David Bray 1-Wire Barometer

This article describes details for constructing a 1-Wire Barometer which will work on a Dallas Semiconductor Corporation 1-Wire network. This design differs from the popular Version 1.1a in that it has more than twice the resolution. – David W. Bray

1-Wire Barometer – 5/10 Volt Design

“The circuit requires an additional power source other than that of the 1-Wire network. The MPX4115 requires about 7 ma of current. This is more than a 1-Wire network can provide without an elaborate circuit to store parasitic power from the 1-Wire network for short burst of current for pressure measurements.”

1-Wire drivers allow communication between a personal computer and Maxim’s 1-Wire or iButton products, and they are provided for download free of charge. Also bundled with the 1-Wire drivers download is the OneWireViewer demonstration application software. To get started, you will need the following:

1-Wire Barometer – 2002 Update

The idea is that the normal pressure swing in the atmosphere is very small — under 6%. However, it would nice to have reduced accuracy outside this range. This leads to the idea of using the current a/d for measuring small swings, and then the voltage a/d for large swings. This also has the advantage that we can use almost the entire range (10 bits worth) to measure the 6% swing. This gives a resolution of around 0.07mb.