NEW SOLAR POWERED LIGHT SWITCH DESIGN
How I addressed my solar light switch issue.
I have a ceiling lamp above a stair way landing that also has a sky light. The stairway has no windows, so at night it would be very dark. We like to keep a low power light on at night. The circuit has a wall switch at the bottom of the stairs and again at the top. I had installed an automatic light sensor in the skylight area to turn the light off during daylight hours. I recently installed an X10 WS4777 to replace both light switches. I modified the WS4777 adding a white wire connected to neutral.
The light sensor had been installed between the wall switch and the light fixture. I purchased a 9 watt dimmable LED bulb at Home Depot for just under $10 and installed it in the fixture.
The light sensor did not like working with the X10 wall switch. During the day, the light sensor would turn the light off which would cause the X10 module to stop conducting (the triac would not stay on). This would cause the light sensor to turn on again. The result was, the light would cycle on and off every few seconds.
My solution:
I have designed a solar powered light switch to replace the existing solar sensor. My design uses a 6 volt photovoltaic solar panel which is only 2.2" x 2.2" and will attach to a single gang switch cover. Inside the single gang box is the new circuit. I used a 1.5 farad super cap that is charged during the daylight by the solar panel CMOS logic drives a MOS FET connected across a bridge rectifier to switch the light on. The capacitor discharge current should be less than 1ua. At that rate, the super cap should be able to keep the FET on for a week.
I have ordered the solar panel and super cap. I will report on the project again in about a week.
Light Sensor Project Update
The 6V Solar Panel that I ordered was not available, so I have made a few changes to the design to work with a 5V Solar Panel.
I replaced the MOSFET with a logic level MOSFET that will work with the lower voltage.
This design will fit inside a PACTEC CNM-0000 plastic enclosure. (see attached)
I have also added an alternate design that uses a photo resistive sensor and requires a 3 wire connection.
Both designs should be fully compatible with X10 dimmers.
I have laid out a printed circuit board using ExpressPCB software and ordered 3 boards.
Each board will have 2 each of the above mentioned designs for a total of 6 each boards on my order.
The boards will not arrive until 11/28/11.
I'm attaching a schematic of each design and will send a copy of the ExpressPCB files to anyone that provides an email address (send me a PM)
However you may wish to wait for my final progress report on the project. At $65 per order, I don't plan on ordering more boards at this time.
I need to pull the schematics due to some design problems but I will re-post them once the problems are resolved.