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oak:tutorials:weather

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Weather Shield Kit Tutorial

Product Description:

weather0.jpg

The Weather Shield Kit includes the circuit board, resistors, an SHT21 precision temperature and humidity module, a BMP180 precision barometric pressure module, a photocell (for measuring ambient light), and an I2C ADC chip to provide additional ADC pins for the shield to use! In addition it comes with two RJ11 jacks that are compatible with most wired Wind vane, anemometer, and rain gauges.

This is an unassembled kit and requires basic soldering. This is designed for use with the Oak development board, which is not included.

Parts:

Part Quantity Identification
Weather Shield PCB 1
Small diode 6 1N4148
1K ohm 1/4 W resistor 5% 6 Brown - Black - Red
4.7K ohm 1/4 W resistor 5% 3 Yellow - Violet - Red (4K7)
10K ohm 1/4 W resistor 5% 1 Brown - Black - Orange
Light-dependant resistor 1 LDR
Temperature & Humidity sensor 1 SHT21
Barometric pressure sensor 1 BMP180
I2C ADC chip 1 PCF8591P
16-pin IC socket 1
RJ11 (“telephone”) jacks 2
1×40 pin male 0.1“ pitch header 17+ pins worth

Resistor Values: For more information on how to identify the value of the resistors, we recommend these sites: A nice simple resistor calculator: http://www.ealnet.com/m-eal/resistor/resistor.htm A comprehensive article on identification: http://www.diyaudioandvideo.com/Electronics/Color/

Personally, I found the key was identifying with the colors rather than the words. After short-term-memorizing the basic color-to-number map (Big(0) Boys(1) Race(2) Our(3) Young(4) Girls(5) But(6) Violet(7) Generally(8) Wins(9)), I spent a few days muttering the right number to myself for everything I looked at in everyday life; black pen - “0”, brown wood - “1”, red sweater - “2”…white car - “9”. After linking color with the numbers enough, I can just read resistors as if the numbers were printed on them.

Soldering: If you are new to soldering we recommend the following tutorials: Soldering Basics (http://www.sparkfun.com/tutorials/106) and Soldering Crash Course from the folks at Sparkfun (http://www.sparkfun.com/tutorials/354). How to solder from the Curious Inventor: http://store.curiousinventor.com/guides/How_to_Solder

Adafruit has this excellent guide that starts with the tools needed and then shows detailed pictures, including some of the common problems that beginners experience (http://learn.adafruit.com/adafruit-guide-excellent-soldering)

We assume for these assembly instructions that you know the basics of thru-hole soldering. If you check out the links above, these boards are very easy to solder - we promise! This board does has a fair number of parts to solder. We recommend that you take the time to go through the instructions at least once before starting. Do not rush the assembly. Be sure when placing a part that it is the correct part for the location and in the correct orientation with respect the PCB top, bottom, and required placement before soldering.

Assembly:

Empty kit bag (or if using a raw PCB, acquire parts), verify contents, and organize the parts, especially small ones.

weather1.jpg

Resistors can be installed in either direction, but the diodes need to have the black band at one end match the printed stripe; conveniently they all go the same way, with the band near the sensor modules.

weather2.jpg

I like to build in stages working from groups of small, numerous, components up to bulkier connectors. Here I first soldered in the diodes and then the 4K7 and 10K resistors, next up: the 1Ks

weather3.jpg

The socket for the A/D chip should have its notch match the outline on the board; when you add the chip later, it has a similar notch to show you which way it goes. The socket can be held in place for soldering by bending the corner pins out slightly.

weather4.jpg

Getting the sensor modules oriented correctly is a little tricky as the BMP108 has the pin labels on the bottom and the SHT21 labels them on the top. Here is a picture of them laid on the board correctly; this can also be confirmed by checking continuity with VCC and GND on the far side of the A/D socket. (Note: the pins labelled VIN on the modules connect with VCC on the board)

weather5.jpg

When soldering the sensor modules to their four-pin headers, I put the long side of the pins into a breadboard, set the module onto short side, and propped the sensor up with a bit of female header so I could solder it reasonably straight; I did the same when soldering to them to the board.

weather6.jpg

Finally I soldered on the RJ11 jacks, seated the A/D chip and added the downward-pointed headers.

weather7.jpg

Something's missing? Why, yes! Because I don't know where or how I'm going to mount it yet, I did not solder on the light-dependent resistor (LDR); like the other resistors, it can be connected either way, but wherever I put this I want it to measure general ambient light and not have any sources shine directly on the sensitive surface.

weather8.jpg

oak/tutorials/weather.1455989230.txt.gz · Last modified: 2016/02/20 09:27 by bjh