Friday, January 21, 2011

Building a Handheld Digital Compass

I have decided to build a handheld digital compass for orienteering, with altitude and temperature functions. I haven't used a compass in decades, and some folks have never used one, so I thought I'd post a link to a great tutorial describing the parts of a compass, and how it's used. Enjoy!

Thursday, January 20, 2011

Compass module with altitude

One of the goodies I received from Hacktronics the other day is the HDPM01 module. The HDPM01 module includes a pressure module and a compass module. Apparently, there is also a barometer and a temperature sensor on this module.

The HDPM01 pressure module includes a piezo-resistive pressure sensor and an ADC interface. It provides 16 bit word data for pressure and temperature related voltage. With the help of a highly accurate calibration of the sensor, 11 unique coefficients were stored on the chip, thus accurate pressure and temperature reading can be realized. HM03 is a low power, low voltage device with automatic power down switching. I2C Serial Interface is used for communications with a microprocessor. Sensor packaging options are SMD (with metal cap)

The HDPM01 is a dual-axis magnetic sensor, it is a complete sensing system with on-chip signal processing and integrated I2C bus, allowing the device to be connected directly to a microprocessor eliminating the need for A/D converters or timing resources. It can measure magnetic field with a full range of ±2 gausses and a sensitivity of 512counts/gauss @3.0 V at 25°C.

Wednesday, January 19, 2011

Virtual Breadboard - Simulate an Arduino

Want to try out your designs virtually, before committing to hardware? You can sim the Arduino, and many other microcontroller platforms at

See the video at

A Helping Hand

This past weekend I picked up a very handy gadget, a Helping Hand. Two adjustable alligator claws to hold circuit boards or small work pieces, a holder for my soldering iron, and a LED lighted magnifier make my Arduino experimentations a lot easier. $10 at "Workshop Tools".

Tuesday, January 18, 2011

Hacktronics Goody Package Arrived

A box arrived from Hacktronics today. Inside was 4 1w RGB LED's, 3 LM317 voltage regulators, 10a Power MOSFETS, 7 npn transistors, resistors, a compass module, 5 potentiometers, and a 12vdc 1a ac adaptor. Over the next few days I'll be posting pics, videos and code.

Monday, January 17, 2011

RGB LED Mood Lighting

While I'm awaiting the delivery of my 1w RGB LED's and the MOSFETS to drive them, I thought I'd share some examples of projects built by Miguel Sánchez that I'm a big fan of.