Daylight Detector

A Daylight Sensor is a block for use with redstone circuitry, added in the Redstone Update. It works like a solar panel, emitting a redstone signal if it is bright enough (sunlight level) to do so. The strength of the redstone signal varies by the time of day. For example, the sensor will emit redstone for 15 blocks at midday but roughly 5 blocks at evening. The daylight detector emits a redstone current to any/all blocks placed directly (within 1 block) above/below/next to it.

If the Daylight Sensor has an opaque block above it, then it will emit a weaker signal, or none at all, as it is directly proportional to the sky light, which can be useful for controlling light levels with redstone lamps and pistons to cover and uncover the sensor. Using a NOT gate (also known as an inverted Redstone signal) can reverse the sensor's signal, creating a "night sensor." This can, for example, allow redstone lamps to come on at night and off during daytime.

As a night time detector
By connecting the sensor to a NOT Gate(inverter), it will output a signal when the light level is LESS than 4, so you can for example make lights that turn on at night, or gates that automatically close. Also, if you connect the sensor to a torch it works great!

As Decoration
Because energy is not something currently measured in Minecraft, you can use the sensor for decoration.

As a clock
Because you can measure exactly what light level it is, you can make a clock. For example, for every light level it is, 1 light goes on a board. When it is night, the word "Night" is illuminated on the board displaying light level or time. This can be useful for servers, especially if you do not have the ability to create one using piston memory, or do not wish for one as complicated or laggy.

As a bomb
The daylight sensor can be placed atop TNT unlike most redstone devices. If planted at about midnight, this can make for an excellent timebomb, as the TNT will be ignited when the sun rises. Since the skylight is measured, which is shadowed out by blocks above, the sensor on TNT can be used in traps for players breaking the (e.g. ore or cake) blocks above the sensor.

Timed jingle
Using some note blocks and redstone circuitry, you could make a set jingle that plays at certain times of the day, such as a device that warns you that nighttime is over, or is beginning. This could be used as a sort of morning alarm if you do not use a bed, and instead design redstone in a laboratory all night or construct underground buildings. Or this could just be a pleasant thing to get out of bed to.

As a signal
The daylight sensor can easily be used to signal things at different times of day. With command blocks in the game, it can do many more things, like broadcast messages or change everyone's gamemodes (For whatever reason). Below are different methods for it.

Mining signal
If you are mining and you want to come up at a time of day, you can connect the day light sensor and make it either send a redstone pulse down your mine or broadcast a command block message.

Command block command for message:

NOTE: On servers this will broadcast a message to the entire server. So use this command:

Message
You can send out a message to the entire server at a certain point of day. The command block command for this is: First broadcasts a message to the server, second one tells a message to a player.

Output
These tables link output values to the time they occur as well as co-occurring light levels. Note that while the sensor responds to changes in light level, the light level only modulates a separate scale that more or less follows sunlight. This modulation does make the tables invalid if the sensor doesn't have a direct view of the sky.

Night
Due to a bug, a covered sensor currently emits a signal at night. The following table corresponds to a sensor that cannot receive any daylight. Weather is irrelevant at night.

Trivia

 * Daylight Sensors only work by sunlight and cannot be activated by other light sources such as luminescent blocks or torches.
 * Daylight Sensors are less than a slab tall, which is like redstone repeaters, redstone comparators and trapdoors.
 * A daylight sensor connected to a powered dispenser via redstone wire will cause the dispenser to fire every time the light level changes.
 * Rain will affect the sensor.
 * Daylight Sensors, as well as most redstone technology, appear more similar to modern technology compared to most other blocks.
 * Daylight Sensors can be used as fuel in furnaces.
 * Due to the fact that a covered sensor gives output at night, it is possible to create a 24H Redstone clock that is synchronous with the Day-night cycle, that still works during the night.

Gallery
 File:DaylightDoors.png|Iron doors opening during daytime and shut during the night because of the daylight sensors. File:daylightsensorscomparison.png|A comparison of sensor outputs, depending on conditions. File:Automatic_Lighting.png|An example of using the daylight sensor to provide lighting at night. File:13w01a mojang release.png|The 13w01a Snapshot image. File:Sensordec.png| A picture of how the sensor can be used as decoration. File:DaylightMeterFront.png|Using a sensor and an analog-to-digital converter to make a meter. File:DaylightMeterBack.png|The sensor and analog-to-digital converter making the meter.

Tageslichtdetektor Daylight Sensor/es Détecteur de lumière du jour Detektor światła dziennego Датчик дневного света 阳光传感器