Saturday, July 7, 2012

DIY remote temperature Logger - Bits and Pieces

Ever since my weather station console fell off the computer table and broke the LCD, I have wanted to DIY a replacement.  Since we have the heat wave - I am inspired again.
Goal -

  • Outside arduino battery (solar?) radio sender
  • Inside Arduino console - linked to a site that graphs the data
Plan -

  • Document each sub system in separate Blog posts.

This post outlines the Hardware I accumulated for this project.

You will notice that I have a lot of different breakout board modules - For the first go round it is always better, for me, to have an already built module that has been debugged, than to start from scratch.  It might be cheaper to start with all the parts and build it out, but it certainly takes a lot more time. After it all works, I might, and that is a remote might, build a custom board.  But it is highly unlikely.

3.7V/670mAh Rechargeable Lithium-Ion
The battery was a close out - had internal protection circuitry and 650mah - more than enough to drive a sleepy Arduino for a long time,

Lithium rechargeable batterys are dangerious to charge - so I found this on eBay  A bit pricey but it suited me.  It's default charge current was a healthy one amp so I had to replarce the current set resistor to limit the current to ~35% of C for the battery (~4.7K for 350ma).   Little tiny surface mount resistors are out of the question for someone with my eyes. I used a 1/8w resistor on one and a trimmer pot on the other.

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NRF24L01 radio  They are all over eBay for all prices - I got mine from Digole Digital Solution in Canada and they arrived in just a few days.  I have done business with them in the past and liked them.  The Library I found to work the best for this board on the Arduino is the Maniacbug RF24

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Serial Display Adapter - I had a 16X2 display and never managed to include it into any project - simply because it took too many pins and too much code. Since I was on  Digole - got a couple.  A little disappointed that it did not include a command to turn the back light on and off - but that was a very minor point.

Diavilino - My favorite Arduino clone.  The Evil Mad Scientist basic kit costs around  around  $12 -  The biggest plus is that they take all the shields. I have a BUNCH of them.
 I never included the voltage regulator on any board - have always run them from batteries. Mostly 3 AA's. But for this project I thought I would need the Li-Ion - just because I wanted too.  They run @ 16mhz just fine on batteries.

DHT22  temperature-humidity sensor + extras

DHT22 temperature-humidity sensor From Adafruit  Something I had from a while back.

Proto Shield from Adafruit   Eventually when I get enough time, everything will be soldered onto one of these. I can and have created custom circuit boards in the past - but for one offs - nothing beats prototyping with  this shield - usually with a mini solderless breadboard on top. The after all the kinks are worked out - solder it down and call it done.