Designing Conditional Push Notifications for Multi-Sensor IoT Apps in Expo

How to setup React Native / expo push notification according to different types of notification

Developer Pierre is implementing a multi-field monitoring system for farmers using React Native and Expo. The system requires granular notification control where users subscribe to specific sensor alarms across multiple physical locations.

Why This Matters

Technical reality often diverges from simple documentation when handling complex many-to-many relationships between devices and alert triggers. In agricultural monitoring, failing to map device tokens to specific sensor fields results in either notification fatigue or missed critical alarms, directly impacting crop safety.

Key Insights

• Granular subscription management is required for users monitoring up to 6 distinct fields simultaneously.
• Device registration must occur in two stages: initial push token generation and subsequent field-specific interest registration.
• PHP-based backends require a mapping database to link Expo push tokens to specific field IDs for targeted delivery.
• General notifications act as a broadcast channel that must bypass specific field filters to reach all users.
• Sensor threshold alerts must be conditionally routed to only the devices registered for the specific field in alarm.

Practical Applications

• Use case: Agricultural monitoring systems where farmers only receive alerts for active fields like 2, 4, and 5. Pitfall: Failing to update the remote server mapping when a user deselects a field, leading to persistent unwanted alerts.
• Use case: Global system updates sent to all registered smartphones regardless of field settings. Pitfall: Over-reliance on client-side filtering which can lead to missed high-priority general announcements.

References:

• https://dev.to/pierrot10/how-to-setup-expo-push-notification-according-to-different-types-of-notification-12ol