On the current "This Old House" on PBS  TV, they had a CF that they said 
was dimable.

Along the lines of this thread, I have in the distant list of things to 
do: Load management to minimize the electrical demand. Without running 
extra wire, I'd like to be able to detect when a load (sump pump, 
freezer, furnace, etc.) is calling for power. I Have a panel next to the 
main breaker panel, could run wires to that panel and then to the load. 
A PIC or PLC could then open or close the circuit, to minimize the 
amperage at the main.

Jesse Lackey wrote:
> On a related note ... I'm curious if anyone has any ideas on how to 
> detect an incandescent vs. CF (or LED) bulbs.  The relevant difference 
> being that most CF (no idea about LED) can't be dimmed.  Really not sure 
> how this could be done!  Anybody ever do this?  Can it be done reliably 
> with CF bulbs from different manufacturers?
>
> J
>
> John Walker wrote:
>   
>> Hi all! Long time lurker, first time poster.
>>
>> I am working on a project where I want to use a PIC pin to detect that 
>> an incandescent light bulb (120VAC 25W) has been inserted into a 
>> standard light socket. I want to do this by using the fact that when a 
>> bulb is in the socket its filament will act as a sort of switch across 
>> the socket contacts. There are two ways I can think of doing this:
>>
>> 1) I could use a DPDT relay connected across the socket and energize the 
>> relay when I scan the socket. (Seems dangerous to me)
>>
>> 2) I could use the technique discussed in the Microchip App. note 
>> concerning AC interfacing. The problem with this is that I want to be 
>> able to detect the bulb without having to turn it on. I could flow low 
>> current through it but that would change the component values and cause 
>> problems when the bulb is actually turned on with full current.
>>
>> I'm sure there are several other ways to accomplish this and could use 
>> your recommendations. To recap, I want to detect when a bulb is in a 
>> socket using the filament as a switch. I will use a PIC pin to monitor 
>> this and will use another PIC pin to turn the light on/off. The light 
>> will be an incandescent type operating at 120VAC and be rated at 25W.
>>
>> Thanks in advance.
>>
>>
>>     
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