LDR - seems to be useless even I calibrated it by uncommenting the section.

[AndreiBurdea]

Also - can you modify the code for use with two ultrasonic sensors instead of pir ? That can be fine tuned and oriented more precise to detect the persons. Good job, congratulations !

[Vinz68]

Hi, I understand that you could not manage to get the LDR working ? How can I help ?

You say you uncommented the section ; but there is one setting to use (or not use) the LDR as documented: bool useLDR = true; // flag, when true the program uses the LDR, set to "false" if you don't have a LDR sensor.

Note: that depending the LDR you are using ; and its resistance (ohm) changes , the analog value read from it might be different. That is why it is important to use the serial monitor; where you can see the value which was read. By changing the light on the sensor you could determine on which value it is dark enough to enable the lights. This value is also a setting (configurable): long LDRThreshold = 600; // Only switch on LED's at night when LDR senses low light conditions => you may have to change this value for your circumstances!

Good luck; I hope that this info helps you ? Plz let me know if you need further help.

[AndreiBurdea]

Hi! Thanks for reply. I set the value of useLDR=true I uncommented the section for serial print the value of sensor. I covered the sensor to obtain a reference value dor dark. Then I uncovered the LDR to get a value for light. I set the threshold between that 2 values for testing. Then the stairs run continuosly with or without simulated daylight, even when is no move in front of PIRs. Just turning on and off the stairs. When I set the useLDR to false... all is running normally. I connected the GND of atmega2560 to GND of led strips. I powered the Atmega2560 with a PSU (5v 1A) and the led strips with 5v 72A (I use 18 led strips with 144 leds each). And a second question please: how can i change the breating leds color ?

[Vinz68]

Hi Andrei, starting with your last question about the breathing leds color:

• you need to modify the handleBreathe function , which starts on line 263
• setting the breathe leds on a certain color is done in two steps 1) first the left-hand led(s) on the stair-strip are turned on and the color is set on line 294 with: strip.setPixelColor(i, strip.Color(0,0,breathe)); where the 3 arguments of the strip.Color are the RGB values of the final led color. 2) then the right-hand led(s) on the stair-strip are turend on (line 302); with currently the same RGB values. Current function just changes the third argument => which is the Blue part.

About the first part; it is good to monitor the LDR values during normal operation in the serial output window during your test when lights stayed on.

• like you did ; determine the value for " light" , "dark" and at which value it is dark enough to turn the stairs on (configure this last value as LDRThreshold. Which 3 values did you determine ? Having your " values" might help me to solve your problem.
• when the LDR value is below the configured LDRThreshold then detection on one of the PIR sensors would enable your stair light.
• note that there is some smoothing/averaging on the LDR value (so when someone would walk by, its shade would not trigger/enable the LDR). When it slowly get darker over time and LDRValue reaches a value below the threshold then the logic should do its work and enables the PIR sensors.

[AndreiBurdea]

Thank you for clarification. I will try to have patience between each setting on LDR. What kind of arduino do I need for a 18 stairs x 144 leds (each) ? I see on internet discussions that one pixel needs 3 bytes of sram...

[AndreiBurdea]

Hi again ! Can you help me to change the color of the stair leds ? (when all turned on) Thank you !

[Vinz68]

Hi, you need to change line 195: strip.Color(255, 255, 250) . Which determines the RGB colour.