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Miniature magnetic field probe

A flexible probe under 2 mm wide for mapping magnetic fields inside very small volumes.

  1. 1TLI493D 3-axis Hall sensor (I²C) at the tip of a flexible tail under 2 mm wide, thin enough to reach the centre of the workspace (shown raised here).
  2. 2Control electronics on the same flex PCB, stiffened by a plexiglass plate: PIC16F microcontroller and FTDI USB bridge, streaming measurements to the PC in real time.
  3. 3Electromagnetic system: eight coils focus the field on a workspace of a few millimetres, the volume to be mapped.
  4. 4Positioning arm: moves the probe step by step through the volume to build the field map.
Fig. 1Simplified 3D view, not to scale in detail. Drag to rotate, scroll to zoom.
Category
Medtech & research
Organization
FHNW
Period
2023 – 2026
Technologies
PIC16F, TLI493D, Bare metal C, I²C, USB (FTDI), Flex PCB

Context

Electromagnetic manipulation systems steer magnetic micro-objects with fields focused on a workspace of a few millimetres. Characterising such a field requires a sensor small enough to move inside that volume, and electronics that stream every measurement as the probe is moved point by point.

My role

Designed the probe as a single flexible PCB: a sub-2 mm tail carrying a TLI493D 3-axis I²C Hall sensor, and a control section stiffened by a plexiglass plate, with a PIC16F microcontroller and an FTDI USB bridge. Wrote the bare-metal firmware that reads the sensor and streams the data to the PC over USB in real time.

© 2026 Simon Lemoigne