smabo-esp32 — smabo Guide

Roadmap#

This page is the guide for the 'smabo-esp32' node on the roadmap below.

This guide assumes you have completed the Base Parts guide.

Overview#

This page explains how to set up smabo-esp32.

smabo-esp32 is responsible for:

Controlling sensors and actuators connected to the ESP32

Required Parts#

The following parts are required to implement this feature.

Part	Product URL	Notes
ESP32-DevKitC	link	Compatible alternatives OK
Breadboard (SAD101)	link	Standard breadboards have 5 holes per row, but this one has 6 — required for the ESP32's width.
Jump wires	link	-
Battery box (AA ×4, battery-snap compatible)	link	Battery snap version is recommended for easier handling.
Battery snap (for battery box)	link	A version with connector pins is recommended — easier to insert into the breadboard and less likely to come loose.
Rechargeable AA batteries × 4	link	Rechargeable batteries are recommended.
Battery charger	link	-
Servo motor driver PCA9685	link	Compatible alternatives OK, but only needed if implementing Hand / Neck / Robot Arm features.
Mini breadboard	link	Choose one with an adhesive backing.
TB6612FNG dual motor driver	link	Compatible alternatives OK (though a version without pre-soldered pin headers will require soldering yourself). Only needed if implementing Mobile Robot / Encoder Mobile Robot features.

Setting Up smabo-esp32#

Installing Thonny (Flash Tool)#

Download and install Thonny for your OS from:

https://thonny.org/

Once installation is complete, launch Thonny.

Flashing the Source Code

Connect the ESP32 to your PC via USB, then click the bottom-right button and select 'MicroPython (ESP32)'.

Thonny — select interpreter

Select all Python files inside 'smabo-esp32', right-click and choose 'Upload to /' to flash them to the ESP32.

Thonny — upload source

Flashing the Config File

Next, flash the config file.

From the config directory, select the JSON file matching your ESP32 model and copy it as 'config.json'.

Copy config file

Fill in the following fields for your environment:

wifi/ssid — SSID of the network to connect to
wifi/password — password of that network

WiFi frequency note

ESP32 only supports 2.4 GHz WiFi.

SSIDs ending in 'G' (e.g., Buffalo-G-xxxx) are 2.4 GHz

SSIDs ending in 'A' (e.g., Buffalo-A-xxxx) are 5 GHz

Use the 'G' SSID here.

Config WiFi and IP settings

Once you have filled in the settings, flash config.json to the ESP32 the same way you flashed the source code.

Upload config to ESP32

3D Printing Parts#

Print the newly added parts on your 3D printer.

Because slicer software varies by printer model, only key points are noted here rather than step-by-step slicer instructions.

Print the following parts oriented as shown in the images.

Printing tips

Orient the convex parts sideways to prevent breakage at the base when attaching/detaching.

Always enable support material.

smabo-hardware/stl/base/bread_board_stopper_bottom_l.stl

smabo-hardware/stl/base/bread_board_stopper_bottom_r.stl

smabo-hardware/stl/base/bread_board_stopper.stl

smabo-hardware/stl/base/mini_bread_boad_stand.stl

smabo-hardware/stl/base/pca9685_stopper_l.stl

smabo-hardware/stl/base/pca9685_stopper_r_bottom.stl

smabo-hardware/stl/base/pca9685_stopper_r_top.stl

[Optional] smabo-hardware/stl/base/in_base_plate_wire_hole.stl
- This part can be used as an internal divider inside smabo.

About the Breadboard#

The SAD101 ships with a jumper wire inserted in the middle of the + rail.

In smabo, the + rail is split into two zones:

Right side of + rail → 6 V (battery box)
Left side of + rail → 5 V (ESP32 output)

Breadboard power rails

Therefore, remove the factory-installed jumper wire in the center of the + rail.

Remove jumper wire

Inside the breadboard

Looking at the back of the breadboard, you can see metal strips running along each row.

Any holes connected to the same strip are electrically connected, so multiple jump wires inserted in those holes form a circuit.

On the SAD101 in particular, the + rail is split in the middle — left and right are separate. The factory jumper wire was there to bridge them into one continuous rail.

Because we use different voltages on each side, that jumper must be removed.

Assembly#

Assemble the required parts as shown in the video below.

Note: the video also includes parts printed in previous steps.

Assembly tips

Use the printed parts to mount the breadboard, PCA9685, and mini breadboard. Pay particular attention to the following:

Insert the ESP32 into the left end of the breadboard.

Attach the mini breadboard using its adhesive backing.

Place the battery box inside smabo and route only the jump wires outside, connecting them to the breadboard.

Wiring positions are explained in the Wiring section below.

Wiring#

About the breadboard + rail

Always remove the + rail jumper wire that came with the SAD101. Leaving it in may damage the ESP32 and actuators.

For this step we are not yet driving any actuators, so only the battery wiring is needed as preparation for later steps.

In the table below, "Point A" and "Point B" are directly connected in the circuit.

Point A	Point B	Notes
Battery box (+)	Breadboard + rail (right side)	Right rail = 6 V; do not mix with 5 V side
Battery box (-)	Breadboard - rail	-
ESP32 5 V pin	Breadboard + rail (left side)	Left rail = 5 V; do not mix with 6 V side
ESP32 GND	Breadboard - rail	-

As noted above, the left and right sides of the + rail carry different voltages.

Mixing 6 V and 5 V on the same rail half will damage the ESP32 and actuators.

Please wire carefully.

Wiring diagram for ESP32-DevKitC:

Wiring diagram

Operation#

Startup Procedure#

Follow the startup procedure here.

Setup is complete once all programs start and communication is confirmed.

Next#

Next, follow the guide for:

🔌 smabo-esp32