diff --git a/components/BTlib/BTlib_nimble.c b/components/BTlib/BTlib_nimble.c
index aa88d9d..39ecbde 100644
--- a/components/BTlib/BTlib_nimble.c
+++ b/components/BTlib/BTlib_nimble.c
@@ -37,10 +37,8 @@ static int gatt_svr_chr_access_hum(uint16_t conn_handle, uint16_t attr_handle, s
 static int gatt_svr_chr_access_batt_level(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg);
 
 static int gatt_svr_chr_access_power_voltage(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg);
-static int gatt_svr_chr_access_power_pin(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg);
-static int gatt_svr_chr_access_power_pout(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg);
-static int gatt_svr_chr_access_power_format(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg);
 
+static int gatt_svr_chr_access_magfield_update(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg);
 static int gatt_svr_chr_access_magfield_x(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg);
 static int gatt_svr_chr_access_magfield_y(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg);
 static int gatt_svr_chr_access_magfield_z(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg);
@@ -97,14 +95,6 @@ char_pres_format_t voltage_char_pres_format = {
 	.descr = NSP_DESC_MAIN,
 };
 
-char_pres_format_t power_char_pres_format = {
-	.format = FORMAT_INT16,
-	.exponent = -3,
-	.unit = POWER_UNIT_UUID,
-	.namespc = 1,
-	.descr = NSP_DESC_MAIN,
-};
-
 char_pres_format_t magfield_char_pres_format = {
 	.format = FORMAT_INT32,
 	.exponent = -12,
@@ -243,42 +233,20 @@ static struct ble_gatt_svc_def gatt_svr_svcs[] = {
 					{ 0 },
 				},
 			},
-			[POWER_CHAR_PIN] = {
-				.uuid = BLE_UUID16_DECLARE(ALIM_POWER_IN_UUID),
-				.access_cb = gatt_svr_chr_access_power_pin,
-				.val_handle = &pow_handle[POWER_CHAR_PIN],
-				.flags = BLE_GATT_CHR_F_READ,
-				.descriptors = (struct ble_gatt_dsc_def[]){
-					{
-						.uuid = BLE_UUID16_DECLARE(CHAR_PRES_FORMAT),
-						.att_flags = BLE_ATT_F_READ,
-						.access_cb = gatt_svr_chr_access_power_format,
-					},
-					{ 0 },
-				},
-			},
-			[POWER_CHAR_POUT] = {
-				.uuid = BLE_UUID16_DECLARE(ALIM_POWER_OUT_UUID),
-				.access_cb = gatt_svr_chr_access_power_pout,
-				.val_handle = &pow_handle[POWER_CHAR_POUT],
-				.flags = BLE_GATT_CHR_F_READ,
-				.descriptors = (struct ble_gatt_dsc_def[]){
-					{
-						.uuid = BLE_UUID16_DECLARE(CHAR_PRES_FORMAT),
-						.att_flags = BLE_ATT_F_READ,
-						.access_cb = gatt_svr_chr_access_power_format,
-					},
-					{ 0 },
-				},
-			},
 			{ 0 },
 		},
 	},
-	[MAGFIELD_SVC_UUID] = {
+	[MAGFIELD_SVC_IDX] = {
 		// magnetic field measure (debug?)
 		.type = BLE_GATT_SVC_TYPE_PRIMARY,
 		.uuid = BLE_UUID32_DECLARE(MAGFIELD_SVC_UUID),
 		.characteristics = (struct ble_gatt_chr_def[]){
+			[MAGFIELD_UPDATE] = {
+				.uuid = BLE_UUID16_DECLARE(MAGFIELD_UPDATE_UUID),
+				.access_cb = gatt_svr_chr_access_magfield_update,
+				.val_handle = &magfield_handle[MAGFIELD_UPDATE],
+				.flags = BLE_GATT_CHR_F_WRITE,
+			},
 			[MAGFIELD_CHAR_X] = {
 				.uuid = BLE_UUID16_DECLARE(MAGFIELD_X_UUID),
 				.access_cb = gatt_svr_chr_access_magfield_x,
@@ -322,7 +290,7 @@ static struct ble_gatt_svc_def gatt_svr_svcs[] = {
 				},
 			},
 			{ 0 },
-		},
+		}
 	},
 	{ 0 },
 };
@@ -446,75 +414,96 @@ static int gatt_svr_chr_access_power_voltage(uint16_t conn_handle, uint16_t attr
 }
 
 
-static int gatt_svr_chr_access_power_pin(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg){
+
+static int gatt_svr_chr_access_magfield_x(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg){
 	int rc = 0;
 
-	ESP_LOGI(NIMBLE_LOG_TAG, "batt power access event");
+	ESP_LOGI(NIMBLE_LOG_TAG, "magfield x access event");
 
 	switch(ctxt->op){
 		case BLE_GATT_ACCESS_OP_READ_CHR:
 		{
-			update_power_inout_readings(main_app_conf->power_conf->data);
-			uint16_t powerin = main_app_conf->power_conf->data->pin;
-			rc = os_mbuf_append(ctxt->om, &powerin, sizeof(powerin));
-		}
-		break;
-		case BLE_GATT_ACCESS_OP_READ_DSC:
-		{
-			uint16_t uuid = ble_uuid_u16(ctxt->dsc->uuid);
-			switch(uuid){
-				case CHAR_PRES_FORMAT:
-					rc = os_mbuf_append(ctxt->om, &voltage_char_pres_format, 7);
-				break;
-			}
+			int32_t bx = main_app_conf->power_conf->data->bx;
+			rc = os_mbuf_append(ctxt->om, &bx, sizeof(bx));
 		}
 		break;
 	}
 	return rc == 0 ? 0 : BLE_ATT_ERR_INSUFFICIENT_RES;
 }
-static int gatt_svr_chr_access_power_pout(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg){
+static int gatt_svr_chr_access_magfield_y(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg){
 	int rc = 0;
 
-	ESP_LOGI(NIMBLE_LOG_TAG, "batt power access event");
+	ESP_LOGI(NIMBLE_LOG_TAG, "magfield y access event");
 
 	switch(ctxt->op){
 		case BLE_GATT_ACCESS_OP_READ_CHR:
 		{
-			update_power_inout_readings(main_app_conf->power_conf->data);
-			uint16_t powerout = main_app_conf->power_conf->data->pout;
-			rc = os_mbuf_append(ctxt->om, &powerout, sizeof(powerout));
-		}
-		break;
-		case BLE_GATT_ACCESS_OP_READ_DSC:
-		{
-			uint16_t uuid = ble_uuid_u16(ctxt->dsc->uuid);
-			switch(uuid){
-				case CHAR_PRES_FORMAT:
-					rc = os_mbuf_append(ctxt->om, &voltage_char_pres_format, 7);
-				break;
-			}
+			int32_t by = main_app_conf->power_conf->data->by;
+			rc = os_mbuf_append(ctxt->om, &by, sizeof(by));
 		}
 		break;
 	}
 	return rc == 0 ? 0 : BLE_ATT_ERR_INSUFFICIENT_RES;
 }
-static int gatt_svr_chr_access_power_format(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg){
+static int gatt_svr_chr_access_magfield_z(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg){
+	int rc = 0;
+
+	ESP_LOGI(NIMBLE_LOG_TAG, "magfield z access event");
+
+	switch(ctxt->op){
+		case BLE_GATT_ACCESS_OP_READ_CHR:
+		{
+			int32_t bz = main_app_conf->power_conf->data->bz;
+			rc = os_mbuf_append(ctxt->om, &bz, sizeof(bz));
+		}
+		break;
+	}
+	return rc == 0 ? 0 : BLE_ATT_ERR_INSUFFICIENT_RES;
+}
+static int gatt_svr_chr_access_magfield_format(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg){
 	int rc = 0;
 
 	if(ctxt->op != BLE_GATT_ACCESS_OP_READ_DSC){
 		ESP_LOGE(NIMBLE_LOG_TAG, "wrong callback called");
 	}
 
-	ESP_LOGI(NIMBLE_LOG_TAG, "batt voltage  pres access event");
+	ESP_LOGI(NIMBLE_LOG_TAG, "magfield  pres access event");
 
 	uint16_t uuid = ble_uuid_u16(ctxt->dsc->uuid);
 	switch(uuid){
 		case CHAR_PRES_FORMAT:
-			rc = os_mbuf_append(ctxt->om, &power_char_pres_format, 7);
+			rc = os_mbuf_append(ctxt->om, &magfield_char_pres_format, 7);
 		break;
 	}
 	return rc == 0 ? 0 : BLE_ATT_ERR_INSUFFICIENT_RES;
 }
+static int gatt_svr_chr_access_magfield_update(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg){
+	int rc = 0;
+
+	if(ctxt->op != BLE_GATT_ACCESS_OP_WRITE_CHR){
+		ESP_LOGE(NIMBLE_LOG_TAG, "magfield update wrong callback called");
+		return 0;
+	}
+
+	ESP_LOGI(NIMBLE_LOG_TAG, "magfield update access event");
+
+	uint8_t command;
+	rc = ble_hs_mbuf_to_flat(ctxt->om, &command, 1, NULL);
+  if (rc != 0) {
+  	return BLE_ATT_ERR_UNLIKELY;
+  }
+
+	switch(command){
+		case 0:
+			update_magfield_readings(main_app_conf->power_conf->data);
+		break;
+		case 1:
+			update_magfield_readings_cal(main_app_conf->power_conf->data);
+		break;
+	}
+	
+	return rc == 0 ? 0 : BLE_ATT_ERR_INSUFFICIENT_RES;
+}
 
 static void ble_advertise(void){
 	main_app_conf->sensor->enabled = false;
diff --git a/components/BTlib/include/BTlib_nimble.h b/components/BTlib/include/BTlib_nimble.h
index 0b22f60..a479efd 100644
--- a/components/BTlib/include/BTlib_nimble.h
+++ b/components/BTlib/include/BTlib_nimble.h
@@ -38,6 +38,7 @@
 #define MAGFIELD_X_UUID 0x3B91
 #define MAGFIELD_Y_UUID 0x23E8
 #define MAGFIELD_Z_UUID 0x7F84
+#define MAGFIELD_UPDATE_UUID 0x5D4B
 
 #define DEFAULT_NAME "CO2_ble"
 #define DEFAULT_NAME_LEN 7
@@ -167,12 +168,11 @@ struct batt_level_char_descr {
 
 enum{
 	POWER_CHAR_VOLTAGE,
-	POWER_CHAR_PIN,
-	POWER_CHAR_POUT,
 	POWER_CHAR_NB,
 };
 
 enum{
+	MAGFIELD_UPDATE,
 	MAGFIELD_CHAR_X,
 	MAGFIELD_CHAR_Y,
 	MAGFIELD_CHAR_Z,
diff --git a/components/power_inout/CMakeLists.txt b/components/power_inout/CMakeLists.txt
new file mode 100644
index 0000000..688613f
--- /dev/null
+++ b/components/power_inout/CMakeLists.txt
@@ -0,0 +1,3 @@
+idf_component_register(SRCS "power_inout.c"
+                    INCLUDE_DIRS "include"
+                    REQUIRES nvs_flash MMC56x3)
diff --git a/components/power_inout/include/power_inout.h b/components/power_inout/include/power_inout.h
new file mode 100644
index 0000000..800379b
--- /dev/null
+++ b/components/power_inout/include/power_inout.h
@@ -0,0 +1,25 @@
+#ifndef POWER_DATA_H
+#define POWER_DATA_H
+
+#include "nvs_flash.h"
+
+struct power_data {
+  int32_t bx, by, bz;
+  int32_t bridge_offset[3];
+};
+typedef struct power_data power_data_t;
+
+struct power_conf {
+  power_data_t* data;
+};
+typedef struct power_conf power_conf_t;
+
+void get_current_inout(int32_t in, int32_t out);
+void update_power_inout_readings(power_data_t* data);
+power_conf_t* get_power_configuration(nvs_handle_t nvs);
+void update_bridge_offset(power_data_t* data);
+
+void update_magfield_readings(power_data_t* data);
+void update_magfield_readings_cal(power_data_t* data);
+
+#endif
diff --git a/components/power_inout/power_inout.c b/components/power_inout/power_inout.c
new file mode 100644
index 0000000..93a619a
--- /dev/null
+++ b/components/power_inout/power_inout.c
@@ -0,0 +1,33 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "power_inout.h"
+
+#include "MMC56x3.h"
+
+power_conf_t* get_power_configuration(nvs_handle_t nvs){
+  power_conf_t* conf = malloc(sizeof(power_conf_t));
+  power_data_t* data = malloc(sizeof(power_data_t));
+  conf->data = data;
+  return conf;
+}
+
+void update_magfield_readings(power_data_t* data){
+  int32_t bx, by, bz;
+  MMC56x3_get_mag_field(&bx, &by, &bz);
+  MMC56x3_to_pT(bx, by, bz, &data->bx, &data->by, &data->bz);
+}
+
+void update_magfield_readings_cal(power_data_t* data){
+  int32_t bx, by, bz;
+  MMC56x3_get_mag_field(&bx, &by, &bz);
+  bx+=data->bridge_offset[0];
+  by+=data->bridge_offset[1];
+  bz+=data->bridge_offset[2];
+  MMC56x3_to_pT(bx, by, bz, &data->bx, &data->by, &data->bz);
+}
+
+void update_bridge_offset(power_data_t* data){
+  MMC56x3_get_bridge_offset(&data->bridge_offset[0], &data->bridge_offset[1], &data->bridge_offset[2]);
+  MMC56x3_set();
+}
diff --git a/main/CO2_Sense.c b/main/CO2_Sense.c
index 036dec3..c7f16c4 100644
--- a/main/CO2_Sense.c
+++ b/main/CO2_Sense.c
@@ -18,6 +18,7 @@
 #include "driver/i2c.h"
 
 #include "ledController.h"
+#include "power_inout.h"
 #include "scd4x_i2c.h"
 #include "sdkconfig.h"
 #include "sensirion_i2c_hal.h"
@@ -45,7 +46,7 @@ void app_main(void){
 		.min_freq_mhz = 40,
 		.light_sleep_enable = true, // enable light sleep
 	};
-	//ESP_ERROR_CHECK(esp_pm_configure(&pm_config));
+	ESP_ERROR_CHECK(esp_pm_configure(&pm_config));
 
 	configuration_data_t* conf = malloc(sizeof(configuration_data_t));
 	init_conf_from_nvs(conf);
@@ -61,18 +62,13 @@ void app_main(void){
 
 	init_battery_level_adc(conf->battery_conf);
 
-	MMC56x3_set();
-	MMC56x3_reset();
 	uint8_t id=0;
 	MMC56x3_get_product_ID(&id);
 	uint8_t temp;
 	MMC56x3_get_temperature(&temp);
-	int32_t offx, offy, offz;
-	MMC56x3_get_bridge_offset(&offx, &offy, &offz);
-	MMC56x3_set();
 	ESP_LOGI("MAIN", "MMC5603 product id %d", id);
 	ESP_LOGI("MAIN", "MMC measured temp is %d", temp);
-	ESP_LOGI("MAIN", "MMC bridge offset; x %ld, y %ld, z %ld", offx, offy, offz);
+	update_bridge_offset(conf->power_conf->data);
 	
 	init_scd4x();
 	scd4x_power_down();