Ouch, and another ouch since you seem to live in a 220VAC country. You can't just connect 220V to a voltage regulator---it has maximum allowed input voltage around 35V---you'd exceed that by a factor of almost 10.
You probably should either do some reading about line voltage electronics and 220V power supplies (hint---what you propose could work if you used a transformer to get 220V down to 12V or so). My suggestion to you would be to consider a low-cost commercial power meter like Kill-A-Watt ($20 or so) then point a BBB with a webcam at its display, and do a little image processing to read out the power. People also cracked them open and interfaced directly to their internal circuitry. On Wed, Oct 30, 2013 at 2:57 PM, <[email protected]> wrote: > I'd like to use my BeagleBone Black to build a small power efficiency > station for my school. For that I plan to measure power consumption using a > current transformer and a voltage transformer, feed the data into a small & > fast database and show it through a web interface to the school staff. > I see that 50 Hz are not a problem for BB ADCs, but I'm not sure at all > using them is a good idea. > Intially I planned to use the same voltage I must measure to power the BB. > I'm starting from a circuit like the attached one (replacing the UA78M33 by > a UA7805CKCT which provides up to 1.5 A output) > > > <https://lh4.googleusercontent.com/-Rh9IrbXEzAU/UnFV0UcdTSI/AAAAAAAAEAM/TduMV2A5CT4/s1600/adc.jpg> > > Changing the R1/R2 divisor I can make the 220V signal lower , but I'd > always get a signal with a negative side (-0.9V - +0.9V) in the best case. > Same for the current transformer, after applying its output to a 100 ohms > resistor. So, first, is it an awful idea to use BB for this purpose? If > not, how can I avoid the negative part of the signal before feeding the BB > ADCs? > > Thanks in advance > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
