An ambient light sensor in an LCD monitor or display system can be used to enable automatic backlight adjustment or power standby. It can be used to dim the backlight to match current lighting conditions or power off the whole display. It is also possible to add a delay so that the automatic adjustment only takes effect if there is a persistent change to the ambient lighting. So for example auto adjusting the backlight in a monitor in the wheelhouse of a boat or an outdoor public digital sign as these will be required to operate in both bright daytime conditions as well as at night. For a digital whiteboard the configuration may be when people leave a room and turn off the lights, the display powers off to standby and then powers on again when lights are turned on.
Digital View Implementation
Digital View has three implementations for working with ambient light sensors.
- The Autobrite add-on board as an interface to enable automatic backlight adjustment.
- 2 pin ambient light sensor add-on board or cable mounted sensor.
- 3 pin ambient light sensor add-on board.
Details of these are available on the Ambient Light Sensor webpage, in addition this Summary (PDF download) shows compatible models.
When designing a monitor a light sensor can be placed in a suitable location to detect changes in lighting and adjust the LCD panel backlight brightness appropriately. In addition we can enable a custom firmware modification to add a delay, that way the backlight brightness only adjusts if there is a persistent change to the ambient light.
Using an updated version of the TCP-IP Serial Utility that will be released late November 2019 it will be possible to set thresholds for ambient light and the LCD panel backlight adjustment.
SVX-4096 & SVX-4096-120
The attached app note (see download link below) applies to Digital View SVX-4096 and SVX-4096-120 LCD controller boards, it shows the connection of a light sensor and the setup of the levels. Note: When choosing a light sensor, use a 2 pin type. The levels can be adjusted as described in the application note to suit the particular model chosen.
Download the appnote here:
2 Wire Supported Models
Models supporting the 2 pin light sensor:
> SP-1920 (P/N 417600021-3 or up) starts from V1.16.00.00 firmware
> SP-1920-DUAL-HDMI (P/N 417760010-3) starts from V1.18.00.00 firmware
> ALT-1920 (P/N 417640020-3) starts from V1.02.00 firmware
> DT-1920-HDMI (P/N 417700001-3) starts from V1.01.00 firmware
> DT-1920-VGA (P/N 417750000-3) starts from V1.00.00 firmware
> DT-1920-DP (P/N 417740010-3) starts from V1.00.00 firmware
For users wanting to add automatic light sensor backlight adjustment support to other Digital View LCD controller boards, we also have the Autobrite board.