Battery impulse counter based on PTVO Zigbee firmware with CC2530 and PCF8583 acting as hardware counter

Components:

• CC2530 Module (or E18-TBL-01 Module)
• Photoresistor Module
• PCF8583 Real Time Clock
• 1KΩ Resistor
• 100nF Capacitor
• 3V Battery (like CR2450, CR2032, etc or 2xAA/AAA)
• Prototype board and some wires

Example converter for energy meter with 6400 impulses per kWh. You can change that in lines:

                    power = 1000 * (deltaCount / 6400) * (3600 / deltaTimeSec);

                const energy = val / 6400;