Gregory Ballantine
258 lines
7.9 KiB
Ruby
258 lines
7.9 KiB
Ruby
require 'i2c'
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require 'cyw43'
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require 'socket'
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# -------------------------------------------------------------
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# Configuration Loader
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# -------------------------------------------------------------
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begin
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require './config'
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rescue LoadError
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puts "ERROR: config.rb not found."
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puts "Create config.rb on the device with your Wi-Fi and MQTT credentials."
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loop { sleep 2 }
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end
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STATE_TOPIC = "homeassistant/sensor/#{Config::NODE_ID}/state"
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# -------------------------------------------------------------
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# Minimal MQTT 3.1.1 Client
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# -------------------------------------------------------------
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class SimpleMQTT
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def initialize(host, port = 1883)
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@host = host
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@port = port
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@sock = nil
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end
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def connect(client_id, username = nil, password = nil)
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@sock = TCPSocket.new(@host, @port)
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# Flags: Clean session (bit 1) + optional credentials
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flags = 0x02
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flags |= 0x80 if username
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flags |= 0x40 if password
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# Variable header: Protocol Name (MQTT) + Level (4) + Flags + KeepAlive (60s)
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var_header = [0x00, 0x04, 0x4D, 0x51, 0x54, 0x54, 0x04, flags, 0x00, 0x3C].pack('C*')
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# Payload
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payload = encode_str(client_id)
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payload << encode_str(username) if username
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payload << encode_str(password) if password
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body = var_header + payload
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packet = [0x10].pack('C') + encode_len(body.bytesize) + body
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@sock.write(packet)
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# Read CONNACK (4 bytes: 0x20, 0x02, ack_flags, return_code)
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resp = @sock.read(4)
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if resp.nil? || resp.getbyte(0) != 0x20 || resp.getbyte(3) != 0x00
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code = resp ? resp.getbyte(3) : 'nil'
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raise "MQTT connection failed: code #{code}"
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end
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end
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def publish(topic, payload, retain = false)
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cmd = 0x30 | (retain ? 0x01 : 0x00)
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body = encode_str(topic) + payload.to_s
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packet = [cmd].pack('C') + encode_len(body.bytesize) + body
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@sock.write(packet)
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end
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def disconnect
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@sock.write([0xE0, 0x00].pack('C*')) if @sock
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@sock.close if @sock
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rescue
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nil
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end
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private
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def encode_str(str)
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[str.bytesize].pack('n') + str
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end
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def encode_len(len)
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encoded = []
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loop do
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digit = len % 128
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len /= 128
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digit |= 0x80 if len > 0
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encoded << digit
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break if len == 0
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end
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encoded.pack('C*')
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end
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end
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# -------------------------------------------------------------
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# BME280 Driver (I2C)
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# -------------------------------------------------------------
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class BME280
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DEFAULT_ADDR = 0x76
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def initialize(i2c, addr = DEFAULT_ADDR)
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@i2c = i2c
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@addr = addr
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# Reset sensor
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@i2c.write(@addr, [0xE0, 0xB6].pack('C*'))
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sleep 0.1
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read_calibration_data
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# Humidity oversampling x1
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@i2c.write(@addr, [0xF2, 0x01].pack('C*'))
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# Pressure oversampling x1, Temp oversampling x1, Normal mode
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@i2c.write(@addr, [0xF4, 0x27].pack('C*'))
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# Standby 1000ms, filter off
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@i2c.write(@addr, [0xF5, 0xA0].pack('C*'))
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end
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def read_calibration_data
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calib = @i2c.read_from_mem(@addr, 0x88, 24)
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c = calib.unpack('S<s<s<S<s<s<S<s<s<')
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@dig_t1, @dig_t2, @dig_t3 = c[0], c[1], c[2]
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@dig_p1, @dig_p2, @dig_p3, @dig_p4, @dig_p5, @dig_p6 = c[3], c[4], c[5], c[6], c[7], c[8]
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@dig_h1 = @i2c.read_from_mem(@addr, 0xA1, 1).unpack1('C')
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h = @i2c.read_from_mem(@addr, 0xE1, 7).unpack('s<CBb<b<c')
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@dig_h2, @dig_h3 = h[0], h[1]
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e4 = @i2c.read_from_mem(@addr, 0xE4, 2).unpack('CC')
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@dig_h4 = (e4[0] << 4) | (e4[1] & 0x0F)
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@dig_h5 = (e4[1] >> 4) | (@i2c.read_from_mem(@addr, 0xE5, 1).unpack1('C') << 4)
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@dig_h6 = @i2c.read_from_mem(@addr, 0xE7, 1).unpack1('c')
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end
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def read_values
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raw = @i2c.read_from_mem(@addr, 0xF7, 8).unpack('C*')
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raw_p = ((raw[0] << 16) | (raw[1] << 8) | raw[2]) >> 4
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raw_t = ((raw[3] << 16) | (raw[4] << 8) | raw[5]) >> 4
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raw_h = (raw[6] << 8) | raw[7]
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# Temperature calculation (Celsius)
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var1 = (((raw_t >> 3) - (@dig_t1 << 1)) * @dig_t2) >> 11
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var2 = (((((raw_t >> 4) - @dig_t1) * ((raw_t >> 4) - @dig_t1)) >> 12) * @dig_t3) >> 14
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t_fine = var1 + var2
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temp = ((t_fine * 5 + 128) >> 8) / 100.0
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# Pressure calculation (hPa)
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p_var1 = t_fine - 128000
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p_var2 = p_var1 * p_var1 * @dig_p6 + ((p_var1 * @dig_p5) << 17) + (@dig_p4 << 35)
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p_var1 = ((p_var1 * p_var1 * @dig_p3) >> 8) + ((p_var1 * @dig_p2) << 12)
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p_var1 = (((1 << 47) + p_var1) * @dig_p1) >> 33
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pressure = if p_var1 == 0
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0
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else
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p = 1048576 - raw_p
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p = (((p << 31) - p_var2) * 3125) / p_var1
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p_var1 = (@dig_p9 * (p >> 13) * (p >> 13)) >> 25
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p_var2 = (@dig_p8 * p) >> 19
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((p + p_var1 + p_var2) >> 8) + (@dig_p7 << 4)
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(p / 256.0) / 100.0
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end
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# Humidity calculation (%)
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h_var = t_fine - 76800
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h_var = (((((raw_h << 14) - (@dig_h4 << 20) - (@dig_h5 * h_var)) + 16384) >> 15) *
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(((((((h_var * @dig_h6) >> 10) * (((h_var * @dig_h3) >> 11) + 32768)) >> 10) + 2097152) *
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@dig_h2 + 8192) >> 14))
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h_var = h_var - (((((h_var >> 15) * (h_var >> 15)) >> 7) * @dig_h1) >> 4)
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h_var = 0 if h_var < 0
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h_var = 419430400 if h_var > 419430400
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humidity = (h_var >> 12) / 1024.0
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{
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temperature: temp.round(2),
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pressure: pressure.round(2),
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humidity: humidity.round(2)
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}
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end
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end
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# -------------------------------------------------------------
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# Home Assistant MQTT Discovery
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# -------------------------------------------------------------
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def register_ha_discovery(mqtt)
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device_info = "\"device\":{\"identifiers\":[\"#{Config::NODE_ID}\"],\"name\":\"Pico 2W Weather\",\"model\":\"Pico 2 W\",\"manufacturer\":\"Raspberry Pi\"}"
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configs = [
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{
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id: "temperature",
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name: "Temperature",
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unit: "°C",
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cls: "temperature",
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val_tpl: "{{ value_json.temperature }}"
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},
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{
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id: "humidity",
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name: "Humidity",
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unit: "%",
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cls: "humidity",
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val_tpl: "{{ value_json.humidity }}"
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},
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{
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id: "pressure",
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name: "Pressure",
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unit: "hPa",
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cls: "atmospheric_pressure",
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val_tpl: "{{ value_json.pressure }}"
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}
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]
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configs.each do |c|
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topic = "homeassistant/sensor/#{Config::NODE_ID}/#{c[:id]}/config"
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payload = "{\"name\":\"#{c[:name]}\",\"state_topic\":\"#{STATE_TOPIC}\",\"unit_of_measurement\":\"#{c[:unit]}\",\"device_class\":\"#{c[:cls]}\",\"value_template\":\"#{c[:val_tpl]}\",\"unique_id\":\"#{Config::NODE_ID}_#{c[:id]}\",#{device_info}}"
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mqtt.publish(topic, payload, true)
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end
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end
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# -------------------------------------------------------------
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# Hardware & Network Init
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# -------------------------------------------------------------
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puts "Connecting to Wi-Fi..."
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CYW43.init
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CYW43.enable_sta_mode
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CYW43.connect_ap(Config::WIFI_SSID, Config::WIFI_PASS)
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while !CYW43.tcpip_link_status_up?
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sleep 1
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print "."
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end
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puts "\nConnected! IP: #{CYW43.ip_address}"
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# GP4 = SDA, GP5 = SCL
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i2c = I2C.new(unit: :RP2040_I2C0, sda_pin: 4, scl_pin: 5, frequency: 100_000)
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sensor = BME280.new(i2c)
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mqtt = SimpleMQTT.new(Config::MQTT_BROKER, Config::MQTT_PORT)
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puts "Connecting to MQTT broker at #{Config::MQTT_BROKER}..."
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mqtt.connect(Config::CLIENT_ID, Config::MQTT_USER, Config::MQTT_PASS)
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puts "Connected! Registering Home Assistant discovery..."
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register_ha_discovery(mqtt)
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# -------------------------------------------------------------
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# Main Loop
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# -------------------------------------------------------------
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loop do
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data = sensor.read_values
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puts "Temp: #{data[:temperature]} °C | Hum: #{data[:humidity]} % | Press: #{data[:pressure]} hPa"
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payload = "{\"temperature\":#{data[:temperature]},\"humidity\":#{data[:humidity]},\"pressure\":#{data[:pressure]}}"
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mqtt.publish(STATE_TOPIC, payload)
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sleep 30
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rescue => e
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puts "Error in telemetry loop: #{e.message}. Attempting reconnect..."
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sleep 5
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begin
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mqtt.disconnect
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mqtt.connect(Config::CLIENT_ID, Config::MQTT_USER, Config::MQTT_PASS)
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rescue
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nil
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end
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end
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