Red-Dot is a 100% free, hardware-less 3D printing time-lapse software that utilises the camera to detect when to take the picture to make those awesome "growing" time-lapses

• Find something small that you can attach to the bed that is a different colour, I used a red label and cut a circle out of it
• Stick it to the bed
• Align the bed when you want to take the picture during the time-lapse, I used Y:235
• Launch the software and use the X and Y fields to align the circle over the dot
• Click sample colour and save the settings
• In your slicer, turn on the time-lapse mode (in Cura its under Post Procesing Plugins)
• Launch the red-dot timelapse and start the print