Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: rbowman Newsgroups: comp.os.linux.misc Subject: Re: Anybody Seen a Simple LED "Fail-Over" Circuit ? Date: 26 Nov 2024 08:40:25 GMT Lines: 24 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Trace: individual.net oh7h/TngrYHynvOHwsA85QYKYYQflv7sv7ww2vwzEqdHUBp0SX Cancel-Lock: sha1:5CNhgV50yAwc+82+d/BTV5iVwLg= sha256:24O+nq8AXnamAuCLk9Jd2PQTLSNLbtv/lyzVYIDY174= User-Agent: Pan/0.149 (Bellevue; 4c157ba) Xref: csiph.com comp.os.linux.misc:61368 On Tue, 26 Nov 2024 02:24:12 -0500, 186282@ud0s4.net wrote: > Critical Redundancy - One LED fails, another takes over ? Complicated question. For a complete catastrophic failure where the LED is either open or shorted a couple of transistors might do it. Even that would be difficult if a PWM dimmer is used. Even worse the degradation may be light output and/or color rather than a simple go / no go. Then you get into the human part of the equation: https://learn.sparkfun.com/tutorials/light/visible-light I'd actually been playing with PWM output in a Pico with C. The Uno piles a lot of sugar on it with analogWrite rather than the Pico SDK hardware_pwn https://cec-code-lab.aps.edu/robotics/resources/pico-c-api/ group__hardware__pwm.html I've got to play with it a little more but simply incrementing the duty cycle isn't too smooth perceptually.