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[JeffVolp]

I finished my first pass at a schematic, and started looking at the layout.  One issue is that only the largest "XTB-size" Polycase will accept an AC receptacle.  I had wanted to build a smaller module, but that may not be feasible.

One possibility is to custom-machine the blank cover to accept a polarized receptacle rather than the grounded receptacle.  I don't think that is the right approach because I can see this unit being used to monitor power consumed by a grounded device, such as a sump pump.  Does anyone have a problem with the module being 4" x 2.125" x 2.5"?

An alternative might be to use the XPPF case.  With a smart transformerless power supply, it may be possible to squeeze everything onto that size PCB.  That would make the module quite a bit smaller, but the color would be black.

Thoughts?

Jeff

[Knightrider]

Black is fine,  I lived with Ivory only WS units from the shack for years.

I don't think that I'd lose the ground pin.

Smart power supply?  I hope it's smarter than the Cellet.

[JeffVolp]

Smart power supply?

A transformerless power supply uses a capacitor to drop the line voltage to the voltage needed by the unit.  Whatever power is not used by the operating electronics is wasted a heat in a shunt regulator.  The TW523 actually takes advantage of that by having the LED on when the unit is not transmitting, so the energy normally consumed by the LED is available for the transmitter.

A "smart" transformerless supply would have two power levels.  The lower level would provide sufficient energy for the microcontroller.  The second level would provide additional power for the transmitter.  That energy would not normally be dumped into a shunt regulator.  The microcontroller would kick on the second stage when it is transmitting.

Jeff

[Knightrider]

Jeff,

What's the status on this project?  I could probably use one or two of these.

[JeffVolp]

What's the status on this project?  I could probably use one or two of these.

I completed the circuit design and started working on the prototype PCB.  Even simplifying the circuitry as much as possible, it is still almost as complex as the XTBR.  In small quantities, I thought it would be way too expensive for the target market, so I abandoned the project for now.

There are much less expensive "kluges" that can be used to monitor device currents.

Jeff

[Knightrider]

Kludge may be cheaper, but seldom does it provide the satisfaction of completing a JVDE kit.  I'd love to plunk a couple of these into my environmental controls including the heater that i use to defrost the truck in the mornings.

Is $50 each a low end figure for the kit?  How about a plans/parts list and we fend for ourselves?  (do they still sell DIY etching kits?)

Obviously the PIC would have to come from JVDE.

[JeffVolp]

Thank you for the compliment on my kits.

Right now the power monitor is on hold.  The firmware development never got past the concept stage, and nothing was coded.  Maybe in the future...

At the expected volume, the kit would have cost over $50.

Jeff