Software Fundamentals, Dirt Cheap Dumb Wireless- fusw.htm

Please note that this is a "private" page
This page HAS had the July 2014 overhaul

See project's main page for further caveats, if you are not already familiar with them.

Software fundamentals

The general user of DCDW modules should not need the following information. It is provided for people wishing to know more about the fundamentals of the software, and about the nature of the radio signal passed between transmitter and receiver. See also the page on hardware fundamentals.

When writing software for DCDW, you may want to use low level procedures already developed by the DCDW team. If writing your own, here are some suggestions...

It is best to measure full cycles (from, say, positive edge, through "on" time, past negative edge, and through "off" time to next positive edge. Due to the nature of the wireless link, the ratio of "on" to "off" cannot be guaranteed. And if, for debugging or other reasons, the DCDW is connected directly (with a wire, no RF link) to the input of the monitoring computer, the duty cycle may be different than what it will be with the RF link included.

(Comment from WE Payne, around 2011, tweaked...) Interrupt driven software is pointless if you are using the OOK brand RF links, because in absence of a TX signal the RX chases its detector right down into the thermal noise and the data out pin dithers randomly. Main Loop() ends up going off every time to countFrequency(), might as well code it that way instead of wasting an interrupt. Also we can now (10Jan11) use any Arduino data pin.

Here is how you can contact this page's author, Tom Boyd.