Is there a low-cost, less annoying alternative to a buzzer or LED for displaying the status of an operation? I want my clock radio on at night, but it has this really annoying power indicator LED. I'd like to keep some form of power indicator, so replacing the LED with an equivalent diode or just removing it isn't an option, but I also need to have it on. I have the LED removed, I just need some non-irritating indicator that I can still check if I want to, but without emitting any light.
One indicator variety not mentioned in the other answer is flip-dot indicator: http://www.flipdots.com/electromagnetic-status-indicators.html
Those had been around for ages, and can easily be considered the most non-annoying indicator around, as they don't emit any light but are still perfectly readable under moon light conditions.
Essentially, you'd like to know the status of the clock, when you need to. But, you don't want to see the LED when you don't need to.
- Add a momentary switch in series with LED. When you want to check the status, you can press the button and see the LED.
- The LED should have a series resistor. Increasing the value of the resistor would dim the LED and make it less annoying, possibly.
- Solenoid and spring as indicator. When the power is present, the solenoid is energized. When the power is not present and the solenoid is not energized, the spring pushes the armature out. The armature of the solenoid becomes an indicator.
- Tape the LED over. When you want to check the status, peel back the tape. Put the tape back, when you're done.
- Connect an electromagnet instead of the LED. When the LED is on, the electromagnet is energized. The electromagnet is holding a steel ball. Directly under the ball is a metal bowl, such that the ball will make loud noise when it falls. Julius Caesar style.
- Yoga. The LED will seem less irritating, as might lots of other things.