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What is it? A free PIC based altimeter and vario with datalogging (barograph) and speed to fly functionality. I designed it primarily for use in hang gliding but the design could be modifed to suit other pursuits. It is relatively low cost (even cheaper if you have no display and just use it to log a flight) and has evolved to a simple hardware design. Why? Although there continues to be many excellent free flying instruments around there were none that met my requirements. I was also interested in constructing my own alti-vario to discover their limitations and investigate more about the physics of flight and weather. My requirements developed into the following: Log more than just altitude; ie. vario, speed and temperature. Have a high rate of logging so could obtain polar curve and compare glider and pilot combinations Examine temperature profile on cross country and stable days Implement some form of speed to fly to maximise cross country potential Operate without use of GPS, though be capable of interfacing to one Tetris on board! Be reasonably kind to batteries It is also worth noting that when I started GPS' were not too common, and more expensive than they are now. Latest news 22nd April 2004: This weekend will see the start of the final stage of basic testing. Once complete I'll drop in a sensor and tube for airspeed (the software is all in place) and verify the ASI aspect. Check back for regular updates! About myself I started hang gliding in 1993, qualifying in Easter 1994. Since then the majority of my flying has been with the Suffolk Coastal Floaters Hang Gliding club. Despite it's name the majority of the group spend most of their time winch launching at Mendlesham, just north of Ipswich, to heights of 1000' and more before setting off "cross-country" across East Anglia. I graduated in Electrical and Electronics engineering at Loughborough Univeristy in 1997 and currently work in the mobile phone industry. These days I'm more on the software side but handy to be bi-disciplined! Hope you find the contents of this site useful. Everything is freely usable and distributable (as a complete package) provided it's not for commercial gain. If it is then please get in touch ;) Richard Hunt March 2004 Back to top ...