Overview
The Notification Center is your real-time alert inbox inside the LoopString dashboard. It keeps you informed when sensors breach the thresholds you have configured, without requiring you to watch the dashboard constantly.
The bell icon in the header bar displays a badge whenever one or more sensors are in an active alert state. Clicking the bell opens the inbox panel where you can review, acknowledge, and dismiss alerts.
How Alerts Flow from Threshold to Notification
Understanding the path an alert takes helps you know where to look when something goes wrong.
First, you configure warning and critical thresholds for a sensor using the inline threshold editor on any SensorStat card. Those thresholds are stored in Firestore and simultaneously mirrored to the Firebase Realtime Database so the Pi can read them locally.
When a sensor reading crosses a threshold, the breach is detected at two places. On the Pi, a Node-RED subflow evaluates the reading against the mirrored threshold and can trigger a local response even without cloud connectivity. In the cloud, a Cloud Function monitors incoming readings and creates a permanent alert event record in Firestore.
The alert event record captures the sensor identity, device, breach direction (above maximum or below minimum), the exact reading value at time of breach, and the severity level (warning or critical).
From that event, notifications are dispatched according to your preferences. An in-app notification is always created. An email is sent if your preferences include email delivery. An SMS is sent for critical alerts if you have SMS enabled on your account tier.
The badge on the bell icon reflects the number of sensors currently in an active alert state. This count comes from the Realtime Database, so it updates within milliseconds of a breach — no page refresh required.
How to Use the Notification Center
Opening the Inbox
Click the bell icon in the top-right area of the header bar. On desktop the inbox opens as a dropdown panel anchored below the bell. On mobile it slides up from the bottom of the screen as a sheet.
If the bell icon is filled and colored red, there is at least one active alert. The number overlaid on the badge shows how many sensors are currently breaching a threshold.
Reading the Inbox
The inbox lists the most recent 50 alert events across all your devices, sorted newest first. Each row shows:
- A colored stripe on the left — red for critical, yellow for warning
- A dot indicator for unread events
- The sensor name and which threshold was crossed
- The reading value at time of breach, converted to your preferred units
- A relative timestamp such as "3m ago" or "2h ago"
Unread events appear with a slightly elevated background. Read events are dimmed.
Navigating to a Card
Clicking any alert row takes you directly to the dashboard view for that device. The page scrolls to the relevant sensor card so you can immediately see the current reading and alarm state. Clicking also marks the event as read.
Marking Alerts Read
To mark a single alert as read, click its row in the inbox.
To mark all alerts as read at once, click the "Mark all read" button in the inbox header. This button only appears when there are unread events.
Acknowledging Alerts
Hovering over an alert row reveals a checkmark button on the right side. Clicking it acknowledges the alert, which stops repeated notifications for that event and records your acknowledgment with a timestamp. Acknowledged alerts can still be viewed in the activity timeline and alert history.
Acknowledging an alert is separate from the alert resolving. An alert resolves automatically when the sensor reading returns to a normal range (past the hysteresis buffer you configured). You can acknowledge an alert that is still active to silence further notifications while you address the issue.
Refreshing the Inbox
The inbox loads the latest data when you open it. A Refresh link at the bottom of the panel lets you pull fresh data without closing and reopening.
Notification Preferences
Open Account Settings and navigate to the Notifications section to configure how and when LoopString contacts you.
Delivery Channel
Choose from three options:
Push and Email sends both an in-browser push notification and an email for every alert. This is the recommended default.
Push only sends browser push notifications but no email.
Email only skips push notifications and sends email only.
In-app notifications appear in the inbox regardless of your channel setting — the inbox is always active.
SMS Notifications
SMS delivery is available for critical alerts on paid subscription tiers. Enable SMS in notification preferences and enter a phone number to receive text messages when a critical threshold is crossed. Warning-level alerts do not trigger SMS.
Quiet Hours
Enable quiet hours to suppress email notifications during a window you define. Push and in-app notifications still arrive during quiet hours — only email is suppressed.
Set a start time and end time using your local timezone. For example, setting 22:00 to 07:00 suppresses overnight emails.
The timezone used for quiet hours is automatically detected from your browser. It is displayed next to the quiet hours settings so you can verify it is correct.
Use Cases
Greenhouse Temperature Monitoring
A grower runs a small greenhouse with a temperature sensor. They configure a critical high threshold at 35 degrees Celsius and a warning high at 30 degrees, with a 1 degree hysteresis on each.
On a hot day the exhaust fan fails. The temperature climbs past 30 degrees and a warning alert fires. The notification center badge shows a count of 1 and the inbox shows the event. The grower receives an email and sees the push notification. They acknowledge the warning while they investigate.
When the temperature climbs above 35 degrees, a critical alert fires. Because the warning was already acknowledged, the critical alert generates a fresh notification. With SMS enabled, a text message arrives immediately on their phone. The grower takes corrective action, opens the dashboard, and manually overrides the fan actuator to restore airflow.
Once the temperature drops back below 34 degrees (35 minus 1 degree hysteresis), the alert resolves automatically and the badge clears.
Overnight Brewing Process
A home brewer ferments beer over several days and wants to be notified only if the fermentation temperature drifts outside a narrow band. They configure a warning at 19 degrees low and 23 degrees high, with quiet hours from 23:00 to 07:00 so overnight emails do not wake them.
At 2 AM the temperature dips to 18.5 degrees. The alert fires, appears in the inbox, and a push notification is delivered. No email is sent because it falls within quiet hours. In the morning the brewer opens the inbox, sees the overnight event, acknowledges it, and adjusts the heating mat setpoint.
Troubleshooting
The badge count does not clear after I close the inbox
The badge count reflects the number of sensors currently in an active alert state, not the number of unread messages. If the underlying sensor reading is still outside its configured threshold, the badge remains active even after you mark all events as read. The badge clears only when the sensor reading returns to a normal state.
Check the sensor card on the dashboard to see the current reading and its alarm color. If the reading is back in range but the badge persists, try refreshing the page to re-establish the Realtime Database connection.
I am not receiving email notifications
First confirm that your notification preference is set to "Push + Email" or "Email only" in Account Settings. Next check whether quiet hours are enabled and whether the alert occurred within your quiet window.
Also check your email spam folder — automated alerts from LoopString can occasionally be filtered. If you are on a free tier, SMS is not available, but email should work. If email still does not arrive, confirm your account email address is verified.
Alerts appear in the inbox but I never got a push notification
Push notifications require browser permission. If you previously denied notification permission in your browser, the in-app inbox will still work but push delivery will not. To restore push notifications, open your browser site settings for the LoopString dashboard URL and re-enable the Notifications permission, then reload the page.
On mobile, make sure the LoopString PWA is installed and that your device notification settings allow alerts from it.
The inbox always shows the same old events
The inbox caches Firestore data for up to five minutes to reduce read costs. Use the Refresh link at the bottom of the inbox panel to pull the latest events immediately. If new alerts consistently fail to appear after refreshing, verify that alert thresholds are configured for the sensor and that the device is online (check the device health panel).
An alert was acknowledged but I keep getting emails
Acknowledgment stops repeated notifications for the same event, but it does not prevent a new alert event from being created if the sensor breaches the threshold again after temporarily recovering. If your sensor oscillates around a threshold value, consider increasing the hysteresis buffer in the threshold editor so the alarm does not fire repeatedly on small fluctuations.
Known Issues and Limitations
The inbox loads the most recent 50 alert events per device. Devices with very high alert frequency may have older events that are not visible in the inbox. Use the Activity Timeline or the full Alert History page for complete historical records.
The SMS feature is only available on paid subscription tiers. Free tier accounts receive in-app and email notifications only.
Quiet hours suppress email delivery only. Push notifications continue to arrive during quiet hours regardless of the quiet hours setting.
Next Steps
- Alarm Thresholds for configuring warning and critical thresholds
- Analytics and History for full alert event history
- Dashboard Overview for navigation guide