Archive for the ‘DIY’ Category

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Happy Holidays

In DIY,Photos,Slice of Life on December 26, 2010 by ryepdx Tagged: , ,

Hope you all had a merry Christmas yesterday! I woke up at around 11am and came downstairs to find my mom making drapes for our kitchen window. Here’s a photo of her handiwork:

Red drapes.

Apparently one of our tablecloths had gotten a little too stained and worn for use. You couldn’t tell that from seeing it hung up though. A handy idea for all you DIYers who like to use things that would normally just be discarded. (“Upcycle” is the word, I believe.)

Just thought I would share that with you all. Tune in tomorrow for the continuing adventures of a computer scientist turned creative! 🙂

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How To Make a Condenser Mic for Under $20

In DIY on December 22, 2010 by ryepdx

Alright, here’s the how-to I promised you last week. Hope it helps any of you who might be trying to make a microphone like the one I made!

List of Parts:

  1. Condenser mic cartridge (I got mine from the component bins at Radio Shack)
  2. 10.0UF/100VDC metal-poly capacitor
  3. 1000PF 100V ceramic disc-style capacitor
  4. 9V battery snaps
  5. 2.21K ohm 1/4W 1% metal film resistor
  6. Male XLR plug
  7. 9V battery holder
  8. Casing for the mic (I used a Zhena’s Gypsy Tea tin)
  9. Wires
  10. Heatshrink tubing (optional, but can help prevent shorts)

You can get all of these parts on DigiKey.

You will also need a soldering iron and some solder.

Note that though I used a Zhena’s Gypsy Tea tin for my project, you might do better to use something else. I had trouble with the tea tin altering the sound of the microphone, making it sound really cheap. I mitigated some of this by stuffing the tin full of cloth, but the best solution would have been to either allow the lid to flip up so the sound never enters the tin itself or to simply use a different case.

Here is the schematic for my project:
Schematic

Step 1:
Solder the disc capacitor between the mic cartridge leads. Be careful doing this as excessive heat can damage the cartridge.
Capacitor soldered onto cartridge.

Step 2:
Solder together pin 1 and the ground pin on the XLR plug. Solder the 10.0UF capacitor to pin 2 and, to pin 3, a wire long enough to reach from the XLR plug to the mic cartridge when you put the whole assembly in its case. Add heatshrink tubing as you go, if you’ve opted to use it.
The XLR plug soldered into place.

Step 3:
Now let’s put it all together! Solder the positive lead (in this photo, the red wire) from the 9V battery snaps to the wire coming from XLR pin 3. Solder the negative lead to the wire coming from XLR pin 2. Solder wires onto the mic cartridge if you find you need more distance between the XLR plug and the cartridge, and then solder the negative lead from the cartridge (the one with extra solder/connections running from it) to the wire coming from XLR pin 2. Solder the other lead to the wire coming from XLR pin 3.
You should end up with something like this:

You could use the microphone now, if you like. In fact, you probably should, just to make sure that you soldered everything together right before you go putting it in a case. Everything from here on out is up to you and depends entirely on the sort of case you decide to use. Here is what I did, though. Consider the remaining steps optional.

Step 4:
Carve out a few holes in your tea tin. You’ll need three on the bottom (one for the XLR plug to fit through, two for the screws to hold it in), several on the top to allow sound in, and two on the side for the screws for the battery holder. I used a box cutter and a twisting, drilling motion for this, though I would recommend a dremel or something of the sort if you have access to one. As you can see in this photo, I slipped a bit with the box-cutter while cutting out the XLR hole, which led to a bit of trouble in actual use with the action of connecting and disconnecting the mic breaking the thin bit of metal left around one of the screws.
The holes cut.

Step 5:
Pull the whole assembly through the XLR hole and fasten it to the case. I used screws scavenged from old video cards, as these came with nuts and were small enough to fit through both the XLR holes and the battery holder holes. I also used a bit of electrical tape to hold the microphone cartridge up against the lid of the tea tin.
The whole assembly in place!

Stuff the sucker with cloth to get rid of that tinny echo and you’re ready to go. Here’s what mine sounds like:

And there you have it! A detailed, step-by-step explanation of how I made my condenser mic, as promised. Hope it was somewhat illuminating. Tune in Friday for my usual fare.

Based on the instructions at www.christianmusicweb.com/microphones/mic_project.html