Need swift dev to fix ble streaming & pdf generation for crane load test app

Category: Mobile Development

Budget: 2755–2755 USDC

I'm the tech lead for an industrial rigging and crane inspection outfit. Our field guys test overhead harbor cranes and bridge hoists by pulling against water bags and calibrated load cells. Right now they're still logging peak tons by hand onto carbon slips and keying it into an old Excel macro later, which is causing transcription errors.

We started building a dedicated iPad app in SwiftUI last month to read real-time tension data over Bluetooth LE from Crosby Straightpoint shackles (transmitting raw hex payloads at 10Hz). The previous freelancer we hired built the UI shells fine, but completely botched the CoreBluetooth packet parsing—they were buffering frames on the main thread, causing severe UI stutter and dropping peak tension spikes, which makes the whole proof test invalid. On top of that, the PDF export for the proof load certificate uses WebKit print rendering and keeps pagination-breaking across table rows.

The app itself is relatively small: 4 screens, local SQLite via GRDB, CoreBluetooth background state, and clean vector-based PDF generation (migrating off WKWebView to UIGraphicsPDFRenderer or PDFKit). The BLE spec from the hardware vendor is fully documented and short (I have the byte mapping sheet ready).

Need someone who actually knows how to handle raw byte stream parsing off the main queue and can generate deterministic multi-page PDF reports. Our annual port authority inspection blitz kicks off on the 14th next month, so I need this rock solid on our iPad minis before field testing.

Skills required

• Swift
• SwiftUI
• CoreBluetooth
• PDFKit
• SQLite
• iOS Development

Milestones are funded into USDC escrow on Polygon before work begins.