One would be to get a light source and photocell.

Photocells were used to turn on and off the sound sources.

The light is changed to electrical current by the photocell.

Besides, she had the photocells to top it up with.

Most modern units have a photocell so that they only turn on when it is dark.

"The photocells are back on," he said in a dry voice.

While he admired himself, a photocell could trip the camera.

In addition, the operation of the light is controlled by photocell.

Data was read off the card by moving it in front of a fixed photocell.

At present, much research is being carried out to improve the efficiency of photocells.

Suddenly, the head turned to her, its photocells glowing brightly.

"Reaction speed of a photocell," said the young man slowly.

The light that passes through the film shines on a photocell.

His head was molded to the human model, and he had glowing photocells for eyes.

It must be dark enough at ground level to trip the photocell that controlled the lights.

At the bottom of the figure is one enlarged photocell, a rod.

The photocells are pouring in power, a great relief after nearly freezing to death.

The photocell picked up both the direct and reflected flashes.

An example would be to turn on the parking lot lights when a photocell indicates it is dark outside.

He stuck the photocell to the screen, covering the brightness.

If someone in here wants to raise or lower the intensity of lighting, it's all photocells.

"Five hundred thousand a second is the reaction of a photocell.

The building uses photocells and motion sensors for general lighting.

Shine the light from one side of the tank to the other and record the voltage on the photocell.

Changes in environment which had a physical effect on the photocells frequently led to crosstalk between tracks.

"No photo-cell would handle all that stuff you're shooting at them.

Note that in this picture, each photo-cell yields just 0 or 1, not values in between.

A single photo-cell on the retina may be an input to several nodes.

They'll clap him into a photo-cell and keep him there until they investigate.

This feature also used a photo-cell which could fade over time, and was remedied the same way as "Repeat."

Remember that the televisor eye there is a photo-cell of the newest Dinwiddie type.

"The lens concentrates it and pours it into a receiving chamber, probably a huge photo-cell.

This feature often faded in functionality because it used a "photo-cell" which contained neon gas that could evaporate over time, but this is fixable by locating and installing an appropriate replacement component.