Sesame Robot

Four boards, four wiring and firmware paths

The main decision is the controller, because wiring, power and firmware settings all follow from it:

• Lolin ESP32-S2 Mini on a protoboard. Recommended for DIY builds. It uses the core BOM plus wiring option A (protoboard, headers and a buck converter rated for a stable 5 V / 3 A output), and the rails need at least 5 V at 3 A from USB-C PD or a battery. [S001] [S004] [S005]
• Sesame Distro Board V3.1 (ESP32-S3). The current board, with a Bambu Lab battery connector. Built from scratch, its SMD parts need advanced soldering or a PCB assembly service. Build kits include an assembled, pre-flashed Distro Board, described upstream as V3 or earlier V2, so confirm the revision with the supplier before relying on the V3.1 fixes or choosing a power route. The PCB notes say its 12 V USB-C PD negotiation is "slightly untested". The original V3 had USB interference and a reversed battery connector, both fixed in V3.1. [S005]
• Distro Board V2. Legacy; battery brownouts restrict it to USB power unless a separate buck converter is soldered onto the power line, as the PCB notes describe. [S004] [S005]
• Distro Board V1 with an ESP32-DevKitC-32E. Legacy; cannot run on tethered USB-C power. [S004]

The firmware guide asks you to select the matching board in Arduino IDE and uncomment the matching servo-pin block. It also pins ESP32Servo to v3.0.9 because newer releases have a known multi-channel issue. Buying servos that are not the 180-degree MG90S variant is flagged as a build-breaking mistake. [S004] [S007]

Reconcile the guides before printing

Several upstream documents disagree in small but practical ways. The build guide's parts checklist mentions two 14500 cells in an AAA holder, while the BOM recommends a Bambu Lab 14500 7.4 V 800 mAh pack and a reprinted internal frame. The printing guide recommends "Enclosed v91", the top-cover notes describe "Enclosed v100", and the pinned STL is named v117. The CAD sources are labelled v122 while the STLs are v117 and v121; we did not compare their geometry. The build guide also links a motor-testing page under hardware/, but the pinned archive has it at the top-level motor-testing/README.md. [S004] [S006] [S008] [S009]

Calibration happens with every joint removed so each motor shaft spins freely, using the motor tester on DIY and V1 builds or the pre-flashed portal on kit boards. The build guide then fits each hip at 45 degrees while the motors hold STAND, checks that REST brings it parallel to the body, and only then fastens it; leg joints follow the same check for collisions. [S006]

Cost and licensing scope

The README and the maintainer's page both give about USD 50–60 in hardware components. A 3D printer is listed as a separate requirement. That range is not itemized, and it does not name a controller route or a date. The BOM links point to representative Amazon searches and note that prices change often. Whether it covers tools, filament, shipping or taxes is not established, so budget for those separately and treat the range as a rough parts figure, not a delivered quote. [S001] [S004] [S010]

The repository has one license file, Apache License 2.0, at its root, and the maintainer describes Sesame as Apache 2.0. The pinned archive contains Fusion 360 and STEP sources, STLs, Distro Board Gerbers (EasyEDA sources for V2 and V3.1), firmware and Sesame Studio. Purchased modules and external Arduino libraries keep their own terms. The companion app, simulator and ML tools are separate projects and were not reviewed here. [S001] [S003] [S009] [S010]

No part of this profile comes from a physical build, flashing session or walking test. Dimensions, battery runtime and gait performance remain unverified.