When you are in the car and it starts to rain, windscreen wipers are automatically activated and they allow a clear view of the road. This everyday object has changed a lot since its inventor, Mary Anderson, conceived it.

The following picture shows a rain-sensing feature of a windscreen wiper:

Source: https://docplayer.es/50639862-1-limpia-lavaparabrisas.html (20/03/2022)

1-receptor diode  

2-electronic card

3-light emitting diode

4-transparent silicone gasket (optical connection sensor box/windscreen)

5-heater (de-icing and anti-mist)

6-raindrop

7-prisms (input guides)

8-exterior surface of the windscreen

Other webpages in English that the teacher can use to adapt this activity are:

https://carbiketech.com/rain-sensing-wipers/ (12/04/2022)

https://openroadautogroup.com/blog/how-rain-sensing-wipers-work (12/04/2022)

1.Describe briefly how it works.

2. Is it an open-loop or a closed-loop control system? Justify your answer.