Home-Assistant-Dev/YAML Examples/WREN C5

WREN | ESP32-C5 Recliner Linear Motor Controller | IoT Home Automation

WREN C5 - ESPHome Example Code

This is a working development code for WREN, within Home Assistant.

Code Development

Being primarily a hardware engineer and not understanding YAML, I have enlisted some help.

Have used the help of GROK and ChatGPT in the process of understanding more on AI help and importantly ESPHome YAML. Then after a number of iterations, learning and testing, I have formed a working 'wren-c5-esphome' code.

The important point of the code is to read the controller inputs, drive the motors and importantly recognise a fault condition.

Basic Examples

During development, I took baby steps in understanding how YAML worked and how to integrate the various elements of the WREN board. These examples have been included for your information, in the Basic Examples folder.

TCA6408A Driver

Rather than continue development of a TCA6408A component, I have taken a lambda approach and created code within the YAML , which drives the GPIO Expander. This makes is much easier - as a starting point, due to being self contained.

Required Editing

The code should work as it is but you will ideally need to update the footer ESPHome API details, which I have xxxx out.

Enable Home Assistant API

api:
  encryption:
    key: "xxxx="

ota:
  - platform: esphome
    password: "xxxx"

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Wren-C5-Test Fallback Hotspot"
    password: "xxxx"

Documentation - WREN-C5 Motor Controller Firmware Overview

Purpose

This firmware runs on the ESP32-C5 and provides control and monitoring for a dual-motor actuator system using a TCA6408A I²C GPIO expander and motor driver circuitry.

The firmware performs:

• Dual motor direction control

• Automatic enable control of motor drivers

• Motor fault detection

• Supply voltage monitoring

• Temperature monitoring

• Fault indication using a TCA6408A LED output

• Automatic recovery via ESP restart

• Wi-Fi telemetry through ESPHome

Hardware Architecture

ESP32-C5

The ESP32-C5 is the main controller and performs:

• Input monitoring
• Motor control logic
• Fault detection
• I²C communications
• Sensor monitoring
• ESPHome integration

TCA6408A I/O Expander (I²C Address 0x21)

The TCA6408A provides eight output signals.

Output Mapping

Bit	Function
P0	EN1
P1	Motor 1 Extend
P2	Motor 1 Retract
P3	EN2
P4	Motor 2 Extend
P5	Motor 2 Retract
P6	Spare
P7	Status / Fault LED

The firmware configures all TCA6408A pins as outputs during boot.

Motor Control Logic

Motor Inputs

Motor 1

GPIO	Function
GPIO8	Motor 1 Extend
GPIO9	Motor 1 Retract

Motor 2

GPIO	Function
GPIO14	Motor 2 Extend
GPIO13	Motor 2 Retract

Enable Logic

The motor driver enable signals are always controlled together.

When any motor command is active:

• EN1 = HIGH
• EN2 = HIGH

When no motor command is active:

• EN1 = LOW
• EN2 = LOW

This ensures both motor driver channels are enabled and disabled simultaneously.

Direction Control

Motor 1

Input	Output
IN_1A	Motor 1 Extend
IN_1B	Motor 1 Retract

Motor 2

Input	Output
IN_2A	Motor 1 Extend
IN_2B	Motor 1 Retract

Outputs are updated continuously by the motor supervisor task.

Fault Detection

The firmware contains multiple layers of fault detection.

Motor Driver Fault (SFLAG)

Input

GPIO10

Behaviour

When SFLAG becomes active:

1. All TCA outputs immediately go LOW

2. EN1 goes LOW

3. EN2 goes LOW

4. All motor drive outputs go LOW

5. Fault state is latched

6. Fault LED flashes

7. ESP32 automatically restarts

Detection methods:

• GPIO interrupt (fastest)

• Supervisor polling backup

This provides rapid fault response even if an interrupt is missed.

Supply Voltage Protection

The ADC continuously monitors supply voltage.

Input

GPIO4

Limits

Condition	Action
Fault	<10 V or >48 V

Fault

On fault:

• Motor outputs disabled

• Fault LED flashes

• System restarts

Fault Indication

TCA6408A LED

Bit 7 of the TCA6408A is used as the fault LED indicator.

Normal Operation

LED OFF

Fault Condition

LED flashes repeatedly

Pattern:

• ON 100 ms

• OFF 100 ms

• Repeated 20 times

After flashing completes:

• ESP restart occurs

Heartbeat Indicator

ESP32 GPIO27 drives the onboard heartbeat LED.

Purpose:

• Visual indication firmware is running

• Visual indication scheduler is operating normally

Recommended pattern:

• ON 750 ms

• OFF 250 ms

Sensor Monitoring

TMP102 Temperature Sensor

I²C Address: 0x4A

Provides:

• Board temperature

• Thermal monitoring

• Home Assistant reporting

Supply Voltage

ADC input:

GPIO4

Voltage divider scaling:

44.4444

Provides:

• Input voltage monitoring

• Fault detection

• Telemetry

Wi-Fi RSSI

Reports wireless signal strength for diagnostics.

Uptime

Reports controller runtime.

Startup Sequence

1. ESP32 boots

2. TCA6408A initialized

3. All outputs forced LOW

4. TCA polarity register configured

5. TCA direction register configured

6. Fault state cleared

7. SFLAG checked

8. Normal operation begins

If SFLAG is already active during boot:

• Fault handler executes immediately

• Motors remain disabled

• LED flashes

• ESP restarts

Safety Features

The firmware implements several safety mechanisms:

Immediate Motor Shutdown

The following safety motor shutdown has been included in hardware.

• Over current protection
  • Either motor port become overloaded
• Cross Conduction of control wiring
• Thermal Shutdown
• Under/Over Voltage

These events trigger the ENx line to force low. If the either motor is running at the time, this will immediately force a fault.

Any detected fault immediately writes:

Output Register = 0x00

This disables:

• EN1

• EN2

• Motor 1 outputs

• Motor 2 outputs

Fault Latching

Once a fault occurs:

• fault_active = true

• Motor outputs remain disabled until restart.

Automatic Recovery

After fault indication:

• esp_restart()

• is executed to restore the system to a known state.

Timing Parameters

Function	Interval
Heartbeat LED	1 second
Motor Supervisor	10 ms
ADC Voltage Update	30 seconds
Motor	1 second
TMP102 Update	30 seconds
Wi-Fi RSSI	60 seconds

Summary

The WREN-C5 firmware provides a robust dual-motor control platform with:

• Dual motor direction control

• Shared driver enable control

• Immediate fault shutdown

• Voltage protection

• Thermal monitoring

• Fault LED indication

• Automatic recovery

• ESPHome integration

• I²C-based output expansion

The design prioritizes safe motor shutdown and automatic recovery while maintaining simple integration with Home Assistant and ESPHome.

Open Source

This test code is OPEN SOURCE and formatted for easier viewing. Although is is not intended for real world use, it may be freely used, or modified as needed. It is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

Further Information

Additional information, and other technical details on this project, maybe found in the related repository pages.

Repository Folders

• Code (Code examples for Arduino IDE, Raspberry Pi and PlatformIO)
• Datasheets and Information (Component Datasheets, Schematics, Board Layouts, Photos, Technical Documentation)
• Certification (Related Repository Project or Part, Certification Information)

Repository Tabs

• Wiki (Related Repository Wiki pages and Technical User Information)
• Discussions (Related Repository User Discussion Forum)
• Issues (Related Repository Technical Issues and Fixes)

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Dave Williams, Maidstone, UK.

Electronics Engineer | Software Developer | R&D Support | RF Engineering | Product Certification and Testing | STEM Ambassador

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