MakerBuddy hardware, clearly documented.

MakerBuddy is an ESP32-based educational and prototyping platform. This page reflects the current MakerBuddy_dev firmware 2.3 source and its WebApp/Chrome 2.5 and MobileApp 1.5.0 clients.

The current MakerBuddy runtime uses Wi-Fi, not Bluetooth, for dashboard communication. Exact ESP32 modules and MakerBuddy PCB revisions can vary; board markings and the schematic for the physical revision remain authoritative.

GPIO 32–35 are ADC1-capable, so these analog readings remain available while Wi-Fi is active. GPIO 2, 5, 12 and 15 have ESP32 boot/input implications; do not repurpose them without checking the board and boot-strapping behavior.

Soil calibration defaults to dry raw 3000 and wet raw 1200. The values are clamped to 0–4095 and calibrated moisture returns 0 if both endpoints are equal.

Ultrasonic readings are accepted only from 2 to 500 cm. An invalid sample retains the previous valid distance; before the first valid result, the value is 999 cm.

RGB values exposed by the APIs are conventional 0–255 intensities. The physical PWM is inverted as 255 - value because the current design uses a common-anode RGB LED.

“Never connect classroom experiments directly to mains electricity. Use the relay only with a suitable low-voltage educational load unless a qualified professional has designed and supervised the installation.

The 16×2 I2C LCD has default rotation and custom-text modes. Firmware checks both custom lines against the physical 16-column limit and supports these live substitutions:

{temp} {humidity} {ds18b20} {light} {gas}
{soil} {distance} {pot} {motion} {button}

Validation uses each wildcard's currently rendered value, not the source token length. This makes a template such as Temp: {temp} practical, but a later, wider sensor value can make an edited template exceed the display width. Sequence LCD strings are stored in 17-byte fields; recognized wildcards are internally encoded to preserve the persisted binary layout.

Ticker callbacks set flags only; sensor, display, persistence and network work runs in the main loop.

Provisioning, Wi-Fi connection attempts, current buzzer pulses and OTA contain blocking paths. They are exceptions to the normal flag-driven design.

On first provisioning, firmware derives MakerBuddy_XXXX from the last two MAC-address bytes, protects the access point with 12345678, and runs wildcard captive DNS at 192.168.4.1. The setup form stores the normalized device name, SSID and password, then restarts.

In station mode, the board attempts three connection batches with up to 20 waits of 500 ms per batch. A successful connection starts the HTTP/WebSocket server and, when a device name exists, advertises <device-name>.local through mDNS. On failure, the firmware disables Wi-Fi and continues standalone rather than falling back automatically to provisioning.

Holding GPIO 5 for 10 seconds clears only the saved network credentials and restores the default LCD mode before restart. Other preferences remain.

All device application traffic is plain HTTP/WS. There is no HTTPS/WSS mode in the current firmware.

The ESP32 stores and executes up to 10 sequences with up to 10 steps each. Supported step actions cover LED on/off/PWM, eight RGB presets/off, buzzer and relay on/off, servo position, and LCD display.

Automation priority is Condition → Timer → Forever → None. A running rule locks only the device used by its current step against lower-priority rules. A timer waiting for its next interval owns no actuator. Condition rules debounce a matching expression for 300 ms; if the condition becomes false mid-cycle, the rule finishes the current cycle before stopping so cleanup actions can run.

Each sensor expression supports a threshold or two comparisons combined with AND/OR. Firmware 2.3 also supports an optional second sensor expression, with another AND/OR joining both complete expressions. Equality is approximate, with an absolute difference below 0.1.

See Documentation for the REST and compact WebSocket sequence formats.

All saved values use the ESP32 Preferences namespace iot-kit.

Sequence writes use dirty/remove bitmasks so only affected slots are rewritten. Runtime fields are reset when records load, and orphaned keys beyond the valid count are removed. The structures in MakerBuddyTypes.h participate in binary storage; reordering or resizing fields requires a deliberate migration.

Potentiometer mapping is loaded or migrated during boot and then deliberately forced to none. Users must select a target again after each restart.

The current source does not use ESP32Servo; servo PWM is generated directly with the Arduino-ESP32 pin-based LEDC API.

lib_deps =
  me-no-dev/ESPAsyncWebServer
  me-no-dev/AsyncTCP
  bblanchon/ArduinoJson@^6.21.3
  adafruit/DHT sensor library
  adafruit/Adafruit Unified Sensor
  paulstoffregen/OneWire
  milesburton/DallasTemperature
  marcoschwartz/LiquidCrystal_I2C

The clients check http://app.makerbuddy.cc/firmware.json and pass a selected binary URL to the board. The firmware then:

1. 1Clears the entire iot-kit Preferences namespace.
2. 2Detaches the sensor, LCD and LED-blink tickers.
3. 3Downloads the supplied URL over HTTP and streams it into the ESP32 updater.
4. 4Shows progress on the LCD and restarts after a successful complete update.

Configuration is cleared before download success is known. A failed OTA therefore still erases Wi-Fi, device identity, rule, calibration, LCD and mapping settings; it also leaves the periodic tickers detached until reboot. OTA URLs are neither origin-restricted nor signature-verified in firmware 2.3.

MakerBuddy firmware 2.3 is designed for a trusted local learning network:

• REST and WebSocket commands have no authentication or authorization.
• HTTP, WebSocket, provisioning and OTA traffic are unencrypted.
• CORS allows all origins and private-network access.
• The provisioning access point uses a fixed password stored in firmware.
• OTA accepts a client-selected HTTP URL without signature validation.

Do not expose port 80 to the public internet. Isolate classroom devices where appropriate, do not use production credentials on the MakerBuddy network, and do not use its readings or controls for medical, industrial, life-critical or certified safety decisions.

The current code supports DHT11, DS18B20, LDR, MQ-2, capacitive soil moisture, HC-SR04, PIR motion, push-button and potentiometer inputs. It controls the onboard single LED, common-anode RGB LED, active buzzer, single-channel relay, SG90-class servo and 1602 I2C LCD.

Third-party modules can differ in voltage, current, signal polarity and connector order even when the plugs look compatible. Check the module datasheet, board labels and exact MakerBuddy PCB revision before connecting an unlisted part.