Podcasting Tools

Here are a few little schematics and stuff I have collected. I will be adding more as we go along. Each of these projects are under ten dollars each.

An old computer (that has a soundcard with a microphone input) to use with a free program called Audacity (for an internet radio station you could use shoutcast and icecast also) installed. Yes, we acquired an old computer from a local user group for free. People (obviously Microsoft users) thought It was worthless. Linux makes computer equipment more valuable.

$ sudo apt-get install audacity pavucontrol

Simple Microphone.

Microphone: (Any good piezo buzzer should work.)

We tried several piezo buzzers and found the larger ones work better. I also plan to try some old speakers also. The real tiny piezo buzzers from old motherboards need a preamp (they are not loud enough and need additional electronics to help them work better). One interesting thing is that you can also use the piezo mikes as speakers in a pinch. I was able to use the piezo buzzer as a mike from https://www.instructables.com/id/Yet-another-amplified-acoustical-guitar/ without any preamp into my sound card. It needs a preamp. In fact, all I did was sing (if you want to call it that?) into the guitar.

Note: a lot of the dollar stores will sell a microphone for at or under a dollar. But if you do not have access to one this is an alternative.

Downloads

test.wav

git.wav

Simple Amplifier 1

Simple preamp for an electret microphone that you might find in some phones. Requires 3 - 9+ volts external battery or you probably could adapt a walwart.

Simple Amp 2

Requires a bit fancier darlington transistor. (mpsw45a = nte48)

Simple Amplifier 3

Another preamp thanks to Tom Engdahl.
(bc547b = nte123ap)

Simple Amplifier 4

If all goes as planned, Plan to use all 741 circuits to be consistent. Here is the last one.

Simple Amplifier 5

Yet another 741 audio amp.

Also pictured is the pinout for the lm386

Simple Mixer 1

Untested mixer: (Hook up several mikes to one input on computer.) (741 aka NTE 941m) Why do you need a mixer? You can use several microphones or sound sources with just one sound input on a sound card. Of course, most sound cards have at least two inputs (aka stereo),

Simple Mixer 2

Another simple mixer thanks to Tom Engdahl (http://www.tkk.fi/Misc/Electronics/circuits/linemixer.html)

Putting It Together.

So far I have shown you five amps and two mixers. Now it is time to put it all together. We will be using 741 opamp (lm741 aka nte941) circuits for both the amps and the mix to make the project simple if all goes according to plans.

Under construction.

mike > preamp >
mike > preamp > mixer > soundcard.
mike > preamp >

For purposes of this demonstration we will only be using two amps and one mixer. (I know nothing about electronics.)

Using Audacity

Audacity is a great "free as in speech" program for recording input from your sound card. You can almost be like a real recording studio,
You can get Audacity from: http://audacity.sourceforge.net/ for the most popular platforms. On Linux it is usually in the distributions set of downloadable software. (i.e. sudo apt-get install audacity or sudo yum install audacity).

www.archive.org has let some people host (i.e. allow everyone on the internet to access the podcasts) their podcasts on their site. See the site for more details.

Computer Controlled Input Switcher.

If you have a podcast it would be nice to be able to add or remove inputs. Can be very easy to do with the computer. remotely. The Rpi or an ethernet enabled arduino would be good for this. You will need cmos 4066 chips and 5 stereo input jacks to complete the hardware. More details later.

Downloads

switherinio.txt