Hi there! I am working on an application that uses HMC1001 (single axis magnetic sensor) to measure the value of the magnetic field around a current carrying conductor. The output is obtained as small voltage which can be measured by the ADC of telosb. Though the datasheet of HMC1001 specifies an op-amp circuit to amplify this voltage, the ADC is able to read small values as well. I've simulated roughly, the output using a signal generator which gives a sinusoidal output at about 50Hz with a 10mVpp amplitude. However, the ADC on telosb in unable to read the negative values and displays a zero value for all the readings in the negative half cycle. I wish to introduce a DC offset to this output using the DAC to generate a constant voltage of about 1V. How can this be done? I'm unable to find any documentation and interfaces related to the DAC on telosb. Also, the sensor requires about 5V at 10mA. I'm planning to use one of the GPIO pins to give it that supply voltage as a pin set high is expected to be at 5V and according to the datasheet it supplies about 6mA I guess. However, I'm not sure if this approach would work. What is the best way to interface HMC1001 with telosb and how do I use the DAC on telosb? Kindly clarify my doubts. Any help will be greatly appreciated.
Thanks and regards, -- T.Vignesh Final Year Thesis Student, Electrical and Electronics Engg, BITS Pilani-Goa Campus
_______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
