Initial commit of the server and hw code

.gitignore

@@ -3,3 +3,7 @@
 *.o
 *.so
 target/
+server/server
+server.key
+server.crt
+hw/esp8266/config.lua

hw/README.md

@@ -1,5 +1,5 @@
 # Hardware
 
-This directory will contain the code for programs running on the actual embedded
+This directory contains the code for programs running on the actual embedded
 hardware that reads data from the sensors and reports it to the Go server.
 

hw/esp8266/README.md

@@ -0,0 +1,7 @@
+# ESP8266
+
+This directory contains the code for reporting sensor data on the ESP8266
+platform running [NodeMCU][0].
+
+[0]: https://nodemcu.readthedocs.io/en/release/
+

hw/esp8266/config.example.lua

@@ -0,0 +1,57 @@
+-- Configuration file.
+--
+-- Change the settings and rename the file to config.lua, then upload it to the
+-- ESP8266 board to make things work.
+
+return {
+	--
+	-- Sensor identification.
+	--
+
+	-- Unique sensor name.
+	SENSOR_NAME = "test_sensor",
+
+	-- TLS certificate for sensor authentication.
+	-- TODO: CLIENT_CERT = [[]],
+
+	-- Sensor's private key.
+	-- TODO: CLIENT_PRIVATE_KEY = [[]],
+
+
+
+	--
+	-- Network setup.
+	--
+
+	-- SSID and password of the WiFi access point to connect to.
+	WIFI_SSID = "WIFI_SSID",
+	WIFI_PASS = "WIFI_PASS",
+
+	-- Address of the NTP server to use for time synchronization.
+	NTP_ADDR = "pool.ntp.org",
+
+	-- Address and port of our Go server.
+	SERVER_ADDR = "10.1.1.123",
+	SERVER_PORT = 42424,
+
+	-- TLS certificate of our Go server.
+	SERVER_CERT = [[
+ENTER CERTIFICATE HERE
+]],
+
+
+
+	--
+	-- Attached sensor configuration.
+	--
+
+	-- BME280 T/RH/p module connected to 3V3, G, D5 (SCL), D6 (SDA).
+	HAVE_BME280 = true,
+
+	-- MH-Z19B IR CO2 sensor (0-5000 ppm) connected to 5V (VU), G, D1 (PWM).
+	HAVE_CO2 = true,
+
+	-- BH1750 lux sensor module connected to 3V3, G, D7 (SCL), D2 (SDA).
+	HAVE_BH1750 = true
+}
+

hw/esp8266/init.lua

@@ -0,0 +1,277 @@
+-- NodeMCU firmware should include the following modules:
+--     bme280, cron, file, gpio, i2c, net, node, rtctime, sjson, sntp,
+--     tls, tmr, uart, wifi
+--
+-- To flash the firmware (do this just once):
+-- sudo esptool -p /dev/ttyUSB0 erase_flash
+-- sudo esptool -p /dev/ttyUSB0 write_flash 0x00000 nodemcu-release-14-modules-2022-07-14-12-14-56-integer.bin
+--
+-- To flash the code and config:
+-- sudo pip install -U --system nodemcu-uploader
+-- sudo nodemcu-uploader --port=/dev/ttyUSB0 upload config.lua
+-- sudo nodemcu-uploader --port=/dev/ttyUSB0 upload init.lua
+--
+-- To watch the debug output once the board is powered-on:
+-- screen /dev/ttyUSB0 115200
+
+local config = require("config")
+
+local SRV = nil
+local SRV_connected = false
+local SRV_reconnecting = false
+
+local CO2_ppm = 0
+local CO2_lo = 0
+local CO2_hi = 0
+local CO2_last_t = 0
+
+function CO2_int_handler(level, t)
+	if (level == gpio.LOW) then
+		CO2_hi = t - CO2_last_t
+	else
+		CO2_lo = t - CO2_last_t
+		CO2_ppm = (5000 * (CO2_hi - 2000)) / (CO2_hi + CO2_lo - 4000)
+	end
+	CO2_last_t = t
+end
+
+function sensor_setup()
+	if config.HAVE_BME280 then
+		-- BME280 module connected directly to 3V3, G, D5, D6.
+		local sda, scl = 6, 5
+		i2c.setup(0, sda, scl, i2c.SLOW)
+		local bm_type = bme280.setup()
+		-- The sensor is set up after about 120ms, but we don't need a delay here
+		-- because the first reading is done after the wifi finishes connecting,
+		-- which takes longer :)
+
+		if     bm_type == 1 then
+			print("[SENS] Detected BMP280 sensor (temperature, pressure).")
+		elseif bm_type == 2 then
+			print("[SENS] Detected BME280 sensor (temperature, pressure, humidity).")
+		else
+			print("[SENS] Detected neither BMP280 nor BME280!")
+			config.HAVE_BME280 = false
+		end
+	end
+
+	if config.HAVE_CO2 then
+		-- MH-Z19B IR CO2 sensor (0-5000 ppm) connected to 5V (VU), G, D1.
+		print("[SENS] Waiting for CO2 sensor to warm up...")
+		tmr.create():alarm(120000, tmr.ALARM_SINGLE,
+			function(t)
+				-- After the CO2 sensor has warmed up (3 min), start measuring PWM.
+				CO2_ppm = 0
+				CO2_lo = 0
+				CO2_hi = 0
+				CO2_last_t = tmr.now()
+				gpio.mode(1, gpio.INT)
+				gpio.trig(1, "both", CO2_int_handler)
+				print("[SENS] CO2 sensor warmed up.")
+			end)
+	end
+
+	if config.HAVE_BH1750 then
+		-- BH1750 lux sensor module connected to 3V3, G, D7 (SCL), D2 (SDA).
+		-- local sda, scl = 2, 7
+		-- i2c.setup(1, sda, scl, i2c.SLOW)
+
+		-- XXX: The firmware from NodeMCU-Builder seems to be built with the
+		-- old I2C implementation that only has 1 bus, so this breaks here
+		-- with error "i2c 1 does not exist", ugh.  There doesn't seem to be
+		-- any option to set it to use the new I2C implementation without
+		-- building it ourselves, so let's do an ugly workaround instead.
+
+		print("[SENS] BH1750 illuminance sensor configured.")
+	end
+end
+
+function sensor_report(_cron_entry)
+	-- Get the current timestamp.
+	local t_s, t_us, _clk_rate_offset = rtctime.get()
+
+	-- Get signal strength.
+	local rssi = wifi.sta.getrssi() -- dBm
+
+	-- Assemble sensor readings.
+	local data = {
+		name = config.SENSOR_NAME,
+		t = t_s,
+		RSSI = rssi
+	}
+
+	if config.HAVE_BME280 then
+		-- XXX: Kludge: Do the I2C setup again (see comment in sensor_setup).
+		local bme_sda, bme_scl = 6, 5
+		i2c.setup(0, bme_sda, bme_scl, i2c.SLOW)
+
+		local T, p, RH = bme280.read() -- C*100, hPa*1000, RH%*1000
+		data.T = T
+		data.p = p
+		data.RH = RH
+	end
+
+	if config.HAVE_CO2 then
+		-- Include CO2 reading only if the sensor has finished warming up.
+		if CO2_ppm > 0 then
+			data.CO2 = CO2_ppm
+		end
+	end
+
+	if config.HAVE_BH1750 then
+		-- XXX: Kludge: Do the I2C setup again (see comment in sensor_setup).
+		local bh_sda, bh_scl = 2, 7
+		i2c.setup(0, bh_sda, bh_scl, i2c.SLOW)
+
+		-- Read illuminance from BH1750 sensor at default address 0x23.
+		i2c.start(0)
+		i2c.address(0, 0x23, i2c.TRANSMITTER)
+		i2c.write(0, 0x10) -- Continuous high-res mode.
+		i2c.stop(0)
+		i2c.start(0)
+		i2c.address(0, 0x23, i2c.RECEIVER)
+		tmr.delay(200)
+		local val = i2c.read(0, 2)
+		i2c.stop(0)
+
+		local lux = (val:byte(1) * 256 + val:byte(2)) * 1000 / 1200
+		data.Ev = lux
+	end
+
+	-- Encode readings into JSON, terminate with LF.
+	local json = sjson.encode(data)..string.char(10)
+
+	-- Print encoded JSON for debugging.
+	print(json)
+
+	-- Send readings to remote server over the pre-established TLS connection.
+	tls_send(json)
+end
+
+function wifi_connect(ssid, password)
+	wifi.setmode(wifi.STATION)
+	cfg = {}
+	cfg.ssid = ssid
+	cfg.pwd  = password
+	cfg.save = false
+	wifi.sta.config(cfg)
+	wifi.sta.connect()
+end
+
+function wifi_wait4ip(callback)
+	tmr.create():alarm(1000, tmr.ALARM_AUTO,
+		function(t)
+			if wifi.sta.getip() ~= nil then
+				t:unregister()
+				callback()
+			end
+		end)
+end
+
+function tls_connect()
+	SRV:connect(config.SERVER_PORT, config.SERVER_ADDR)
+end
+
+function tls_init()
+	-- Enable server certificate verification.
+	tls.cert.verify(config.SERVER_CERT)
+
+	-- Enable client authentication.
+	-- TODO: tls.cert.auth(config.CLIENT_CERT, config.CLIENT_PRIVATE_KEY)
+
+	-- Connect to the server.
+	SRV = tls.createConnection()
+	SRV:on("connection",
+		function(sock, c)
+			SRV_connected = true
+			SRV_reconnecting = false
+			print("[SERV] Connection to server established.")
+		end)
+	SRV:on("disconnection",
+		function(sock, c)
+			SRV_connected = false
+			SRV_reconnecting = true
+			print("[SERV] Connection to server lost, reconnecting...")
+
+			-- Reconnect after 5 to 10 seconds.
+			local fudge = node.random(0, 5000)
+			tmr.create():alarm(5000 + fudge, tmr.ALARM_SINGLE,
+				function(t)
+					tls_connect()
+				end)
+		end)
+	tls_connect()
+end
+
+function tls_send(data)
+	-- Only send if the connection was established.
+	if SRV_connected then
+		SRV:send(data)
+	elseif not SRV_reconnecting then
+		tls_connect()
+	end
+end
+
+function time_setup()
+	local sync_success =
+		function(sec, usec, serv, info)
+			local t = rtctime.epoch2cal(sec)
+			local correction
+
+			if     info["offset_s"]  ~= nil then
+				correction = string.format("Correction: %d s", info.offset_s)
+			elseif info["offset_us"] ~= nil then
+				correction = string.format("Correction: %d us", info.offset_us)
+			else
+				correction = "Correction: none"
+			end
+
+			print(string.format(
+				"[SNTP] Date: %04d-%02d-%02d  Time: %02d:%02d:%02d  RTT: %d us  %s",
+				t["year"], t["mon"], t["day"],
+				t["hour"], t["min"], t["sec"],
+				info.delay_us,
+				correction))
+		end
+
+	local sync_failure =
+		function(err_type, err_detail)
+			local err
+			if     err_type == 1 then
+				err = "DNS lookup failed: " .. err_detail
+			elseif err_type == 2 then
+				err = "Memory allocation failure"
+			elseif err_type == 3 then
+				err = "UDP send failed"
+			elseif err_type == 4 then
+				err = "Timeout, no NTP response received"
+			else
+				err = "Unknown error"
+			end
+			print(string.format("[SNTP] Sync failed: %s.", err))
+		end
+
+	sntp.sync(config.NTP_ADDR, sync_success, sync_failure, 1)
+end
+
+function after_wifi_connects()
+	local ip, nm, gw = wifi.sta.getip()
+	print(string.format(
+		"[WIFI] Connected.  My IP: %s  Netmask: %s  Gateway: %s",
+		ip, nm, gw))
+
+	-- Set-up NTP.
+	time_setup()
+
+	-- Establish a TLS connection to the server.
+	tls_init()
+
+	-- Read and report sensor data once per minute.
+	cron.schedule("* * * * *", sensor_report)
+end
+
+
+sensor_setup()
+wifi_connect(config.WIFI_SSID, config.WIFI_PASS)
+wifi_wait4ip(after_wifi_connects)
+

server/Makefile

@@ -0,0 +1,27 @@
+#!/usr/bin/env gmake
+#
+# Makefile for the Go server.
+#
+
+GO ?= go
+
+all: server.go
+	@echo "*** Building Go server..."
+	@$(GO) build server.go
+
+clean:
+	@echo "*** Cleaning up..."
+	@-rm -f server
+
+key:
+	@test -f server.key || (echo "*** Generating server private key..."; openssl ecparam -genkey -name secp256r1 -out server.key)
+	@test -f server.crt || (echo "*** Generating server certificate..."; openssl req -new -x509 -sha256 -key server.key -out server.crt -days 3650 -batch)
+
+clean-key:
+	@echo "*** Cleaning up server key and certificate..."
+	@-rm -f server.crt server.key
+
+fmt:
+	@echo "*** Formatting source files..."
+	@$(GO) fmt server.go
+

server/README.md

@@ -1,5 +1,5 @@
 # Server
 
-This directory will contain the code for the Go server that collects sensor data
+This directory contains the code for the Go server that collects sensor data
 from the sensors, batches it, and submits it to the Cipher smart contract.