From 4612a4c87c4ea19f09042928dff338aab68c98a1 Mon Sep 17 00:00:00 2001
From: Erich Eckner <git@eckner.net>
Date: Mon, 23 Sep 2019 12:00:02 +0200
Subject: interpoliere fertig

---
 interpoliere | 120 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100755 interpoliere

diff --git a/interpoliere b/interpoliere
new file mode 100755
index 0000000..d731a95
--- /dev/null
+++ b/interpoliere
@@ -0,0 +1,120 @@
+#!/bin/bash
+
+finde_interpolierten_wert() {
+  local t="$1"
+  local lv='0'
+  local lt='-273.15'
+  sed '
+    /^\s*#/d
+    s/ -$//
+    t
+    s/ \S\+ / /
+  ' "${0%/*}/werte" \
+  | if [ "x$2" = 'xinvers' ]; then
+    sed '
+      s/^\(\S\+\) \(\S\+\)$/\2 \1/
+    '
+  else
+    cat
+  fi \
+  | while read -r ct cv; do
+    if printf '(%s)-(%s)\n' "${ct}" "${t}" \
+    | bc -l \
+    | grep -q '^[^-]'; then
+      printf '((%s)-(%s))/((%s)-(%s))*((%s)-(%s))+(%s)\n' \
+        "${t}" "${lt}" \
+        "${ct}" "${lt}" \
+        "${cv}" "${lv}" \
+        "${lv}" \
+      | bc -l
+      break
+    fi
+    lt="${ct}"
+    lv="${cv}"
+  done
+}
+
+gib_absolute_luftfeuchte() {
+  printf '(%s)*(%s)/100\n' \
+    "$(finde_interpolierten_wert "$1")" \
+    "$2" \
+  | bc -l
+}
+
+fh=$(
+  curl -Ss 'http://wetter.mb.fh-jena.de/station/datenbank/php_giese/online.php'
+)
+fh_t=$(
+  printf '%s\n' "${fh}" \
+  | sed '
+    \@>Temperatur</td>@ {
+      N
+      s@^.*<strong>\(\S\+ \)@\1@
+      t
+    }
+    d
+  ' \
+  | awk '{print $1}'
+)
+fh_rh=$(
+  printf '%s\n' "${fh}" \
+  | sed '
+    \@>Luftfeuchtigkeit</td>@ {
+      N
+      s@^.*<strong>\(\S\+\) %</strong></td>\s*$@\1@
+      t
+    }
+    d
+  '
+)
+
+fh_ah=$(
+  gib_absolute_luftfeuchte "${fh_t}" "${fh_rh}"
+)
+fh_tp=$(
+  finde_interpolierten_wert "${fh_ah}" invers
+)
+
+kpi=$(
+  curl -Ss 'https://kpi.ddns.eckner.net/tmp/sensor'
+)
+kpi_rh=$(
+  printf '%s\n' "${kpi}" \
+  | sed '
+    s/^RH: \(\S\+\) %$/\1/
+    t
+    d
+  '
+)
+kpi_t=$(
+  printf '%s\n' "${kpi}" \
+  | sed '
+    s/^T: \(\S\+\) °C$/\1/
+    t
+    d
+  '
+)
+
+kpi_ah=$(
+  gib_absolute_luftfeuchte "${kpi_t}" "${kpi_rh}"
+)
+kpi_tp=$(
+  finde_interpolierten_wert "${kpi_ah}" invers
+)
+
+ah_anteil=$(
+  printf '(%s)/(%s)*100\n' "${kpi_ah}" "${fh_ah}" \
+  | bc -l
+)
+kpi_tp_diff=$(
+  printf '(%s)-(%s)\n' "${kpi_t}" "${kpi_tp}" \
+  | bc -l
+)
+fh_tp_diff=$(
+  printf '(%s)-(%s)\n' "${kpi_t}" "${fh_tp}" \
+  | bc -l
+)
+
+printf '%s %% so viel Wasser innen wie außen\n' "${ah_anteil}"
+printf '%s K über innerem Taupunkt\n' "${kpi_tp_diff}"
+printf '%s K über äußerem Taupunkt\n' "${fh_tp_diff}"
-- 
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