Human eye contains optical lens too. With its help the image of the perceived world is created on the retina: all the light rays arriving from a single point in the space (for instance a point on the computer screen) meet in a single point at retina. Retina is full of "optical sensors" (rods and cones). Collected and preprocessed information are sent further using optical nerves to the brain. At the place where the optical nerve is connected to the eye, the retina is interrupted - it contains no sensors and the eye is unable to the arriving light at this place: we tolk about the blind spot.

Cover your left eye, move your face to a distance of about 20 cm in front of the display and focus your right eye on the cross in the picture below. Slowly move your head in a forward-backward direction until the black point on the picture disappears. Then you will have found your blind spot.

source: snowbrains.com

Task: Build a robotic equipment device into which a human places its chin or fixes his or her face in some other way. With the help of the reactions of the human - such as pressing a touch sensor, waving hand in front of an ultrasonic sensor, etc. the device will find the center of the subject's blind spot and it will measure its size in angular degrees of the subject's field of view - both in the horizontal and vertical directions. Please include your device user manual. Test your device on multiple subjects.

Who did not experience this? Your brother found a thread or ribbon with something fastened to it - such as keys, pendant, or a ball, he took it and started to rotate with his hands. It could be a surprise, but with just a little effort, it is possible to achieve a relative high speed in tens of km per hour! :-)

Falcon 9, source: space.com

Task: Build a robot that can put something into a rotation. Robot will use some trustworthy method to measure the velocity of some point of the rotating object. The measured velocity will be shown on the display. Only the team that will reach the highest speed will get 3 points. If you cannot measure the speed, try to estimate it. Warning: make sure the furniture and all living beings in the room are not harmed in any case, please ask an adult for supervision when testing your solution.