Sunday, November 14, 2010

How to use electret microphones?

Electret microphones have built-in amplifier transistors. So to get it's output you will need a pull-up resitor:

You should pay attention to which pin is connected to the case, because this is the negative pin:

Tuesday, November 2, 2010

I lost connection to my XBee module, what now?

When you program your XBee with different profiles such as API (instead of AT), your XBee will lose the ability to communicate via UART. Those modes are meant to be used with a RS232 dev board.

To get back in touch with your module you'll have to follow these steps:

1. Take the module out of the interface board.
2. Connect the interface board to the computer.
3. Open X-CTU
4. Go to "Modem Configuration"
5. Put a check in the "Always update firmware" box
6. Select proper modem from drop down menu,
7. Select proper function set and firmware version
from drop down menus.
8. Click on the "Write" button. After a few seconds of
trying to read the modem, you will get an Info box
that says Action Needed. At this point, CAREFULLY
insert the module into the interface board.
9. You may get the info box again a short while after,
just use the reset button on the interface board.

Monday, November 1, 2010

DSO Nano v2 open source portable oscilloscope

My DSO Nano v2 just arrived and guess what: It not only works as an oscilloscope but is also a development platform for the 32-bit ARM Cortex MCU!

I can reprogram it into a MP4 player or whatever I want. I can also redesign the UI if I think I can do better.