Saidul Islam BhuiyanScalable Enterprise Software Engineering Book a call

IoT practice

IoT and Bluetooth Low Energy development

Wearables, sensors, POS terminals and access systems that stay fast on the device and keep working when the connection drops.

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In short

We build the device side and the cloud side of IoT products. That includes a Kotlin Bluetooth LE module that keeps seafarers’ smartwatch data syncing with no internet at sea, Android POS ticketing across BRTC’s national bus fleet, MQTT ingestion of Bluetooth and sensor data for Movingwalls’ billboard platform, and 1TB+ of biometric access logs for Suprema BioStar 2.

Devices
BLE wearables, Sunmi POS, sensors
Mobile
Kotlin, React Native
Messaging
MQTT, REST, batch sync
Design goal
Fast on device, light on bandwidth
Starts with
1–2 week sprint, $1k–$2k

IoT and Bluetooth

Wearables, sensors, POS terminals and access systems that stay fast on the device and keep working when the connection drops.

Proven at
  • Ovue ANCORE
  • BRTC
  • Movingwalls
  • Suprema

Bluetooth LE wearables

Kotlin BLE modules with a serialized GATT queue and backoff reconnects that keep syncing offline.

Bluetooth LEKotlin

Android POS and field devices

Ticketing and field apps on Sunmi terminals, with batch sync across a whole fleet.

AndroidSunmi POS

Sensor and MQTT pipelines

Bluetooth, sensor and location data ingested over MQTT into analytics stores.

MQTTMongoDB

Access control and time-series data

Biometric entrance logs at 1TB+ scale, partitioned and indexed for fast queries.

MariaDBSQL Server
Architecture
WearableBLE sensorBLEPHONE APPGATT queueone call at a timeReconnectbackoff, jitterLocal storeworks offlineBackground syncforeground serviceKotlin native module · React Nativewhen onlineIngest APIsmall batchesPostgreSQLreadingsMQTT brokeralways-on devicesSensors, POSalways onlineMQTTAI insightssafety checked
Bluetooth and IoT data path: low latency on the device, low bandwidth to the cloud. Hover or tap a step to see it in the diagram.
  1. 1
    Bluetooth LE devicesWearables and sensors connect over BLE using the vendor’s GATT services.
  2. 2
    Serialized GATT queueOne call at a time, with backoff reconnects, keeps the link fast and stable.
  3. 3
    Offline-first phone appReadings are stored on the phone, and a foreground service keeps sync running.
  4. 4
    Low bandwidth uploadOnly new data goes up, in small batches, whenever a connection appears.
  5. 5
    MQTT for always-on devicesSensors and terminals publish straight to the cloud.
  6. 6
    Checked insightsAI insights pass a safety check before anyone sees them.

Built for Ovue ANCORE crews at sea, BRTC’s bus fleet and Movingwalls billboards.

Bluetooth LEKotlinReact NativeMQTTAndroid POS

When to call us

Signs this is the right time

  • Your Bluetooth connection drops or stalls under load
  • Devices must keep working offline and sync later
  • Field terminals need to sync safely across a whole fleet
  • Sensor data has to reach analytics quickly
  • Time-series data has grown too big for your queries
Web and mobile apps →AI agents and MCP →Backend development →

Questions

Common questions

Anything else is easier to answer on a short call.

How do you keep a Bluetooth LE connection stable?

All GATT operations go through one serialized queue, dropped links reconnect with exponential backoff and jitter, and a foreground service keeps sync running in the background on Android.

Can IoT apps work with no internet connection?

Yes. Readings are stored on the device first and uploaded in small batches when a connection appears, so nothing is lost and bandwidth stays low.

Do you work with MQTT?

Yes. Always-on devices and sensors can publish over MQTT straight to the cloud. We used it to ingest Bluetooth, sensor and location data for a digital billboard platform.

Which devices have you integrated?

Smartwatches through a vendor BLE SDK, Sunmi Android POS terminals, and biometric access-control systems.

Tell us what you need to build or scale.

Engagements start with a 1–2 week discovery sprint, $1,000 to $2,000. Email

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