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Some additional Javelin demonstrations developed by students are discussed here.

Demo 2: Java Processor Student Demo: Javelin for Location Finding & Radiation Counting

Another demonstration project (ref. Garari and Mansouri), discussed in more detail in the Web Course, involved the development of a system with the Javelin Stamp to provide location measurement and sensor data recording in a small Unmanned Arial Vehicle or UAV. The goal is for the plane to fly autonomously and measure radioactivity in the air. The whole payload, including batteries weights and the UAV is less than 7 kg.

The horizontal plane position of the UAV comes from a GPS-module read via a serial line. The GPS module provides data in a standard protocol and code was written for the Javelin to translate the readings to longitude/latitude values. For the altitude coordinate the Javelin measured the analog voltage output from a pressure gauge. The Javelin library provides a virtual peripheral object for Delta Sigma 8-bit analog-to-digital conversion for voltages between 0 and 5V on any of the I/O pins using just a few passive components (two resistors and a capacitor).

For the radiation measurements, a standard Geiger counter with passive components and an operational amplifier for the output of the GM-counter. Another A/D converter converted this analog voltage to value proportional to the count rate.

Garari and Mansouri carried out bench tests of the system and found that it perform satisfactorily (ref.). Figure 23.5 shows the schematic for the Javelin connections to the Geiger counter and to the pressure gauge. The serial port connection to the GPS module is not shown. The serial connection for programming interface, however, is indicated.

Fig. Schematic showing Javelin Stamp and the connections to a pressure gauge
(for vertical coordinate), and the Geiger counter. The serial programming port is shown
but not the serial connections to the GPS module (used to find the horizontal coords.).

Documentation and Java class files are available:

• Hosseyn Karimi Garari, Daryoush Mansouri, Radiation Surveillance by Unmanned Aerial Vehicle (UAV), Diploma Work, Physics Dept., Royal Institute of Technology, 2003. (MS Word file - in Swedish)
• Class files:
  • altitude_count.java
  • BigDigit.java
  • GPS.java
  • HorizontalMovement.java
  • radio_active.java
  • SprialMovement.java
  • test.java
  • test_backup.java
  • TotalMovement.java

Demo 3: Java Processor Student Demo: Javelin for Solar & Temperature Measurements

A student project used the Javelin to carry othe measurements of a basic weather station that included a "thermometer for temperature, photoresistor for dim light intensity sensing and solar panel for daylight intensity measures. These sensors are used to register daily light changes in the amount of light and basic properties of solar cells. The solar panel is also used to measure some basic laws of light intensity."

Documentation and Java class files are available:

• A Task in Java Embedded Circuit Programming with Javelin Stamp, by Jaakko Pajunen, March 14, 2004 (pdf) - project report.
• The program is described in the report and the class files are listed here:
  • Alarm.java
  • Luminosity.java
  • PowerSource.java
  • Thermometer.java
  • WheatherStation.java

   

Most recent update: Oct. 18, 2005