In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:

I see Bean's log table used merely 10 lines of 3 items each [Appears to be Value, Log, Antilog]

The TAOS sensor has a fairly convoluted method of outputing its readings to cover a complete range of intensity, so the range is a bit difficult to explain.  I will have to re-read the material in order to get a good idea of what resolution.  Just from memory, I think the raw reading are up to 10,000.  But I may be wrong, so I'll post real fact tomorrow.

I guess I should take a log at an old fashioned natural log table to get an idea of what range and level of detail.

Expansion requires division.  Both the multiplication and division processes are quite demanding of an RISC microcontroller; so converting to logs and doing subtraction or addition and converting back seems more appropriate to me.  Either you can use a chunk of EEPROM or your code can hang up in iterations for awhile.

Simply put, the TAOS sensor is quite good quality - but very technically exotic and challenging.  
I am interested in it for measuring ambient light in orchid production.  Apparently, what is currently being used is not  reliable because single photodiodes can be swamped by IR from electrical lighting or heating; and have problems with 50 or 60 cycle hum.  This particular sensor claims it does not, so it would allow them to agument heat and agument light with grow lights in a predictable way.

TAOS was kind enough to send me 5 samples, but even the serial interface requires a custom approach.

As it stands, they have their whole automated light control shut down.  I believe they are using a photo light meter for spot checks and watching the orchid leaves for appropriate intensity of green.  Certainly job security for the greenhouse crew, but the owner would love to at least remotely monitor and confirm they are making optimal evaluations.

---------- End of Message ----------


You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162343#m162379

Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com

The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)