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Forum Index : Microcontroller and PC projects : PicoMiteVGA - sound out
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PEnthymeme Regular Member  Joined: 27/12/2023 Location: United KingdomPosts: 42 |
Afternoon all In my attempt to build a countdown timer (LEDs sorted) - I am moving onto the audio aspect. The plan is for it to "tick" as it counts down and then play an "alarm". I am working using a 1second wav file of the "tick-toc" which is played as the LEDs countdown. And likewise an "alarm.wav" to play at the end. This part seems ok. Where I'm at is the PWM > Audio out. Two questions emerge: (1) What is the simplest filter to use - fidelity doesn't really matter (2) I want this to feed into powered speakers - will I be able to drive them directly or will I need an amplifier - have a few LM386 amp modules so could tinker with those. The other route is one of those "MP3" boards I see on my fav Chineese site - but that seems like overkill for my use case. The bigger plan is to hard code some default buttons - 1m, 2m, 5m, 15m on the countdown and bundle into a project box. Whilst I mention PicoMiteVGA - will probably be plain old PicoMite it the final version. Any pointers? Px |
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hitsware2 Guru  Joined: 03/08/2019 Location: United StatesPosts: 719 |
Simple R.C. should do ....... Will not need amp with powered speakers .. my site |
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| PEnthymeme Regular Member Joined: 27/12/2023 Location: United KingdomPosts: 42 |
Thanks for the sanity check! Px |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7912 |
Whatever you do, don't connect a low impedance load directly to an IO pin. I would suggest a resistor of 270R minimum to protect the pin. The simplest RC filter would probably be 1K series followed by 47nF to GND. Any load after that should total 1K or higher. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 2548 |
https://europe1.discourse-cdn.com/arduino/original/4X/c/8/3/c832b7cb1cea80815e33fc2eec0b67de3f37f8d2.jpeg |
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