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Archive | May, 2013

Software Spectrum Analyzer Using a JeeNode

nRfMon_v0_6

JeeNode user dzach put together an impressive software spectrum analyzer using the transceiver on the JeeNode:

Based on an idea that initiated in the JeeLab forums, a sample sketch and JeeLib, it provides a basic spectrum analyzer with a waterfall display along with normal frequency and time domain displays of the signals, as they are heard by the very same RFM12B module employed in the board.

Read more and get the code at the Jee Labs wiki.

Talking to the Raspberry Pi’s Serial Console with a Modern Device BUB

bubpi1

A question popped up on the Raspberry Pi forum a little while back asking whether the BUB could be used to connect to the serial port on the Raspberry Pi’s GPIO header. The answer is yes; it works quite well! The BUB is essentially a breakout board for FTDI’s FT232 chip that translates between a USB connection and a TTL-style UART. This is the chip that was on the pre-Uno Arduino (USB translation is handled in software on a second microcontroller on the Arduino Uno). The BUB (and BUB II) are used to communicate with most Modern Device and Jee Lab controllers, except for the BBLeo.

The BUB has a few other features that make it a bit more flexible than Just Another Breakout Board. For example there’s a polyfuse to help protect your computer if you accidentally draw too much current, and a jumper to change logic levels from 3.3 to 5 volts. The BUB I also has a handy breakout area that allows you to reroute the signals to any of the pins on the header. This is useful for connecting to devices with different pinouts like the Raspberry Pi or Parallax Propeller.

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New JeeLabs Blog Series: What If?

JCs-Grid-page-71-604x273

Well, it’s a relatively new series from our friends in the Netherlands that takes a more conjectural approach to learning about electronics. In Jean Claude’s words:

The what-if question is a great way to experiment, especially in electronics and electro-mechanics, because it lets you be prepared and avoid silly (and sometimes catastrophic) outcomes, such as a damaged component, a harmful burn, or even an explosion.

This approach lends itself to all sorts of practical questions:

  • What if I short out a 3x AA battery pack?
  • What if I connect my chip the wrong way around?
  • What if I have to use a 12V power supply instead of 5V?

But also issues as varied as:

  • What if I omit a certain component from my circuit?
  • What if I unplug the Raspberry Pi without shutting it down?
  • What if I wanted to use HouseMon in combination with MySQL?

Power considerations are often the most vexing part of working with electronics, and sure enough that’s where the series starts. The first few posts explore the questions “What if I mix 3.3V and 5V?” (Parts one, two, and three) and What if the supply (to an Atmega) is under 3.3V?“.

It’s a weekly series, so bookmark it, follow the RSS feed, or catch up on the wiki.