diff --git a/main.c b/main.c
index 5d55eb2..318cf64 100644
--- a/main.c
+++ b/main.c
@@ -39,6 +39,7 @@
 #include "global.h" // board definitions
 #include "usart.h" // USART utilities
 #include "usb_cdcacm.h" // USB CDC ACM utilities
+#include "sensor_pzem.h" // PZEM electricity meter utilities
 
 /** @defgroup main_flags flag set in interrupts to be processed in main task
  *  @{
@@ -164,6 +165,13 @@ void main(void)
 	ticks_time = rtc_get_counter_val(); // get time/date from internal RTC
 	printf("current time: %02lu:%02lu:%02lu\n", ticks_time/(60*60), (ticks_time%(60*60))/60, (ticks_time%60)); // display time
 
+	// setup PZEM electricity meter
+	printf("setup PZEM-004 electricity meter: ");
+	sensor_pzem_setup(); // setup PZEM electricity meter
+	printf("OK\n");
+
+	sensor_pzem_measurement_request(0xc0a80101, VOLTAGE);
+
 	// main loop
 	printf("command input: ready\n");
 	bool action = false; // if an action has been performed don't go to sleep
@@ -200,6 +208,27 @@ void main(void)
 				}
 			}
 		}
+		while (sensor_pzem_measurement_received) { // measurement from electricity meter received
+			struct sensor_pzem_measurement_t measurement = sensor_pzem_measurement_decode(); // decode measurement
+			if (measurement.valid) { // only show valid measurement
+				switch (measurement.type) {
+				case VOLTAGE:
+					printf("voltage: %.01f V\n", measurement.value.voltage);
+					break;
+				case CURRENT:
+					printf("current: %.02f A\n", measurement.value.current);
+					break;
+				case POWER:
+					printf("power: %.00f W\n", measurement.value.power);
+					break;
+				case ENERGY:
+					printf("energy: %lu Wh\n", measurement.value.energy);
+					break;
+				default:
+					break;
+				}
+			}
+		}
 		while (button_flag) { // user pressed button
 			action = true; // action has been performed
 			printf("button pressed\n");
@@ -234,5 +263,5 @@ void rtc_isr(void)
 {
 	rtc_clear_flag(RTC_SEC); // clear flag
 	rtc_internal_tick_flag = true; // notify to show new time
-	//led_toggle(); // blink every second to show the firmware is running
+	led_toggle(); // blink every second to show the firmware is running
 }