Hello.
I'm a complete newbie to electronics, but I've been studying by myself and trying to see if I could design my own energy consumption meter. The idea is simple; the electrical service panel in the house has an LED indicator that blinks 10,000 times for every kWh of electrical energy consumed (once per 0,1 Wh). My circuit consists of a photoresistor that feeds an op amp negative input. The output of the op amp goes into a Schmitt trigger that has a potentiometer for calibrating the comparison voltage (V_COMP) based on ambient lightning, the LED brightness and such. When the LED indicator on the panel lights up, the resistance of the photoresistor goes down, V_IN goes down below V_COMP and V_OUT goes up (ideally to V+? but with VCC of 9 V I'v measured V_OUT at about 7.7 V).
The output of the op amp also goes to an onboard LED indicator (which blinks every time a blink on in the service panel has been detected) and through a 5 V voltage regulator to an Arduino Nano, which counts the blinking frequency and displays the current electricity consumption on an LCD. The idea is to later add a portable display unit that receives the consumption information from the main unit wirelessly (probably RF?), but I'm not that far yet.
I've tested this circuit on a breadboard and it seems to work fine, so I wanted to make a prototype PCB for a proper field test. But before having the PCB manufactured I wanted to see if anyone could have a look at my design and point out all the horrible mistakes and stupid decisions I've made when it comes to the circuit diagram or the PCB.
Thank you in advance.