IO Card G3

IO-Card G3

This is my custom I/O card, third generation. Main purpose is to serve as an alarm system.

Hardware features

• 8 analog inputs for detecting changes in resistance (a.k.a balanced line).
• 8 digital inputs, 3.3-24V
• 8 digital outputs, 5/12V, fused.
• 6 controllable status LED.
• Optional BME280
• Wiegand interface
• On-board buzzer.
• SD Card (SPI and MMC bus selectable)
• JTAG debugging (when SD Card is using SPI)
• LED indicators for all input and outputs.
• Screw terminals for all interfaces.
• MCU: ESP32 Wrover Module
• Powered by 12V DC.

Software

• Web interface for configuration and status monitoring.
• MQTT for control and monitoring.

Software overview

Feature specification / task list

• NTP Based on config, synchronize clock with NTP server every 15 minutes.
• I2C
  • On interrupt on ANALOG_RDY_1 or ANALOG_RDY_2, read analog values; publish internally.
  • On interrupt on DIA_Interrupt, read digital input values; publish internally.
  • Periodically read BME280 values and publish internally (<id>/io/status/sensor)
  • Receive control events and set digital outputs accordingly.
    • Also handle SIREN_CTRL, even though it is not on the I2C bus.
• MQTT
  • All payloads must be JSON-formated.
  • Periodically publish all I/O statuses on the following topics:
    • <ID>/io/status/digital/input/<number>
    • <ID>/io/status/digital/output/<number>
    • <ID>/io/status/analog/input/<number>
    • <ID>/io/status/buzzer
    • <ID>/io/status/siren
    • Publish Wiegand button sequences on topic <ID>/io/status/wiegand
    • If enabled in configuration, allow I/O to be controlled via topic <ID>/io/set/channel_no, where channel_no is a number between 0 and 7.
  • All published items shall have a unix_timestamp value which tells when the item was created.
  • a value of true shall be interpreted as 'active', regardless if the input/output is active high or low. i.e. if the buzzer is making sounds, the the status is true.
  • All topics can be renamed via configuration.
    • The special string @ID@ is used to signify the ID of the device. Any instance of it in the replacement topic will be replaced with the device ID.
    • Once a topic is renamed, the original one ceases to function until the renaming is removed from the configuration.
• Wiegand
  • Listen to button presses and publish internally.
  • Each series must end with the execute_button button, usually '#' (but as its numerical button value). Any press on the cancel_button (*) clears any already entered numbers from the buffer.
  • If no input is received during entry_timeout milliseconds, the bufer is cleared and no number series is published.
• Alarm
  • Based on configuration, do:
    • Play sound using the buzzer when any armed I/O with an entry_delay larger than 0 changes state, for the duration of the delay.
    • Sound siren for X minutes when any input marked as armed no longer matches its configured armed_state. For analog inputs this means a value outside the range of value +/- allowed_hysteresis.
      • Delay for the configured entry_delay if the triggering input has one larger than 0. Immediately sound the siren if an input other than the first is triggered during the wait time.
    • Silence siren after X minutes, regardless if an IO marked as armed has returned to its armed_state or not.
      • Do not sound the siren again until after Y minutes.
    • Inputs with active set to false are never considered for any operation.

Startup procedure

• Initialize I2C Bus.
  • 2x MCP23017
  • 2x ADS1115IDGST
  • Optional BME280.
• Read SD_ENABLE to determine the mode for the SD Card.
  • Initialize SD Card.
    • If initialization fails, pause for a short amount of time and retry X times.
    • If initialization fails Y times, power cycle SD Card and try again.
• Read device ID from configuration.
  • If not set, generate a random number and set ID to IOG3_<number>.
• Start Wifi
• Start MQTT worker
• Start I2C worker
• Start Wiegand worker
• Start Alarm worker

Rendering of the PCB

(sorry, no 3D models for some components)

Configuration file examples

alarm.jsn

{
	"sensors":	{
		"digital":	{
			"input":	{
				"0":	{
					"name":	"D0",
					"enabled":	true,
					"armed_state":	true,
					"entry_delay":	5,
					"exit_delay":	5
				},
				"1":	{
					"name":	"1",
					"enabled":	false,
					"armed_state":	true,
					"entry_delay":	0,
					"exit_delay":	0
				},
				"2":	{
					"name":	"2",
					"enabled":	false,
					"armed_state":	true,
					"entry_delay":	0,
					"exit_delay":	0

dev_id.jsn

{
	"device_id":	"g3"
}

mqtt.jsn

{
	"keep_alive_seconds":	15,
	"broker":	{
		"address":	"1.2.3.4",
		"port":	1883
	}
}

notes.jsn

{
	"entry_delay": {
		"signal": [500, 500],
		"repeat": true
	},
	"exit_delay": {
		"signal": [1500, 500],
		"repeat": true
	},
	"error": {
		"signal": [250, 250, 250, 250, 250],
		"repeat": false
	},
	"armed": {
		"signal": [800, 200, 800, 200, 800],
		"repeat": false
	},
	"disarmed": {
		"signal": [800, 200, 800, 200],
		"repeat": false
	},
	"key_entry_timeout": {
		"signal": [200, 200, 200, 200, 200, 200],
		"repeat": false
	}
}

sntp.jsn

{
	"sntp_servers":	["0.se.pool.ntp.org", "1.se.pool.ntp.org", "2.se.pool.ntp.org"]
}

wifi.jsn

{
	"ssid":	"Your SSID",
	"password":	"Your password"
}