[colug-432] Monitoring an analog, external device's power usage?

[jep200404 at columbus.rr.com]

On Sat, 26 Jan 2013 13:53:33 -0800 (PST), Peter Kukla <fruviad at yahoo.com> wrote:

> I'm a new home owner, and I have a sump pump in the basement that I would like

> Does anyone out there have any Linux-friendly solutions for monitoring power u

You'll find plenty of sump pump monitoring projects on the web. 

> The sump pump currently plugs into a power outlet. 

AC power can go out when you need it most, 
when a big storm dumps much rain. 

3. Have a battery powered sump pump in _parallel_ with AC powered
   sump pump. Redundancy is a good thing. Big storms bring much 
   water and you can lose AC power when you need it most. 
   Set it up so that the battery powered sump turns on at a
   higher water level than the normal pump. 
   _Practice_ powering the battery powered sump from your car. 

This would be in addition to your measuring and remote alert stuff. 

By the way, the very idea of building a house to _need_ a sump 
pump is a poor one. It makes a house vulnerable to flooding. 
Well designed/built/placed houses don't need sump pumps. 
If you need a sump pump, you're in a bad place for a house. 
I'm quite aware that building codes require sump pumps. 

I was going north on 3C from SR161, and marveled at a housing 
development that was being built. There was much heavy 
equipment. The equipment was idle and there was nobody around 
because the land was underwater. A few years later, there 
were many houses. Pay attention to topography when buying 
a house. When you're in the country, notice where the _old_ 
houses are. 

Also, sump pumps die. Plan and prepare for it. A dead sump 
pump might use no power, so it's better to monitor water 
height in the sump. To go from water height to PC, I 
would probably use the line-in audio jack. The output 
_frequency_ of the audio signal would indicate the water 
height. A very crude sensor would be float on the arm of a 
variable resistor. I would likely use a non-contact sensor. 
I would either use an ultrasonic transducer to measure the 
distance to the water, or use a capacitive sensor. 
Microcenter or Radio Shack might have ultrasonic stuff in 
the northwest corner of the store past the service counter.