BTT belter

README.md

@@ -2,6 +2,9 @@
 
 My collection of useful shell scripts.
 
+### belter_tension_calculator.sh
+script to calculate the tension with the readings from [BigTreeTech belter tool](https://bttwiki.com/belter.html) in mm, formula from the xlsx on their [git](https://github.com/bigtreetech/Belter-belt-tension-Tool).
+
 ### randint.sh 
 usage: randint \<positive integer\>   
 print in the terminal a random integer x with $` 0 \leq x \leq \$1`$

belter_tension_calculator.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+if ! [[ "$1" =~ ^-?[0-9](\.[0-9]+)?+$ ]]; then
+    echo "Usage: $0 <Belter display value (mm)>"
+    exit 1
+fi
+
+echo "Belter display value: $1mm"
+
+tension=$(awk -v x="$1" 'BEGIN {
+    if (x < 0) x = -x
+    printf "%.3f", 7.673640167 * x - 33.7167364
+}')
+
+echo "Belt tension: $tension N"
+echo ""
+
+ESC=$'\033'
+GREEN="${ESC}[32m"
+RED="${ESC}[31m"
+RESET="${ESC}[0m"
+
+check_range() {
+    local label="$1"
+    local min="$2"
+    local max="$3"
+
+    awk -v t="$tension" -v min="$min" -v max="$max" \
+        -v label="$label" -v G="$GREEN" -v R="$RED" -v Z="$RESET" '
+    BEGIN {
+        if (t >= min && t <= max)
+            printf "%s 🟩  %s[%.1f, %.1f] N%s\n", label, G, min, max, Z
+        else
+            printf "%s 🟥  %s[%.1f, %.1f] N%s\n", label, R, min, max, Z
+    }'
+}
+
+echo "Reference tensions:"
+check_range "Voron A/B belts    :" 7.8 15
+check_range "Voron 2.4 Z belts  :" 20.4 25.8
+check_range "V350/250 belts     :" 12 20
+check_range "GT2 belts          :" 20 30
+