All,
I purchased some light switches that are capacitive touch and can be controlled with 433 Mhz radio codes (all sorted & working). However the communication is only one way (to the switch), which toggles on/off with the same code, leaving me no way to determine whether the light is on or off from a remote position (i.e. from another room or controlling from a server). The switch itself draws power continuously meaning there is 240v downstream of the switch at all times. When the switch is off the current is 50 mA and climbs from there when the light is turned on depending on the power requirements. In my test rig a single bulb takes it to 180 mA. However in real life it would be more.
The micro-controller I wish to use to monitor this (esp 8266) runs at 3.3 v and has plenty of free digital pins but only 1 analog pin so would not be able to monitor multiple lights independently using a non-invasive, coil type, sensor. and as there is always power I cannot use a voltage sensor.
I located this K370 Threshold Sensing Optocoupler that I think can be made to fit the bill, wired in parallel with the light downstream of the switch. If I set it up correctly I can ensure that in the "off" condition there is insufficient power to light the led of the sensor but in the "on" position there would be. this would then provide me with a clean, using a capacitor, digital signal to determine the light status for my micro-controller. The low voltage side does not really concern me much as it is similar to any optocoupler.
Unfortunately, for me, the spec sheet, though comprehensive, is of language that is "above my level of comfort". I am having problems determining the correct starting value for the resistor Rx (see Isolation....... .pdf). As I am unfamiliar to working with AC power and the concept of load effecting voltage at this level any suggestions or guidance on how to proceed, especially starting values for Capacitors (to smooth) & Resistors, would be gratefully accepted.
Craig Rosier.
I purchased some light switches that are capacitive touch and can be controlled with 433 Mhz radio codes (all sorted & working). However the communication is only one way (to the switch), which toggles on/off with the same code, leaving me no way to determine whether the light is on or off from a remote position (i.e. from another room or controlling from a server). The switch itself draws power continuously meaning there is 240v downstream of the switch at all times. When the switch is off the current is 50 mA and climbs from there when the light is turned on depending on the power requirements. In my test rig a single bulb takes it to 180 mA. However in real life it would be more.
The micro-controller I wish to use to monitor this (esp 8266) runs at 3.3 v and has plenty of free digital pins but only 1 analog pin so would not be able to monitor multiple lights independently using a non-invasive, coil type, sensor. and as there is always power I cannot use a voltage sensor.
I located this K370 Threshold Sensing Optocoupler that I think can be made to fit the bill, wired in parallel with the light downstream of the switch. If I set it up correctly I can ensure that in the "off" condition there is insufficient power to light the led of the sensor but in the "on" position there would be. this would then provide me with a clean, using a capacitor, digital signal to determine the light status for my micro-controller. The low voltage side does not really concern me much as it is similar to any optocoupler.
Unfortunately, for me, the spec sheet, though comprehensive, is of language that is "above my level of comfort". I am having problems determining the correct starting value for the resistor Rx (see Isolation....... .pdf). As I am unfamiliar to working with AC power and the concept of load effecting voltage at this level any suggestions or guidance on how to proceed, especially starting values for Capacitors (to smooth) & Resistors, would be gratefully accepted.
Craig Rosier.
