP + HMAC)

This project consists of:

• Client (Raspberry Pi Pico 2 W): reads sensors over I2C and periodically posts measurements to a server.
• Server (Python): accepts measurements over HTTP and protects the endpoint with:
  • Bearer token allow-list (multiple devices supported)
  • HMAC-SHA256 request signature (fast reject of unauthenticated spam)
  • Rate limiting (per IP and per token)
  • Max body size and max concurrency
  • CSV logging to two files (same schema)

Security note: This design does not encrypt the data in transit (it is HTTP). It does prevent unauthorized clients from successfully sending data (and helps prevent trivial overload). If you need confidentiality, use HTTPS.

Repository layout (recommended)

PlatformIO (client)

• src/measurement_post_requests.cpp (or src/main.cpp) — client code
• include/client_config.h — user-created (not committed)
• include/wificredentials.h — user-created (not committed)

Server (Python)

• server/server_config.py
• server/server_http_hmac.py

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1) Server setup (Python)

1.1 Requirements

• Python 3.9+ recommended (stdlib only)

No pip packages required.

1.2 Files

Create a directory (example):

server/
  server_http_hmac.py
  server_config.py

1.3 Configure server_config.py

Key options:

• Bind / endpoint: HOST, PORT, INGEST_PATH
• Auth: AUTH_TOKENS, ALLOW_BEARER_HEADER
• Protections: REQUIRE_HMAC, REQUIRE_TIMESTAMP, RATE_LIMIT_*, MAX_BODY_BYTES, MAX_CONCURRENT_REQUESTS
• CSV: CSV_PATH_1, CSV_PATH_2, CSV_HEADER

If you are not setting time on the Pico (no NTP), set REQUIRE_TIMESTAMP = False.

1.4 Run the server

From the server/ directory:

python3 server_http_hmac.py

1.5 Test health endpoint

curl http://<server-ip>:<port>/health

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2) Client setup (PlatformIO / Pico 2 W)

2.1 Create user config headers (required)

Create these two files under the PlatformIO include directory:

• include/client_config.h
• include/wificredentials.h

These should not be committed (they contain secrets).

include/wificredentials.h

#pragma once

#define WIFI_SSID "YOUR_WIFI_SSID"
#define WIFI_PASS "YOUR_WIFI_PASSWORD"

#define USE_STATIC_IP 1

#if USE_STATIC_IP
  #define WIFI_LOCAL_IP   IPAddress(192,168,2,55)
  #define WIFI_DNS_IP     IPAddress(1,1,1,1)
  #define WIFI_GATEWAY_IP IPAddress(192,168,2,1)
  #define WIFI_SUBNET_IP  IPAddress(255,255,255,0)
#endif

include/client_config.h

#pragma once

#define DEVICE_ID "pico2w-01"
#define SERVER_URL "http://192.168.2.8:8080/ingest"

// Token secret: must exist in server_config.AUTH_TOKENS
#define AUTH_TOKEN "CHANGE_ME_TO_A_LONG_RANDOM_SECRET"

#define POST_INTERVAL_MS 1000
#define HTTP_TIMEOUT_MS 5000