Rhoban ForceFoot V2

Project notes

Resolve the load-cell discrepancy first

The mechanical guide initially describes using 5 kg nominal gauges, but its specific design section describes 40 kg steel cells, references HL703/TAL230A and gives two M4 holes at 27 mm spacing. Those statements must be reconciled against the exact cells and intended robot load; this profile does not silently select one rating. The plate's mounting holes also need matching to the robot. [2]

The guide identifies Autodesk Inventor 2015 designs and links a separate Onshape Sigmaban assembly. We retrieved the original foot.iam and verified its bytes and Git identity; its signature identifies a compound-file container. That does not decode the native geometry, resolve all linked parts or establish fit. The external Onshape assembly was not inspected, and its URL is not proof of a complete verified manufacturing path. [2] [7]

Match electronics options and firmware target

The electronics guide distinguishes TTL/RS485 bus options and three-wire half-bridge versus four-wire full-bridge gauges, with resistor and connection changes. It lists an ATmega328PB, external 16 MHz quartz and HX711 conversion components. The saved Eagle source excerpt and AVR implementation excerpt are inspectable text; no board continuity, rail voltage, sampling noise or bus-level behavior was tested. [3] [5] [6]

For firmware investigation, choose atmega328p or atmega328pb in Makefile.config and match the fuse script to the actual MCU and ISP programmer. The documented build is make, followed by make sendisp for the assumed AVR ISP MkII setup. Those are source instructions, not a reproduced build or safe fuse-setting recommendation for an unknown board. [4]

Readings are not calibrated forces

The guide describes fixed defaults of model 5004, ID 123 and 1,000,000 baud, changed in source rather than on the fly. However, the inspected main.c defines DXL_ID as 124, conflicting with the README's ID 123. Reconcile the selected build and confirm its actual ID before configuring host reads or joining a shared bus; no deployed board's ID was established here. Four signed 24-bit gauge values occupy twelve bytes beginning at register 0x24, with least-significant bytes first. A host must use the right signed decoding and avoid address/ID conflicts in its actual bus. [4] [6]

Offsets are not automatically trimmed or persisted: the user must obtain and save them, then calibrate with known masses and a fitted mapping. Those prerequisites matter before interpreting total weight, support distribution or center of pressure. No calibration, load test, force accuracy, gait integration or current complete cost was established. Rights remain unresolved across the design and firmware layers; this entry supports bounded source investigation, not an unrestricted reuse claim. [3] [4] [6]