RFID Asset Search: Mobile App with Movement History

Imagine: a warehouse with 10,000 items, and the needed device hasn't been found for half an hour. Operators run around with paper lists, inventory takes days, and the discrepancy between records and reality reaches 30%. RFID asset tracking with a mobile app solves this: search by EPC takes seconds, movement history is visible in real time, and ERP integration eliminates manual entry. We develop such systems with a full cycle — from event model design to commissioning. Experience: 7+ years and 15+ projects for warehouses, logistics, and manufacturing. Inventory time savings up to 80%, and asset search costs reduced by 3x.

Event Model Architecture

Each tag read is an event with metadata:

data class AssetReadEvent( val epc: String, val readerLocation: String, // antenna/reader ID val timestamp: Long, val rssi: Int, // signal: approximate distance val direction: ReadDirection?, // ENTRY / EXIT for gateway readers val operatorId: String? // who performed manual read ) enum class ReadDirection { ENTRY, EXIT, UNKNOWN } 

The mobile app generates events with operatorId and GPS/indoor coordinates. Gateway readers (Impinj Speedway, Zebra FX9600) generate their events via LLRP or REST API. Everything converges into one event queue on the backend.

How to reduce search costs by 3x?

Manual inventory takes hours, and finding a specific item takes tens of minutes. With our solution, an operator with a mobile reader finds an asset in seconds thanks to EPC filtering and RSSI display. Compare:

Finding a Specific Asset

The most common operation in the mobile app is 'find asset XYZ in this warehouse'. The RFID reader switches to 'proximity search' mode: it shows the RSSI of a specific tag, helping narrow the search area:

class AssetSearchSession( private val rfidReader: RfidReader, private val targetEpc: String ) { private val _proximity = MutableStateFlow(ProximityLevel.UNKNOWN) val proximity: StateFlow<ProximityLevel> = _proximity.asStateFlow() fun start() { rfidReader.setInventoryFilter(epcFilter = targetEpc) // read only target tag rfidReader.startContinuousInventory(onTag = { tag -> if (tag.epc == targetEpc) { _proximity.value = rssiToProximity(tag.peakRSSI) } }) } private fun rssiToProximity(rssi: Int): ProximityLevel = when { rssi > -55 -> ProximityLevel.VERY_CLOSE // < 0.5m rssi > -65 -> ProximityLevel.CLOSE // 0.5–1.5m rssi > -75 -> ProximityLevel.MEDIUM // 1.5–3m else -> ProximityLevel.FAR // > 3m } } 

EPC filter (setInventoryFilter) is critical — without it, the reader reads all tags in range and clogs the data stream. Specific filter APIs depend on the reader SDK: Zebra RFID SDK — SLFlag, TagFilter; Chainway SDK — FilterParam.

Movement History

// Room entities for asset history @Entity(tableName = "asset_events", indices = [Index("epc"), Index("timestamp")]) data class AssetEventEntity( @PrimaryKey(autoGenerate = true) val id: Long = 0, val epc: String, val eventType: String, // "scan", "checkpoint", "entry", "exit" val locationId: String, val locationName: String, val operatorId: String?, val rssi: Int?, val timestamp: Long, val synced: Boolean = false ) @Dao interface AssetEventDao { @Query("SELECT * FROM asset_events WHERE epc = :epc ORDER BY timestamp DESC LIMIT 50") fun getAssetHistory(epc: String): Flow<List<AssetEventEntity>> @Query("SELECT * FROM asset_events WHERE synced = 0 ORDER BY timestamp ASC") suspend fun getUnsynced(): List<AssetEventEntity> } 

History on the device stores only the last N events. Full history is on the server. WorkManager syncs unsynced events when network is available.

Why we guarantee up to 99% accuracy?

We use proven SDKs, stable protocols, and test on real equipment. Without RSSI and direction analysis, it's impossible to distinguish an asset passing by a gate from it temporarily being in the zone. Our algorithms consider both parameters. Additionally, we use the EPC Gen2 standard for tag compatibility. Reducing accounting errors leads to direct cost savings.

Comparison of Popular RFID Readers

Integration with ERP/WMS

Asset tracking without integration with an accounting system is half a solution. REST API for synchronization:

interface AssetTrackingApi { @POST("events/batch") suspend fun pushEvents(@Body events: List<AssetEventDto>): Response<BatchResult> @GET("assets/{epc}") suspend fun getAssetInfo(@Path("epc") epc: String): Response<AssetInfoDto> @GET("assets/{epc}/location") suspend fun getLastKnownLocation(@Path("epc") epc: String): Response<LocationDto> } 

getLastKnownLocation — for verification: the operator scans the tag, the app immediately shows where the system last saw it. A mismatch between actual and system location is a red flag for logistics.

How does WMS integration proceed?

Step 1: Audit current processes and identify critical control points. Step 2: Configure stationary readers and LLRP gateway for event collection. Step 3: Develop REST API for synchronization — we adapt it to your ERP (1C, SAP, Oracle). Step 4: Deploy the mobile app with search and history modules. Final stage: testing on real assets and operator training. The entire cycle takes 2 to 4 weeks. Get a consultation for your scenario — we help choose the optimal solution.

What's Included

• Process analysis and RFID equipment selection.
• Mobile app development (iOS/Android) with search and history modules.
• Configuration of stationary readers and LLRP gateway.
• Server-side event bus and REST API.
• Integration with your ERP/WMS (1C, SAP, Oracle, etc.).
• Testing on real assets.
• Documentation and operator training.
• 3-month warranty support.

A common mistake at the start is trying to save on readers and using cheap antennas without field tuning. This leads to 'dead zones' and missed reads. We conduct a pre-project survey and guarantee coverage.

Timeline

Mobile asset search app + event history + REST sync with WMS: 5 days. Full solution including stationary Impinj/Zebra reader setup, LLRP integration, and server-side event bus: 2–4 weeks.

Assess your project — get a free consultation on technology stack and timelines. Contact us, and we will offer a turnkey optimal solution.