When consumer products like cars first needed complex controls systems like central locking and power windows, electronics were in their infancy. Electro-mechanical relays were large, hot, loud, expensive and unreliable. This was solved instead mostly by the use of "air logic." Compressed air (or sometimes vacuum) systems use miniature 3- and 4-way air valves to fulfil the needs of the logical components and, or, not, yes, and flip-flop as well as timers and delay mechanisms. Users turn dials or push buttons which feed data into the system via air instead of electricity, and the control system actuates power controls which cause air or electrically-driven accessory controls to function. Some even used these to control engine accessories, like air conditioning, fuel timing, and emissions controls.

While it continues to be used today, it's only for specialized industrial uses. From the 1970s onward, the now cheap and reliable integrated circuit began replacing air logic and cars were really the vanguard of the all-electronic world we live in. When I encounter an air logic system, I often imagine a long-retired engineer with a shelf of industry awards and books; the father of air logic, now forgotten due to the march of technology.

This book is about handset-sized mobile phones and similar devices. I started writing in 2013, and expect it will not apply in some details in just a few years. In 10 years I hope the world has moved on enough that it is comically out of date.

Keep yourself educated, keep up to date with trends and technology, and never be so in love with a particular solution, or way of working that you lose sight of the changing world.

Air logic (last edited 2013-11-17 15:49:40 by shoobe01)