Low-pass filter for audio out

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yves1984
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Re: Low-pass filter for audio out

Post by yves1984 » Fri May 13, 2016 1:03 am

i saw the usb audio idee from chiz. think i will do like him ;)

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1461748123
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Re: Low-pass filter for audio out

Post by 1461748123 » Sun May 15, 2016 1:35 am

I've successfully completed the filter for audio out
Here is the prototype:
Image

The finished product:
Image
Image

I will post a full tutorial soon

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chiz
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Re: Low-pass filter for audio out

Post by chiz » Sun May 15, 2016 2:08 am

Popcorn wrote:Can someone please tell me again why we just aren't using a $1 USB sound adapter? Seems like we are reinventing the wheel that is on the cart before the horse. :D
I agree with Popcorn here. I didn't reply until someone mentioned about using USB audio adapter as the topic is about using a filter for PWM.

I'm a proponent of using USB audio to the following reasons:
1. it's an audio filter and amplifier in one
2. it's easy to configure the system to use USB audio
3. cheap

See how small a USB audio adapter can be:

Image

Downside is you use one additional USB connection. However, I think from a day-to-day use case standpoint, one will require at least two USB connections: 1) Teensy for the controller, and 2) USB audio for sound.

The third USB connection is for the external USB port which will allow one to add another USB hub to connect a Bluetooth dongle, wi-fi dongle, USB keyboard, mouse (and what have you) for the occasional system tweaking and file copying. I doubt you'll need all of these additional peripherals everyday. Unless I'm missing something here. Besides, if you put a lot of USB devices attached simultaneously, that adds to the power drain.

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Re: Low-pass filter for audio out

Post by 1461748123 » Sun May 15, 2016 2:15 am

chiz wrote:
Popcorn wrote:Can someone please tell me again why we just aren't using a $1 USB sound adapter? Seems like we are reinventing the wheel that is on the cart before the horse. :D
I agree with Popcorn here. I didn't reply until someone mentioned about using USB audio adapter as the topic is about using a filter for PWM.

I'm a proponent of using USB audio to the following reasons:
1. it's an audio filter and amplifier in one
2. it's easy to configure the system to use USB audio
3. cheap

See how small a USB audio adapter can be:

Image

Downside is you use one additional USB connection. However, I think from a day-to-day use case standpoint, one will require at least two USB connections: 1) Teensy for the controller, and 2) USB audio for sound.

The third USB connection is for the external USB port which will allow one to add another USB hub to connect a Bluetooth dongle, wi-fi dongle, USB keyboard, mouse (and what have you) for the occasional system tweaking and file copying. I doubt you'll need all of these additional peripherals everyday. Unless I'm missing something here. Besides, if you put a lot of USB devices attached simultaneously, that adds to the power drain.
I'm using PWM because I need more usb ports :D..
I got a 4 port hub, one goes to teensy, one goes to external, one to Bluetooth and one for wifi. I really don't have any other options beside PWM.
PS. I'm not building my GBZ just for gaming LOL

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Re: Low-pass filter for audio out

Post by chiz » Sun May 15, 2016 2:28 am

@1461748123
[off-topic]
Ok I recall now... You'll be using the GBZ as a portable hacking device, correct? This is interesting and I could be missing a lot of potential for this. Care to point me to a website where I can get all the information I need to know about a portable hacking device?
[/off-topic]

Edit: Ok. So a quick googling led me to "Kali Linux". I guess I'll start from there.

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1461748123
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Re: Low-pass filter for audio out

Post by 1461748123 » Sun May 15, 2016 2:33 am

@chiz
I'm actually not following any guides, just using my previous knowledge to make it work :D
But this should help: http://lifehacker.com/how-to-build-a-po ... 1739297918

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Re: Low-pass filter for audio out

Post by Helder » Sun May 15, 2016 8:51 am

So what schematic did you use to make that breadboard amp?
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Re: Low-pass filter for audio out

Post by crispy_tofu » Sun May 15, 2016 7:48 pm


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Re: Low-pass filter for audio out

Post by 1461748123 » Mon May 16, 2016 12:10 am

I got the final working version of the filter:

Image
As you can see it's now much smaller and can fit right beside the speaker :D

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Re: Low-pass filter for audio out

Post by 1461748123 » Mon May 16, 2016 1:11 am

@Helder
Yes I'm using the schem made by adafruit.
I got a cleaner version that was made by me:
Image

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