WeatherStation: slight update

 - Replaced the use of string.find by string.match, as it was not
   working as expected with the new lua interpretor.

 - Slight simplification of extract_value as we now can use a full-blown
   regular expression.

Change-Id: I1d7df66a272120cd10aa40f8e9326057b9709e3d

diff --git a/share/beaglebone/weather/weatherstation.lua b/share/beaglebone/weather/weatherstation.lua
old mode 100644 (file)
new mode 100755 (executable)
index f805391..8e287e6
--- a/share/beaglebone/weather/weatherstation.lua
+++ b/share/beaglebone/weather/weatherstation.lua
@@ -80,13 +80,14 @@ function read_file(filename)
 end
 
 -- Extract the value of the LABEL:VALUE pairs read from the device files.
-function extract_value(label, data, pat)
+function extract_value(data, pat)
 
-       local x, y, z = string.find(data, label .. "%s+: (" .. pat .. ")")
-       if x == nil or y == nil or z == nil then
+       local x = string.match(data, pat)
+
+       if x == nil then
                return "0"
        end
-       return z
+       return x
 end
 
 -- Read the sensor values and generate json output
@@ -97,20 +98,20 @@ function generate_json()
        if tsl2550 == nil then
                return nil
        end
-       local illuminance = extract_value("ILLUMINANCE", tsl2550, "%d+")
+       local illuminance = extract_value(tsl2550, "ILLUMINANCE: (%d+)")
 
        local sht21 = read_file("/dev/sht21b3s40")
        if sht21 == nil then
                return nil
        end
-       local temperature = extract_value("TEMPERATURE", sht21, "%d+.%d+")
-       local humidity = extract_value("HUMIDITY", sht21, "%d+.%d+")
+       local temperature = extract_value(sht21, "TEMPERATURE: (%d+.%d+)")
+       local humidity = extract_value(sht21, "HUMIDITY: (%d+.%d+)")
 
        local bmp085 = read_file("/dev/bmp085b3s77")
        if bmp085 == nil then
                return nil
        end
-       local pressure = extract_value("PRESSURE", bmp085, "%d+")
+       local pressure = extract_value(bmp085, "PRESSURE: (%d+)")
 
        json = json .. "{\n"
        json = json .. "\"temperature\": " .. temperature .. ",\n"