{"id":164,"date":"2015-05-21T23:20:00","date_gmt":"2015-05-21T13:20:00","guid":{"rendered":"http:\/\/stevoz.com\/myweatherblog\/?p=164"},"modified":"2015-05-29T21:28:10","modified_gmt":"2015-05-29T11:28:10","slug":"fun-with-the-arduino","status":"publish","type":"post","link":"https:\/\/stevoz.com\/myweatherblog\/2015\/05\/fun-with-the-arduino\/","title":{"rendered":"Fun with the Arduino"},"content":{"rendered":"

I have had my weather station reporting to my website via a Raspberry Pi for seventeen months now and I enjoyed tinkering with it over that time. In addition to the Raspberry Pi, I have seen references to the Arduino<\/a> which is a microcontroller and I’m intrigued by that as well. It looks very promising for setting up other sensors around the place that I can monitor. One project that comes to mind is monitoring the water level in my tank.<\/p>

The other day I bit the bullet and bought a Freetronics Experimenters Kit for Arduino<\/a>. The heart of the kit is the Freetronics Eleven<\/a> which is an Arduino Uno clone. I also grabbed a Humidity and Temperature Sensor Module (DHT22)<\/a> while I was there.<\/p>

I was playing with the arduino tonight and set up a simple circuit with the humidity and temperature sensor and a couple of LEDs. I also discovered the Fritzing<\/a> programme which enables me to draw a schematic of my circuit and show the breadboard layout. So much fun to be had!<\/p>

What you have to do is set up your circuit, connect it to your PC and then upload a sketch to it. The sketch is the code that you write to control the Arduino. This code is based on the C language.<\/p>

Anyway, for the sake of having a play, I thought a simple experiment I could do is measure the humidity and temperature, output the results to the screen and also set up a couple of LEDs so that if the temperature is greater or equal to 25°C, then a red LED lights but if the temperature falls below 25°C then a green LED lights.<\/p>

Here is my circuit:<\/p>

\"DHT22_bb\"<\/a><\/p>

\"DHT22_schem\"<\/a><\/p>

Here is the sketch which I put together based on some examples I found:<\/p>\n

\r\n#include "DHT.h"\r\n\r\n#define DHTPIN 2     \/\/ what pin we're connected to\r\n\r\n#define DHTTYPE DHT22   \/\/ DHT 22  (AM2302)\r\n\r\nDHT dht(DHTPIN, DHTTYPE);\r\n\r\nint redLed = 9;\r\nint greenLed = 11;\r\nfloat time;\r\n\r\nvoid setup() {\r\n  Serial.begin(9600);\r\n  Serial.println("DHT test");\r\n\r\n  dht.begin();\r\n  \r\n  pinMode(redLed, OUTPUT);\r\n  pinMode(greenLed, OUTPUT);  \r\n}\r\n\r\nvoid loop() {\r\n  \/\/ Reading temperature or humidity takes about 250 milliseconds!\r\n  \/\/ Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)\r\n  float h = dht.readHumidity();\r\n  float t = dht.readTemperature();\r\n\r\n  \/\/ check if returns are valid, if they are NaN (not a number) then something went wrong!\r\n  if (isnan(t) || isnan(h)) {\r\n    Serial.println("Failed to read from DHT");\r\n  } else {\r\n    Serial.print("Time: ");\r\n    time = millis()\/1000;\r\n    Serial.print(time);\r\n    Serial.print(" secs\\t");\r\n    Serial.print("Humidity: ");\r\n    Serial.print(h);\r\n    Serial.print(" %\\t");\r\n    Serial.print("Temperature: ");\r\n    Serial.print(t);\r\n    Serial.println(" *C");\r\n  }\r\n  \/\/ Turn red LED on and green LED off if the temperature is 25 degrees or more.\r\n  \/\/ Turn green LED on and red LED off if the temperature is less than 25 degrees.\r\n  if (t >= 25) {\r\n    digitalWrite(redLed, HIGH);\r\n    digitalWrite(greenLed, LOW);\r\n  }\r\n  else {\r\n    digitalWrite(redLed, LOW);\r\n    digitalWrite(greenLed, HIGH);\r\n  }\r\n  \/\/ Wait 5 seconds before starting the next reading.\r\n  delay(5000);\r\n}\r\n<\/pre>
And finally, the results as printed to the screen:
\n\"-dev-ttyACM0_005\"<\/a><\/p>
The water tank level indicator idea has been running through my head and I reckon I know how to do it. I have ordered a heap of parts from eBay so once they turn up I will get into it. Think ultrasonic sensor, solar powered transmitter, received by the Raspberry Pi, uploaded to a database and displayed on the web. I will be posting my progress (good or bad) on here so stay tuned… \ud83d\ude42<\/p>\n","protected":false},"excerpt":{"rendered":"
I have had my weather station reporting to my website via a Raspberry Pi for seventeen months now and I enjoyed tinkering with it over that time. In addition to the Raspberry Pi, I have seen references to the Arduino which is a microcontroller and I’m intrigued by that as […]<\/p>\n","protected":false},"author":1,"featured_media":166,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[],"class_list":["post-164","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/stevoz.com\/myweatherblog\/wp-content\/uploads\/sites\/2\/2015\/05\/dev-ttyACM0_005.png","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p5uBIO-2E","_links":{"self":[{"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/posts\/164","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/comments?post=164"}],"version-history":[{"count":2,"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/posts\/164\/revisions"}],"predecessor-version":[{"id":170,"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/posts\/164\/revisions\/170"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/media\/166"}],"wp:attachment":[{"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/media?parent=164"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/categories?post=164"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stevoz.com\/myweatherblog\/wp-json\/wp\/v2\/tags?post=164"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}