{"id":5727,"date":"2019-08-27T04:34:42","date_gmt":"2019-08-27T04:34:42","guid":{"rendered":"https:\/\/max-drake.cc\/?p=5727"},"modified":"2019-08-30T03:49:01","modified_gmt":"2019-08-30T03:49:01","slug":"raspberry-pi-and-temperature-sensor-ds1820","status":"publish","type":"post","link":"https:\/\/max-drake.cc\/?p=5727","title":{"rendered":"Raspberry Pi and temp sensor DS18B20 part 1"},"content":{"rendered":"\n

I’ve been keen to do some temperature monitoring. This is IoT basics 101. I thought of a use case for my Beer Brewing. <\/p>\n\n\n\n

Jaycar had DS18B20 temperature sensors at $7.90$ NZ each. They are cheaper than the DH11 & DH22 which are more expensive as they do humidity as well.<\/p>\n\n\n\n

So I thought I’d start off with these units. So found a couple of tutorials online: <\/p>\n\n\n\n

Tutorial 1-Measuring Temperature with a Raspberry Pi Temperature Sensor (1-Wire) <\/a><\/strong>and <\/p>\n\n\n\n

Tutorial 2- DS18B20+ One Wire Digital Temperature Sensor and the Raspberry Pi<\/a><\/strong>. <\/p>\n\n\n\n

Tutorial 3- Temperature Sensor Project using DS18B20<\/a><\/strong>.<\/p>\n\n\n\n

The interactive RPi pinout for gpio<\/strong><\/a> is quite handy.<\/p>\n\n\n\n

I have since found the data sheet of the DS18B20<\/strong><\/a>. <\/p>\n\n\n\n

Part 1- Abject failure-breaking the temperature sensors<\/h2>\n\n\n\n
\"\"<\/figure>\n\n\n\n

To begin with I looked on YouTube but got confused with some of their setups and they were not using breadboards, or had LED screens which increased the complexity of the wiring. So I looked at the first tutorial and sort of looked at the breadboard\/wiring layout and followed that (but missed the black wire to GPIO 6, so when I came to look in the \/sys\/bus\/w1\/devices\/<\/strong><\/em> directory there were no files there. <\/p>\n\n\n\n

So I went on to tutorial 2 and tried to wire up to that one. I had all the wires but then started to reverse them and the temperature sensor started to get hot. I had 2 temp sensors and basically have moggerdored them both. I think I’ve burned them out. <\/p>\n\n\n\n

The 2nd tutorial at least used Live\/Ground and after reviewing the data sheet I can see NOW which pin should have gone where. <\/p>\n\n\n\n

So for the time being an expensive mistake. $16 NZ down the drain and nothing to show for it. <\/p>\n\n\n\n

I have ordered a multi sensor pack online to play with but that wont come for a few weeks, so I have time to dwell on being a bit less cavalier about the wiring. <\/p>\n\n\n\n

Things to think about: <\/p>\n\n\n\n

  • See if I can understand the wiring diagram first in relation to the sensors before buggering them up. <\/li>
  • Do some testing with the breadboard or get thicker wires. Some of the wiring seemed very loose so I thought that there was not a circuit. <\/li>
  • Maybe get some LED’s to put in part of the circuit to check that the connections do work. <\/li>
  • Try tutorial 3 above. This one does not use breadboard but will be the final wiring for the sensors. Its also good for 2 or more sensors. So may be worth pursuing. <\/li><\/ul>\n\n\n\n

    Now I have to wait for some more sensors and proceed more slowly<\/h2>\n\n\n\n

    Maybe I was over confident with proceeding, although I did turn the Pi off while I did the first wiring up. I had such easy success with the camera module. Now I’m $16NZ poorer and no further ahead.<\/p>\n\n\n\n

    New sensors Friday 30th August<\/h3>\n\n\n\n

    I bought a couple of DS18B20 online from a NZ outlet, they looked quite reasonable, they were the bare bones temperature sensor, a black blob with 3 wires sticking out, but I got done on delivery prices, so in the end not much less than what I could have got in Jaycar, these ones were about $6.50 with out the board and LED light. Ce la vie.<\/p>\n\n\n\n

    I ended up wiring the first one up wrong AGAIN. I seem to be dyslexic with the pins for some reason, anyway, if it gets hot and smells, its the wrong way around. <\/p>\n\n\n\n

    This time it created a sub-directory after adding the extra line in the config.txt file but it did not initially have the sensor directory. So that took a few re-boots to get those to work, but I finally got there. <\/p>\n\n\n\n

    I finally used a bit of a sticker to mark the Ground prong from the thermometer sensor and things went fine after that. <\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n

    I now have 2 sensors working in parallel sending results to files w1_slave in the specific sensor directory. <\/p>\n\n\n\n

    \"\"
    2 sensors- I’m using a sticker to make sure I know which one is Ground. <\/figcaption><\/figure>\n\n\n\n

    End comment<\/h3>\n\n\n\n

    That took a lot of breakages to get a couple of temperature sensors working. I can only get their output by interrogating the file, so it is a live temp. It is not saving any data anywhere at this point. <\/p>\n\n\n\n

    The next part of the process is to explore methods to log the data over time, say, take a reading every minute\/5 minutes etc and store that data somewhere. <\/p>\n\n\n\n

    Also to send the data to another computer using MQTT or something similar. Initially I might use the cloud to act as a broker, then later install the broker on the RPi. <\/p>\n\n\n\n

    Overall a success for the first step, but it was not as simple as I thought. Lessons learnt? <\/strong>Be very careful about pins on sensors & wiring things up. <\/p>\n","protected":false},"excerpt":{"rendered":"

    I’ve been keen to do some temperature monitoring. This is IoT basics 101. I thought of a use case for my Beer Brewing. Jaycar had DS18B20 temperature sensors at $7.90$ NZ each. They are cheaper than the DH11 & DH22 which are more expensive as they do humidity as well. So I thought I’d start […]<\/p>\n","protected":false},"author":1,"featured_media":5728,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[204,443],"tags":[],"class_list":["post-5727","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-automation","category-iot-internet-of-things"],"featured_image_src":"https:\/\/max-drake.cc\/wp-content\/uploads\/2019\/08\/IMG_20190827_161632_resized_20190827_041918673.jpg","featured_image_src_square":"https:\/\/max-drake.cc\/wp-content\/uploads\/2019\/08\/IMG_20190827_161632_resized_20190827_041918673.jpg","author_info":{"display_name":"Max Drake","author_link":"https:\/\/max-drake.cc\/?author=1"},"_links":{"self":[{"href":"https:\/\/max-drake.cc\/index.php?rest_route=\/wp\/v2\/posts\/5727","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/max-drake.cc\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/max-drake.cc\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/max-drake.cc\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/max-drake.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5727"}],"version-history":[{"count":0,"href":"https:\/\/max-drake.cc\/index.php?rest_route=\/wp\/v2\/posts\/5727\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/max-drake.cc\/index.php?rest_route=\/wp\/v2\/media\/5728"}],"wp:attachment":[{"href":"https:\/\/max-drake.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5727"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/max-drake.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5727"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/max-drake.cc\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5727"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}