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--- bcss:page [14:44 02/05/2026] – [Notes on sensors etc.] Richard White
+++ bcss:page [14:41 06/05/2026] (current) – Richard White
@@ Line 8: / Line 8: @@
 for the meeting on Tuesday 5th May 2026
+:NOTE:
+Tom Radford showed a small battery-powered data logger
+(similar to or identical to this one:
+https://www.amazon.co.uk/Temperature-Elitech-RC-5-Calibration-Certified/dp/B075B88C5B;
+there is a more expensive orange version which might differ only in having PDF export)
+which recorded temperature readings which could be downloaded via USB.
+He said they are certified for accuracy within a part of one degree,
+and are widely used in the chilled meat industry.
+The difference between such a data-logger and my approach is that
+the latter allows for remote monitoring and for actions to be taken
+either manually or automatically in the light of the data obtained.
 <WRAP colmedium>
-=== Outline ===
+==== Outline ====
-  * Show an alcohol thermometer.  You might have one of these in your greenhouse.
+=== "Stand-alone" sensors ===
+They can tell you what's happening, if you remember to look at them.
+  * **Show an alcohol thermometer**.  You might have one of these in your greenhouse.
     * More sophisticated ones can be digital (show one of mine)
     * You need to go into the greenhouse to read it.
     * It's no use if you are at work or away on holiday.
+      * A max-min facility can be useful if you can look at it at some time every day (the digital one here shows the minimum and maximum temperature and humidity for the last 24 hours, which removes the need to keep resetting it).
     * Or you might look at the weather forecast and hope it's correct.
+=== Remotely readable sensors ===
+So you don't have to go out to your greenhouse in the pouring rain.
   * Some sensors can be read remotely
     * Oregon Scientific uses radio waves (like Wi-Fi but using a proprietary protocol) to communicate with remote temperature sensors.  Show mine (if I can get it to work reliably).  This is what got me interested in the possibilities for remote sensing.  I had two or three remote sensors in my greenhouse (actually a conservatory) for many years.
+  * As well as sensors, some devices can be controlled remotely.
+=== Remotely controlled devices ===
+  * TVs have contributed to national obesity levels by the invention of the remote control, saving you the effort of levering yourself up from the sofa.
+  * This where I got interested in remote controls - my mother's light switches.
+  * **Switch the light on and off** using the IKEA Rodret push-button switch.
+=== Multiple sensors controlled from a base unit ===
   * Some companies started to develop their own "smart home" systems, using their own different proprietary protocols, but these would lock you into using only their products (just like Apple does).
+  * Some more recent devices from some companies **appear to lock you in**, but in practice they don't.
+  *
   * Recently, more open public-domain standards have been introduced, so that devices from different manufacturers can be more interoperable.  These standards include Zigbee and Z-Wave (using the same radio frequencies that Wi-Fi uses, which don't need a licence for low-power use) and i2C (for daisy-chaining devices together by wire).
   * These standards mean that you don't have to become wedded to a single manufacturer and not be able to mix and match.
@@ Line 73: / Line 107: @@
   * Thermometer (alcohol) from hall
-  * Thermometer (digital, unconnected) from lounge
+  * Thermometer (digital, max-min, with humidity, unconnected) from lounge
   * Ohio Scientific display unit and remote sensor
   * Large laptop (Crocus) with Samsung monitor
+  * Zigbee sensors:
 </WRAP>