basic plant sensor interface

xylem/README.txt

@@ -0,0 +1,14 @@
+
+Basic plant sensor kit which currently outputs;
+ - soil humidity
+ - light levels
+ - human presence
+
+Hardware interface based loosly on recollection of Martin Howse's
+experiements with the Wheatstone Bridge[1] and incorporates parts of a
+design published by Rob Faludi[2] which in turn based on a design by
+Forrest Mims, with nods to L. Geroge Lawrence, Botanicalls and the
+long and tangled path from Jagdish Chandra Bose.
+
+[1] during piskel08
+[2] http://www.faludi.com/2006/11/02/moisture-sensor-circuit/

xylem/serial->pachube.scm

@@ -0,0 +1,55 @@
+
+;; interface to the pachube API 
+;;  http://community.pachube.com/?q=node/127
+;;  http://community.pachube.com/api
+
+
+;<?xml version="1.0" encoding="UTF-8"?>
+;<eeml xmlns="http://www.eeml.org/xsd/005">
+;  <environment>
+;    <data id="0">
+;      <value>36.2</value>
+;    </data>
+;  </environment>
+;</eeml>
+
+(module pachube scheme
+  
+  (require net/url)
+  
+  (provide (all-defined-out))
+  
+  (define source (string->url "http://www.pachube.com/api/1951.xml"))
+  (define api-key "")
+  
+  (define (format-data l m) (string-append "<?xml version='1.0' encoding='UTF-8'?><eeml xmlns='http://www.eeml.org/xsd/005'>
+<environment><data id='0'><value>" l "</value></data><data id='1'><value>" m "</value></data></environment></eeml>"))
+  
+  (define serial (open-input-file "/dev/cu.usbserial-A6004bp0"))
+  
+  (define (read-serial)
+    (process (read-line serial))
+    (read-serial))
+  
+  (define (process str)
+    (let ([data (regexp-split #rx"," str)])
+      (printf "light: ~a, moisture: ~a~n" (list-ref data 1) (list-ref data 2))
+      (send-data (list-ref data 1) (list-ref data 2))))
+  
+  ;; retrive data
+  ;; curl --request GET --header "X-PachubeApiKey: YOUR_API_KEY" "http://www.pachube.com/api/504.csv"
+  
+  (define (get-test)
+    (get-pure-port source (list (string-append "X-PachubeApiKey: " api-key))))
+  
+  ;; update the values from a feed
+  ;; curl --request PUT --header "X-PachubeApiKey: YOUR_API_KEY" --data "test" "http://www.pachube.com/api/504.csv"
+  
+  (define (send-data l m) 
+    (display-pure-port (put-impure-port 
+                        source 
+                        (string->bytes/utf-8 (format-data l m))
+                        (list (string-append "X-PachubeApiKey: " api-key)))))
+  
+  
+  )

xylem/xylem.pde

@@ -0,0 +1,48 @@
+// part of the groworld HPI prototype
+
+#include <stdio.h>
+ 
+#define lightpin 1  // light sensor on analog pin 1
+#define humidpin 0  // humidity sensor on analog pin 0
+#define power 8     // power for sensors
+
+unsigned long then = 0; // timer which will run for < 50 days
+unsigned long interval = 1; // interval between reads in seconds
+
+void setup()  
+{ 
+  pinMode(power, OUTPUT);
+  pinMode(humidpin, INPUT);
+  pinMode(lightpin, INPUT);
+
+  Serial.begin(9600); 
+}
+
+int lightlevel () 
+{
+  int light = 0;
+  light = (analogRead(lightpin)); 
+  return light; 
+}
+
+int moisturelevel () 
+{
+      int moist = 0;
+      digitalWrite(power, HIGH);
+      moist = (analogRead(humidpin)); 
+      digitalWrite(power, LOW);
+      return moist; 
+}
+
+char display[64];
+
+void loop() 
+{ 
+    if (millis() - then > interval*1000) {
+      then = millis(); 
+      sprintf(display, "%u,%u,%u\n", (unsigned int)then, lightlevel(), moisturelevel());
+      Serial.print(display);
+  }
+}
+
+