[chbot] Cheap arduino follow up.

Chris Hellyar chris at trash.co.nz
Fri Nov 14 22:01:11 GMT 2014

(re-sent, got moderated due to attachment :-) )

Photo, thousand words: http://logicalit.biz/forumimages/141114powermeter.jpg

Random follow-up on the cheap Arduino thread a wee while ago.

The $2.38 USD Arduino Micro Pro's turned up a couple of weeks ago, and 
I've just used the first of them...

Quality wise they're fine, would prefer routed edges on the PCB's, as 
they are a bit rough, but that's just a cosmetic issue.

I managed to kill one by applying 13.8Vdc to the VCC pin, which is not 
an issue with the board itself.

The 5V regulator on-board shows 5.12V on VCC with 12.9V input, but 
that's outside spec for the device so probably giving the wee SMD 
regulator a bit of a hard time.  (With 9V it showed 4.99V)

The gadget in the pic is an in-line current/voltage/power meter that 
runs a remote LCD screen via I2C (the white cable).  Uses a 30A hall 
effect sensor module for current.  Calculates and displays Wh/Ah and 
peak/avg/low  power/voltage/current etc.

The wee Arduino is ideal for this as it's a one-off for testing 
something and I wanted to fit the unit inside some heatshrink hidden 
away inside a cabinet.

Due to the 5.12V issue mentioned above there is a 78L05 regulator on the 
back of the veroboard to keep the Voltage reading withing reasonable 

No issues using these with an FT232 usb- TTL serial converter and the 
arduino software recognises them without any issues..

Excellent value for money if you need to add a small brain to a project 
at very much throw-away cost level.

Cheers, Chris H.

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