Light stat

[ehanes7612]

Anyone know if they make light sensors that switch appliances on/off when light levels go below/ above a certain point?(like a thermostat) looking to have supplemental light in greenhouse but would like lights to switch on if light falls below certain level.

 

[gonewild]

yes they make controllers that do that.

 

[Shiva]

There's one on a pole right across the road from my house.

 

[Paphman910]

You mean a photocell?

Paphman910

 

[gonewild]

I assume the question is not about a simple photocell that switches at dark or light. Maybe an adjustable sensor that will detect a preset light level and turn on the extra light.

 

[Ernie]

Thinking simple, they make these for outdoor Christmas lights so they come on automatically when the sun sets. They're usually a ground stake with a photocell on top, a female outlet, and a cord with male bits that plugs into an outlet. You can't adjust the setpoint though (unless you are some guru I guess).

 

[SlipperFan]

I have a CATMP-DNE controller for my heater. It works from a photo cell and has day and night settings. The problem with a photo cell it that it will turn on an appliance when the light level is low, but then how do you turn it off since you don't want the lights on all night?

But I think you need something more like a timer. When I grew under lights, I had a timer set to come on at a certain time in the a.m. and off at a later time. There are more complex models that allow on/off settings twice a day.

 

[Ernie]

Yeah, we used timers too. Simple, cheap, effective.

 

[ehanes7612]

I assume the question is not about a simple photocell that switches at dark or light. Maybe an adjustable sensor that will detect a preset light level and turn on the extra light.

EXACTLY!!!!

 

[gonewild]

This should work........

http://www.greenhousemegastore.com/product/igrow-solar-light-sensor/control-systems

 

[ehanes7612]

I have a CATMP-DNE controller for my heater. It works from a photo cell and has day and night settings. The problem with a photo cell it that it will turn on an appliance when the light level is low, but then how do you turn it off since you don't want the lights on all night?

But I think you need something more like a timer. When I grew under lights, I had a timer set to come on at a certain time in the a.m. and off at a later time. There are more complex models that allow on/off settings twice a day.

no, i have these...need something that will automatically turn on when light levels go below a certain point ..i live in seattle and the winter days are short and cloudy..and the sun skims the horizon (which is fine when its sunny but thats rare)

 

[ehanes7612]

This should work........

http://www.greenhousemegastore.com/product/igrow-solar-light-sensor/control-systems

thanks :clap:

 

[gonewild]

This one is better....

http://www.greenhousemegastore.com/product/shade-stat-control-system/control-systems

 

[Lanmark]

no, i have these...need something that will automatically turn on when light levels go below a certain point ..i live in seattle and the winter days are short and cloudy..and the sun skims the horizon (which is fine when its sunny but thats rare)

Combining a photocell with a timer would solve the problem of lights staying on all night as Dot had mentioned. Power the photocell controller only during daytime hours. :wink:

 

[Ray]

How about - in order in the circuit:

1) Simple timer that allows power to the rest of the circuit only as selected times.

2) Simple photocell that controls the current. Most inexpensive day/night ones are not simple on/off devices, but one in which the resistance increases with light level (which is why they work with incandescent bulbs but not CFLs).

3) A variable resistor to "tune" the current

4) A relay to switch on the full power supply to the lights when the combination of the three above allows it.

 

[ehanes7612]

How about - in order in the circuit:

1) Simple timer that allows power to the rest of the circuit only as selected times.

2) Simple photocell that controls the current. Most inexpensive day/night ones are not simple on/off devices, but one in which the resistance increases with light level (which is why they work with incandescent bulbs but not CFLs).

3) A variable resistor to "tune" the current

4) A relay to switch on the full power supply to the lights when the combination of the three above allows it.

this is what i am thinking because controllers are way to expensive...thanks!!!