FlapAstro
AstroBin Instagram

All-Sky Camera

Built to watch
the whole sky.

A purpose-built camera system for continuous horizon-to-horizon imaging, with its own Windows computer and automatic dew-prevention controller.

Purpose-built system

Camera, computer,
and climate control.

The camera records the complete sky while a dedicated Intel NUC runs Windows and the all-sky capture software. A separate environmental-control system protects the optics from dew.

01

Imaging

ZWO ASI224MC

Wide-angle all-sky camera capturing the visible hemisphere above the observatory.

02

Computer

Intel NUC

A compact dedicated computer running Windows continuously at the camera.

03

Capture

AllSky software

Controls image acquisition and manages the continuous all-sky imaging workflow.

04

Environment

Sensor + Arduino

Temperature and humidity sensing, dew-point calculation, and variable-power heater control.

Automatic dew prevention

Heat only
when needed.

Rather than running at fixed power, the heater responds to changing atmospheric conditions. This reduces unnecessary heating while maintaining protection as the air approaches saturation.

  1. 01

    Sense

    A sensor measures ambient temperature and relative humidity.

  2. 02

    Calculate

    The control system calculates the current dew point from those readings.

  3. 03

    Assess

    The calculated dew risk is translated into the required heating level.

  4. 04

    Control

    An Arduino varies the heater’s power output instead of simply switching it fully on or off.

  5. 05

    Protect

    The heater keeps the exposed camera optics clear through changing night-time conditions.

Open-source controller

Build the monitor
and dew controller.

The Arduino firmware and Windows serial-monitor application used for this project are available in the FlapAstro GitHub repository. The package includes the source code, compiled Windows application, wiring guide, serial protocol, and known limitations.

View repository Download latest release

Hardware prerequisites

01

Controller

A classic Arduino Nano-compatible ATmega328P board and a data-capable USB cable.

02

Environment sensor

An external SHT31 or SHT35 I²C breakout, normally at address 0x44. Connect SDA to A4 and SCL to A5.

03

Heater driver

A correctly rated logic-level N-channel MOSFET, gate resistor and pull-down, fused heater supply, suitable wiring, and a common ground.

04

Windows computer

A Windows 10 or 11 computer with a free USB port and .NET Framework 4.7.2 or newer.

Arduino firmware

Compile and upload

  1. Install Arduino IDE, then add Adafruit SHT31 Library and its Adafruit BusIO dependency through the Library Manager.
  2. Open firmware/DewControlAllSkyCam/DewControlAllSkyCam.ino from the repository.
  3. Select Arduino Nano, the correct COM port, and the appropriate processor. Older clones may require ATmega328P (Old Bootloader).
  4. Confirm the sensor address is 0x44, or change it to 0x45 when required by the breakout.
  5. Upload the sketch and verify plausible temperature, humidity, dew-point, and PWM values in Serial Monitor at 9600 baud.

Windows application

Extract and run

  1. Download Arduino-Serial-Monitor-1.0.0.zip from the GitHub Releases page.
  2. Optionally compare its SHA-256 digest with the adjacent checksum file.
  3. Extract the ZIP into a writable folder; no installer or administrator access is required.
  4. Close Arduino IDE Serial Monitor so it releases the COM port, then run ArduinoSerialMonitor.exe.
  5. Let the application detect the Nano automatically, or select its COM port manually. The monitor reconnects when the device becomes available again.