Perhaps HEAT could be detected?

R. I. Nelson wrote:

> Tim ODriscoll wrote:
>
>> Hi Everyone,
>>
>> I'm making a little PIC-controlled floodlight interface for my house,
>> and I'd like the PIC to be able to detect if the lamp filament is
>>
>>
>> My other idea was a transistor with it's base connected via a suitably
>> sized resistor to the 240v live just before the floodlight. The
>> transistor would drive an optoisolator. I've seen something similar on
>> piclist.com describing a stalled motor detector, but I've no idea if it
>> would work with a lamp of variable wattage at 240vAC.
>>
>> Any thoughts/ideas appreciated.
>>
>> Cheers,
>>
>> Tim
>>
>>  
>>
> My memory is sketchy on this but I remember as a kid 50 some years 
> ago.  We took a neon bulb and soldered 2 pieces of bell wire. ( about 
> 18 or 20 ga.solid copper wire with low voltage insulationused on 
> battery door bell circuit.  we would take one lead and ground it and 
> the other lead we would wrap around the hot lead going to the powered 
> device.  (bulb in this case)When current would flow through the wire 
> the neon light would light no current the neon was off.  I cannot 
> remeber if we added resistors or not.
>
> All you would have to dois detect the neon light on or off.  maybe 
> watch the plasement of the coil too.
>
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