Dynamic Demand is a not for profit organisation,  but the chap who is responsible for the meter is Joe Short at demandlogic.co.uk a modest sized company with offices in Hackney.
Who they are   it rather sounds as if the frequency meter is more of a zero-crossing counter lash up, and the basis of a web site gimmick to draw attention to the sort of thing they can do, rather than supposed to be a precision instrument,

 The how explanation  

 they do not warrenty the accuracy


Their big and quite elegant idea is that a simple frequency meter like the one behind the display on the website could be used either within smart appliances or as a stand alone to operate a contactor for load shedding, helping with grid stability.

Right now there is no mechanism for rewarding people for fitting one, but the idea seems a potentially very interesting one - effectively using grid frequency as a near instant signal to manage demand at the load end in much the same way as it already acts as a balancing influence at the rotating generation end. Such an approach will always be faster than anything involving the internet, ADS routers and a some central server a hundred miles away.


If it is just a zero crossing detector then on a noisy supply  it is quite likely to suffer a bit from AM to PM conversion, where voltage spikes or harmonic distortion to the waveforms  that push the centre of the sine wave up or down are detected as if they were  frequency effects, that move the zero crossing sideways. A cleaner but more involved method would be a phase sensitive detector.


Rather fetching animation of making a

square wave from harmonics


a slight alteration of the relative phases and amplitudes  of the harmonics (also helps to visualise why you take a 'good' square wave, and pass it via something like an LC filter that suppresses or phase shifts some but not all of the higher frequencies and it becomes ripply.)

changes the waveshape completely

  The rotating generators on the left represent the harmonics, and the resultant voltage waveform is on the right.

Dynamic Demand is a not for profit organisation,  but the chap who is responsible for the meter is Joe Short at demandlogic.co.uk a modest sized company with offices in Hackney.
Who they are   it rather sounds as if the frequency meter is more of a zero-crossing counter lash up, and the basis of a web site gimmick to draw attention to the sort of thing they can do, rather than supposed to be a precision instrument,

 The how explanation  

 they do not warrenty the accuracy


Their big and quite elegant idea is that a simple frequency meter like the one behind the display on the website could be used either within smart appliances or as a stand alone to operate a contactor for load shedding, helping with grid stability.

Right now there is no mechanism for rewarding people for fitting one, but the idea seems a potentially very interesting one - effectively using grid frequency as a near instant signal to manage demand at the load end in much the same way as it already acts as a balancing influence at the rotating generation end. Such an approach will always be faster than anything involving the internet, ADS routers and a some central server a hundred miles away.


If it is just a zero crossing detector then on a noisy supply  it is quite likely to suffer a bit from AM to PM conversion, where voltage spikes or harmonic distortion to the waveforms  that push the centre of the sine wave up or down are detected as if they were  frequency effects, that move the zero crossing sideways. A cleaner but more involved method would be a phase sensitive detector.


Rather fetching animation of making a

square wave from harmonics


a slight alteration of the relative phases and amplitudes  of the harmonics (also helps to visualise why you take a 'good' square wave, and pass it via something like an LC filter that suppresses or phase shifts some but not all of the higher frequencies and it becomes ripply.)

changes the waveshape completely

  The rotating generators on the left represent the harmonics, and the resultant voltage waveform is on the right.