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Astrolamp Schematic Circuit Diagram

It takes up to an hour for our eyes to fully adapt to the dark and achieve maximum light sensitivity with the iris fully open. Astronomers use red light to avoid interfering with this adaptation process. A lamp for stargazing should also have several other features. Some of the features of the lamp described here are:

Astrolamp Schematic Circuit Diagram

Red and Dimmable Lighting Solution

In this lighting solution, a red light feature is implemented for observation, ensuring it is dimmable and user-friendly, even with gloves. Additionally, there’s a white light option for erecting and dismantling telescopes. To prevent operator errors, accidental activation of white light is eliminated. The existing lamps can be modified, and the lamp’s operation is streamlined with a single button control. Here’s how the button responds to different presses:

  • When the lamp is off, pressing the button for less than 5 seconds activates the red light.
  • When the lamp is off, pressing the button for more than 5 seconds switches on the white light.
  • If the red light is on, a press for less than 1 second turns off the lamp.
  • With the red light on, a press for more than 1 second adjusts the lamp’s brightness.
  • When the white light is on, a simple press turns off the lamp. Moreover, the lamp remembers the red light setting.

Remodeling Process and Circuitry

The starting point for this revamped lamp is an affordable headlamp from a DIY store, equipped with seven white LEDs and a water-resistant button. The lamp comprises a battery module holding three AAA cells (4.5 V) and features spring contacts and a control button. The remodeling involves replacing the original LED PCB and driver with the author’s circuitry, incorporating an ATtiny45 microcontroller, two diffuse red LEDs, and a salvageable white LED. To address the microcontroller’s limited output current, the white LED is connected to two pins. The firmware, available for download from the project’s webpage, is stored in the ATtiny45 microcontroller. Users can customize the program, and there is ample space for extensions due to the microcontroller’s available program memory.

Efficient Operation and Power Management

The values of resistors R1 to R3 can be tailored to match the forward voltages of the LEDs in use. Notably, the voltage drop across the microcontroller is negligible. The microcontroller exclusively handles lamp deactivation and operates in a low-power mode, drawing less than 1 µA according to the datasheet. This minimal power consumption aligns closely with the batteries’ self-discharge rate, ensuring efficient and prolonged usage. The microcontroller awakens when PB2 is grounded, typically occurring when the button is pressed.



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