From: mike on 14 Apr 2010 09:58
I want to make some short term measurements of electricity usage.
My meter puts out an infrared pulse for every watt-hour.
I just need to measure the time between pulses.
It seems like a PDA could do that quite easily if I could
figure out how to get direct access to the IR detector.
I can use PalmOS or ppc2000-wm5.
I have access to simple compilers that will let me receive
data via the IR port, but I have not figured out how to
acquire just one pulse. Probably needs to be interrupt
driven so I can do a few calculations and plot the data.
Pointers to documentation and FREE tools to do it?
I can stick an IR detector on a PIC processor and spit out
RS232 over bluetooth for almost zero marginal cost.
Can buy a ready-made wireless system that does the whole job
for under $100.
Doesn't make sense to spend
hundreds of bux on a commercial whiz-bang sw development system.
But I'd rather do it in SW if it's reasonable.
Would save all the hassle of wires and power supplies.
From: Beverly Howard on 14 Apr 2010 12:01
It's not clear what you want to do... process ir received by a
pocketpc's ir receiver or process rs232 data received via a BT device.
In either case, you will need to find or develop a program that will
detect and decode the ir string, then write it to a log file...
For that need, suggest reposting at
otoh, you can get a "killawatt" and track down the individual offenders ;-)
From: mike on 15 Apr 2010 17:37
Beverly Howard wrote:
> It's not clear what you want to do... process ir received by a
> pocketpc's ir receiver or process rs232 data received via a BT device.
I want to detect a single flash of an IR led from the wattmeter, measure
the time since the previous flash and wait for the next flash.
I think I need direct access to the IR detector do do this?
This should be present somewhere on a processor port. I just don't
know which port or how to address ports from a programming language.
Processed data requires some data protocol that isn't present.
Bluetooth is a fallback wireless position:
IR Detector > PIC > RS232 > RS232-BT converter > PocketPC.
Have all the pieces, just don't wanna write the PIC code and have
all the boxes and wires and power supplies to make it work.
Nor do I want to leave it outside in view of the street.
I'm much more fond of my RS232-BT converter than my palm pilot.
> In either case, you will need to find or develop a program that will
> detect and decode the ir string, then write it to a log file...
Not a string. Single flash of the IR led.
> For that need, suggest reposting at
> news://msnews.microsoft.com/microsoft.public.pocketpc.developer or
I'll check it out.
> otoh, you can get a "killawatt" and track down the individual offenders ;-)
killawatt is not practical for things that can't be disconnected:
water heater, air conditioner, 220V stuff, clothes dryer, etc.
Turns out these are the biggest power consumers.
I've already done a power survey of all the unpluggable 110V stuff.
And it's not nearly as fun as building something. Already have a
probe hooked to a laptop and a real
Valhalla digital power analyzer.
Objective for this project is to read the power meter without spending
the $100 for the packaged solution...or mucking around inside the
breaker box with two current probes.
The flashing light is there, let's use it!! ;-)
> Beverly Howard
From: Beverly Howard on 16 Apr 2010 10:30
Again, I am going to direct you to the developers section for this...
In addition you probably need to find a hardware resource as I don't
think that the ppc hardware is going to be able to detect a single
"flash" I'm not well versed on this, but think it may be that the ir
circuit is not going to respond to unmodulated ir sources.
It may be easier to build or look for a "paste on" ir receiver that will
trigger something like a relay, then program to look at the "switch
state" to determine what you need.
Might take a look around for http://vitotechnology.com/ app oscilloscope
(it's no longer on their site) as it allowed looking at ir signals, but
it didn't work on all pocketpc's available at the time. If you can find
it and get it to work on your ppc, you would be able to directly "see"
if spotting the ir pulse is possible.