Dave Williams | DitroniX | G8PUO
9.2 KiB
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:
-
All TCA outputs immediately go LOW
-
EN1 goes LOW
-
EN2 goes LOW
-
All motor drive outputs go LOW
-
Fault state is latched
-
Fault LED flashes
-
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
-
ESP32 boots
-
TCA6408A initialized
-
All outputs forced LOW
-
TCA polarity register configured
-
TCA direction register configured
-
Fault state cleared
-
SFLAG checked
-
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
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
Voltage Update
1 second
TMP102 Update
10 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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