“This creative idea is suitable for a stairway with 16 stairs, each stair can have a 12V LED. It has two sensors one at the start and one at the end of the stairs and when the sensor trigered at any end it starts a process of lighting each of the steps in a progressive cycle starts. When you reach the other side of the stairway and the second sensor is triggered it will start to extinguish all the lit lights in the ascending cycle.
This is a very simple and easy to build project based on the Arduino platform The board consists of an ATMEGA328 microcontroller, 16 channel MOSFETs, 2 optical retro-reflective or optical defuse sensor, 16 x 12V LEDs, LM7805 regulator, DC filter capacitors, and optional current limiting resistor on each MOSFET. The circuit requires 12V DC, each MOSFET can drive a LED up to 1A (0.5 to 12W LED)
LEDs: Each MOSFET can drive LED of 0.5W to 12W, it is advisable to use 12V LEDs, use appropriate current limiting resistors (R3, R15, R23, R31, R7, R17, R25, R33, R11, R19, R27, R35, R13, R21, R29, R37) if lower voltage LEDs is used. The default value for these resistors is 0 Ohms.
Sensor: Optical Retro-reflective sensor or optical defuse sensor can be used. The project is tested with a reflective sensor from Omron, NPN type sensor is best suitable. The optical sensor has a supply range of 12V to 24V DC which is within the supply range to interface with this project. Retroreflective sensor E3F3-R11 from Omron is suitable, it has 3 meters range with an open collector NPN type. Defuse sensor E3F3-D12 can also be used if it used in a narrow range.
Stairway: Circuit can drive 16 channels, for more steps, use multiple LEDs in parallel configuration considering load should not exceed 1A on each channel.
Cooling: It is advisable to use forced air to cool down the MOSFETs if full load 1A on each channel is used, load up to 0.5A on each channel doesn’t require a fan.”