hi all
we having "load shedding" in our country, sole power supplier cuts mains power different areas daily, 2 hours @ time. ( long story why , public opinion this, not relevant post )
it has been proven voltage of mains supply, when restored supplier, erratic quite time after.
to avoid 'dirty power' damaging home office equipment, wanting use pro mini following when power restored :
1. check mains supply above voltage, , reasonable stable.
2. control restoration of mains power equipment using ssr ( pre-set time delay, 15 minutes )
phase 2 of project option specify time wait, after mains power has stabilized, before restoring power equipment ( in 5 minute increments )
phase 3 add small ethernet module, , link existing diy home automation , control system.
so initial requirement 2 part :
1 - measure mains voltage
2 - control ssr
i grateful if please @ attached drawing, , comment if think may have missed something.
my calculations on voltage divider :
12 vdc = 3.837 v analog input pin
8 vdc = 2.558 v
we having "load shedding" in our country, sole power supplier cuts mains power different areas daily, 2 hours @ time. ( long story why , public opinion this, not relevant post )
it has been proven voltage of mains supply, when restored supplier, erratic quite time after.
to avoid 'dirty power' damaging home office equipment, wanting use pro mini following when power restored :
1. check mains supply above voltage, , reasonable stable.
2. control restoration of mains power equipment using ssr ( pre-set time delay, 15 minutes )
phase 2 of project option specify time wait, after mains power has stabilized, before restoring power equipment ( in 5 minute increments )
phase 3 add small ethernet module, , link existing diy home automation , control system.
so initial requirement 2 part :
1 - measure mains voltage
2 - control ssr
i grateful if please @ attached drawing, , comment if think may have missed something.
my calculations on voltage divider :
12 vdc = 3.837 v analog input pin
8 vdc = 2.558 v
at risk of telling bunch of stuff knew, here's comments:
first, am, voltage number give mains voltage rms value. if same thing are, you're going see greater 12 volts out of transformer. point is... if same thing are, haven't have sized voltage divider resistors properly.
second, think analog input voltage going noisy due ripple. don't think 0.33 uf enough capacitance smooth waveform coming off bridge. different voltage readings depending on in cycle take measurement.
third, trying measure voltage level of unregulated source, while @ same time you're drawing changing amount of energy source. have variable load (ssr on vs. ssr off) on unregulated supply , because of that, going more ripple when turn on ssr. if you're planning draw 7.5 ma off unregulated supply can guarantee 0.33 uf cap isn't enough , voltage you're trying measure going on place. microcontroller going variable load although compared ssr switching off or on, might able ignore microcontroller.
fourth, sure you're going have enough resolution on a/d output resolve you're trying do? account rms voltage , size divider accordingly , calculate theoretical number of bits change you'll have per volt change out @ 220 line? how need , have enough?
fifth, don't care below 220v, you're going burn resolution anyway. maybe need more sophisticated analog front end. concentrate on area care? between 200 , 240? below or above that, don't care actual value... care high or low. maybe more in analog realm before try digitize it?
hope helps?
first, am, voltage number give mains voltage rms value. if same thing are, you're going see greater 12 volts out of transformer. point is... if same thing are, haven't have sized voltage divider resistors properly.
second, think analog input voltage going noisy due ripple. don't think 0.33 uf enough capacitance smooth waveform coming off bridge. different voltage readings depending on in cycle take measurement.
third, trying measure voltage level of unregulated source, while @ same time you're drawing changing amount of energy source. have variable load (ssr on vs. ssr off) on unregulated supply , because of that, going more ripple when turn on ssr. if you're planning draw 7.5 ma off unregulated supply can guarantee 0.33 uf cap isn't enough , voltage you're trying measure going on place. microcontroller going variable load although compared ssr switching off or on, might able ignore microcontroller.
fourth, sure you're going have enough resolution on a/d output resolve you're trying do? account rms voltage , size divider accordingly , calculate theoretical number of bits change you'll have per volt change out @ 220 line? how need , have enough?
fifth, don't care below 220v, you're going burn resolution anyway. maybe need more sophisticated analog front end. concentrate on area care? between 200 , 240? below or above that, don't care actual value... care high or low. maybe more in analog realm before try digitize it?
hope helps?
Arduino Forum > Using Arduino > General Electronics > Measure Mains Voltage and control SSR
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