Posted tagged ‘electronic sensors’

PASSIVE LIGHT SENSOR

August 22, 2011

Rain sensor systems:

Opto electronic sensors are used in a reflective mode in rain sensor systems to detect the presence of water on the windshield so that the windshield wipers can be controlled automatically.

01-rain sensor-rain gauge-electro luminescent diodes-ambient light sensors-light sensor-LED-Light emitting diode

An LED emits light in such a way that when the windshield is dry almost the entire amount of light is reflected onto a light sensor. When the windshield is wet, the reflective behavior changes: the more water there is on the surface, the less light is reflected. In the new rain sensor, infrared light is used instead of conventional visible light. This means that the sensor can be mounted in the black area at the edge of the windshield and cannot be seen from outside.

Working Operation:

01-ambient light sensor-working principle-reflection of infrared light-electro luminescent diodes


An infrared beam is reflected off the outer windshield surface back to the infrared sensor array. When moisture strikes the windshield, the system detects a reflection to its infrared beam. Advanced analogue and digital signal processing determines the intensity of rain. The sensor communicates to the wiper control module, which switches on the wiper motor and controls the wipers automatically, according to the moisture intensity detected.


01-Rain sensor-auto dimming mirror-light sensor

Depending on the quantity of rain detected, the sensor controls the speed of the wiper system. In conjunction with electronically controlled wiper drive units, the wiping speed can be continuously adjusted in intermittent operation. In the event of splash water – as when overtaking a truck – the system switches immediately to the highest speed.

01-Rain sensor working principle-auto dimming mirror

The new rain sensor offers further options. For example, it can be used to close windows and sunroofs automatically if the vehicle is parked and it starts to rain. It can even be fitted with an additional light sensor to control the headlights – at night or at the entrance to a tunnel, the lights can be switched on without any intervention by the driver.

For Windshield wipers working operation Click this Link.

Light Sensors:

Automatic lighting of the headlights is controlled by a passive light sensor. It measures available light using a set of photo-electric cells.

01-light sensor-rain gauge-electro luminescent diodes-ambient light sensors-rain sensor-LED-Light emitting diode

The light sensor comprises three lenses that focus the light onto three photo-electric cells. This allowed “the luminous space” surrounding the vehicle into several zones through the directivity of each basic lens cell pair.

  • Lens 1: Measure total ambient light
  • Lens 2: Intersect Front source of light
  • Lens 3: Distinguish Road Condition (Like brighter sunny weather condition or Dark tunnel)

By comparing the information gathered by these three devices, the system computer determines the situation with which the vehicle is confronted and commands the headlights in consequence.

SMART GLASS WITH SPD TECH

August 22, 2011

Electro-chromatic mirrors system:

01-electrochromatic rearview mirrors-auto dimming mirrors

Electro chromatic mirrors / Auto dimming mirrors use a combination of opto electronic sensors and complex electronics (sensors, circuit boards, micro-controllers, etc.) that constantly monitor ambient light and the intensity of light shining directly on the mirror. As soon as sensors detect glare, the electro chromatic surface of the mirror becomes darker to protect driver’s eyes and their concentration.

01-electrochromatic exterior rear view mirrors-auto dimming side view mirrors

The electro chromatic technology usually is applied to the inside rearview mirror / Side view mirror, where it basically saves you the trouble of flipping the mirror manually if blinded by the light which increases driving safety.

Working operation of Electro chromatic mirrors:

This auto dimming rearview mirror is installed on higher end vehicles. It consists of two lenses that sandwich an electro chromic (electronic color changing) gel. The inside sides of the lenses are coated with a transparent conductive layer coating and the deepest lens has a reflective coating.

01-electrochromatic rearview glare free mirrors-automatically darken by opto electronic sensor

This gel, when charged with electricity darkens, then clear once the glare is no longer detected. The mirror uses a forward sensor which measures the outside ambient light, and a rearward sensor to look for glare. When dark enough, it sends current to the electrostatic gel, darkening it a rate which is related to the level of ambient darkness and rearward glare. When the outside ambient light increases, the current decreases, until the gel is clear again at daylight light levels.

Electro chromatic auto dimming rear view mirror