Sound Card Driven Servo Motor

May 26, 2010 by 14 Comments

[youtube=http://www.youtube.com/watch?v=1LG2Ecsk13Q]

[Darrell] is using a sound card to drive this servo motor. The motor draws power from a cellphone battery with the control signal coming from one of the audio channels. It’s not too surprising that this works since the motor just needs a PWM signal to operate and that’s what is used to create the different frequencies of sound on electronic speakers. We’re not sure what [Darrell’s] got planned for this system but he mentions that two servos can be used, one on each audio channel. If you’re not using your sound card this would be a way to stop using the Arduino for that mail checker and just use a little flag attached to a servo. When mail comes in the appropriately engineered sound raises the flag.

Make An ECG With Your Sound Card

May 26, 2008 by 6 Comments


[Marcus] sent in his work on making ECGs. His first one was inspired by [Jason]’s. Believe it or not, you can build this thing for under $5. After getting it semi-functional, he decided to pick up a cheap one and mod it for PC input via the sound card. (There are plenty of sound card oscilloscope projects that will work for this.) Remember kids, don’t go sticking electrodes on anyone unless you know what you’re doing: correctly placed electrical shocks (even low power ones) can be deadly.

Connecting DECT Phones Through Sound Cards For Asterisk

October 8, 2005 by 10 Comments

board

I couldn’t think of a better title. Here’s how it goes: [onno] wanted to convert a DECT phone for VOIP use. First he tried using transformers for the audio, but was unhappy with the noise and echo. He describes how to do a direct tap like [Christoffer]’s Skype phone, but includes all of the necessary measures to keep from frying your sound card. The main piece of this project is his hacked “chan_oss” driver for Asterisk. Using the driver, Asterisk is able to ring the DECT phone. It also detects whether the phone is off-hook by comparing the sound input to the known line noise level. The phone can dial using DTMF just like any standard phone.

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Reviving A Scrapped Sound Blaster 2.0 ISA Soundcard

September 22, 2025 by 7 Comments

What do you do when you find a ISA Sound Blaster 2.0 card in a pile of scrap? Try to repair the damage on it to give it a second shot at life, of course. This is what [Adrian Black] did with one hapless victim, with the card in question being mostly in good condition minus an IC that had been rather rudely removed. The core Creative CT1336A and Yamaha YM3812 ICs were still in place, so the task was to figure out what IC was missing, find a replacement and install it.

The CT1350 is the final revision of the original 8-bit ISA Sound Blaster card, with a number of upgrades that makes this actually quite a desirable soundcard. The CT1350B revision featured here on a card from 1994 was the last to retain compatibility with the C/MS chips featured on the original SB card. After consulting with [Alex] from the Bits und Bolts YT channel, it was found that not only is the missing IC merely an Intel 8051-based Atmel MCU, but replacements are readily available. After [Alex] sent him a few replacements with two versions of the firmware preflashed, all [Adrian] had to do was install one.

Before installation, [Adrian] tested the card to see whether the expected remaining functionality like the basic OPL2 soundchip worked, which was the case. Installing the new MCU got somewhat hairy as multiple damaged pads and traces were discovered, probably because the old chip was violently removed. Along the way of figuring out how important these damaged pads are, a reverse-engineered schematic of the card was discovered, which was super helpful.

Some awkward soldering later, the card’s Sound Blaster functionality sprung back to life, after nudging the volume dial on the card up from zero. Clearly the missing MCU was the only major issue with the card, along with the missing IO bracket, for which a replacement was printed after the video was recorded.

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Ancient SoundBlaster Cards Just Got A Driver Update

June 28, 2025 by 11 Comments

Old hardware tends to get less support as the years go by, from both manufacturers and the open-source community alike. And yet, every now and then, we hear about fresh attention for an ancient device. Consider the ancient SoundBlaster sound card that first hit the market 31 years ago. [Mark] noticed that a recent update squashed a new bug on an old piece of gear.

Jump over to the Linux kernel archive, and you’ll find a pull request for v6.16-rc3 from [Takashi Iwai]. The update featured fixes for a number of sound devices, but one stands out amongst the rest. It’s the SoundBlaster AWE32 ISA sound card, with [Iwai] noting “we still got a bug report after 25 years.” The bug in question appears to have been reported in 2023 by a user running Fedora 39 on a 120 MHz Pentium-based machine.

The fixes themselves are not particularly interesting. They merely concern minutiae about the DMA modes used with the old hardware. The new updates ensure that DMA modes cannot be changed while the AWE32 is playing a PCM audio stream, and that DMA setups are disabled when changing modes. This helps avoid system lockups and/or ugly noises emanating from the output of the soundcard.

It’s incredibly unlikely this update will affect you, unless you’re one of a handful of users still using an ISA soundcard in 2025. Still, if you are — and good on you — you’ll be pleased someone still cares about your user experience. Meanwhile, if you’re aware of any other obscure old-school driver updates going on out there, don’t hesitate to let us know on the tips line. Want to relive your ISA card’s glory days? Plug it into USB.

Image credit: Gona.eu, CC BY-SA 3.0

[Thanks to Meek Mark for the tip!]

A solar-powered decibel meter the size of a business card.

2024 Business Card Challenge: NoiseCard Judges The Sound Around You

June 22, 2024 by 6 Comments

Let’s face it: even with the rise of the electric car, the world is a noisy place. And it seems like it has only gotten worse in recent years. But how can we easily quantify the noise around us and know whether it is considered an unhealthy decibel level?

That is where the NoiseCard comes in. This solar-powered solution can go anywhere from the regrettable open office plan to the busy street, thanks to a couple of 330 µF capacitors. It’s based on the low-power STM32G031J6 and uses a MEMS microphone to pick up sound from the back of the card, which the code is optimized for. Meanwhile, the LEDs on the front indicate the ambient noise level, ranging from a quiet 40 dB and under to an ear-splitting 105 dB or greater.

When it comes to building something the size of a business card, every component is under scrutiny for size and usefulness. So even the LEDs are optimized for brightness and low power consumption. Be sure to check it out in action after the break in various environments.

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The STM32 Makes For A Cheap DIY USB Soundcard

May 24, 2022 by 14 Comments

Soundcards used to be giant long 8-bit ISA things that would take up a huge amount of real estate inside a desktop computer. These days, for most of us, they’re baked into the motherboard and we barely give them a second thought. [Samsonov Dima] decided to whip up a cheap little sound card of their own, however, built around the STM32.

The soundcard is based specifically on the STM32F401. readily available on the “Green Pill” devboards. A digital-to-analog converter is implemented on the board based on two PWM timers providing high-quality output. There’s also a simulated software sigma delta ADC implemented between the audio streaming in via USB and the actual PWM output, with some fancy tricks used to improve the sound output. [Samsonov] even found time to add a display with twin VU meters that shows the audio pumping through the left and right channels.

Without test gear on hand, we can’t readily quantify the performance of the sound card. However, as per the Youtube videos posted, it appears more than capable of recreating music with good fidelity and plenty of fine detail.

If you need a cheap, simple USB sound card that you can hack away on, this might be the one for you. If you need something more suitable for a vintage PC, however, consider this instead. Video after the break.

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