config and brief explanation in README

README.md

@@ -28,6 +28,57 @@ Features not yet implemented but planned:
 
 ![Alt](/.gitea/webview0.png "Web view demo")
 
+## Configuring the TH7
+
+This program is controlled with a config file `config.toml` in which the user can configure each thermocouple channel independently, enable a web view, configure database logging, etc.
+The TH7 software uses sane default values where possible.
+
+```properties
+# EXAMPLE TH7 CONFIG
+[TH7]
+# port used by the web view
+port = 9090
+# enable the blinking lights on the Raspberry Pi Hat
+LED = true
+# if true, the software will use a simulated TH7
+debug = false
+
+# Configure channel 1
+[Channel_1]
+# set type to K-type thermocouple
+type = 'K'
+# gain is used during signal conversion
+gain = 106.8
+# offset is added to the final converted value (in °C)
+offset = -5.6
+# samples for the filter function
+filter.samples = 50
+# integer representing the filter function type
+filter.type = 0
+
+# Filter functions:
+# 0: simple alpha-beta filter (default)
+# 1: lag filter: old * 0.90 + new * 0.10
+# 2: lag filter: old * 0.95 + new * 0.05
+# 3: lag filter: old * 0.99 + new * 0.01
+
+# Configure channel 2 to read μV
+# this example uses default values for gain, offset and filter.
+[Channel_2]
+# set thermocouple type to 'U' to just read μV
+type = 'U'
+
+# Database
+# Each database type (so far only SQLite3) requires its own set of values
+# Below is an example for SQLite3
+[DB]
+type = "sqlite3"
+# where to save the database file
+path = "/home/pi/th7.db"
+# logging frequency. specified in seconds.
+freq = 60
+```
+
 ## Building on a Raspberry Pi
 
 This code builds without fuss on Raspberry Pi 4 with go version go1.19.3 linux/arm

config.toml

@@ -2,6 +2,7 @@
 [TH7]
 port = 9090                     # web port
 debug = true                    # enable to use simulated PCB for development
+nolog = true
 
 # all DB settings are individual to each DB
 [DB]

config/config.go

@@ -51,12 +51,7 @@ func Load() (config.Config, error) {
 		return cfg, err
 	}
 
-	v.SetDefault("TH7.port", 8080)
-	v.SetDefault("TH7.cache", true)
-	v.SetDefault("TH7.LED", true)
-	v.SetDefault("TH7.debug", false)
-	v.SetDefault("TH7.nolog", false)
-	v.SetDefault("DB.freq", 60)
+	SetDefaultConfig(v)
 
 	cfg.Board.Port = v.GetInt("TH7.port")
 	cfg.Board.Cache = v.GetBool("TH7.cache")
@@ -67,18 +62,6 @@ func Load() (config.Config, error) {
 
 	cfg.Channels = make([]config.Channel, 0)
 
-	// set defaults for channels
-	for i := 1; i < 8; i++ {
-		var head = fmt.Sprintf("Channel_%d", i)
-		v.SetDefault(head+".type", "NOTSET")
-		v.SetDefault(head+".gain", 106.8)
-		v.SetDefault(head+".offset", 0.0)
-		v.SetDefault(head+".unit", "UV")
-		// filter settings
-		v.SetDefault(head+".filter.samples", 50)
-		v.SetDefault(head+".filter.type", 0)
-	}
-
 	for i := 1; i < 8; i++ {
 		var c config.Channel
 		var tc thermocouple.Type
@@ -97,8 +80,8 @@ func Load() (config.Config, error) {
 			fmt.Printf("%s.type=%s\n", head, v.GetString(head+ ".type"))
 			return cfg, err
 		}
-		c.Thermo = tc
 
+		c.Thermo = tc
 		c.Filter.SampleSize = v.GetInt(head + ".filter.samples")
 		c.Filter.Type = v.GetInt(head + ".filter.type")
 

config/defaults.go

@@ -0,0 +1,28 @@
+package config
+
+import (
+	"fmt"
+
+	"github.com/spf13/viper"
+)
+
+func SetDefaultConfig(v *viper.Viper) {
+	v.SetDefault("TH7.port", 8080)
+	v.SetDefault("TH7.cache", true)
+	v.SetDefault("TH7.LED", true)
+	v.SetDefault("TH7.debug", false)
+	v.SetDefault("TH7.nolog", false)
+	v.SetDefault("DB.freq", 600)
+
+	// set defaults for channels
+	for i := 1; i < 8; i++ {
+		var head = fmt.Sprintf("Channel_%d", i)
+		v.SetDefault(head+".type", "NOTSET")
+		v.SetDefault(head+".gain", 106.8)
+		v.SetDefault(head+".offset", 0.0)
+		v.SetDefault(head+".unit", "U")
+		// filter settings
+		v.SetDefault(head+".filter.samples", 50)
+		v.SetDefault(head+".filter.type", 0)
+	}
+}