Stevenson Screen for DHT22/MPL3115A2 with Pie Tins by rlgjr562

Last crawled date: 3 years, 1 month ago

Updated the probe for the DHT22 / MPL3115A2, the holes coming up through the base were enlarged and sensor mounting areas were tinkered with after my first print showed some issues. The DHT22 / MPL3115A2 probe was made with Tinkercad. Edit it online if you need any tweaking for your sensors. https://www.tinkercad.com/things/2neqPEmkfyT
This is a project that marries 3d printed Items (Base and Mount) with already available items (Pie Tins) to create a Stevenson Screen. To a purist, since all the pieces can be printed they should be. I do not have a 3d Printer yet, so to lower costs I used some readily available ready made items, the pie tins lower the over cost of the project.
I initially started searching for a 3d project and found several suitable candidates, but the cost was to high. So I search for a way to lower the cost and found two:

a Paper by the USDA - Forestry service titled "An inexpensive meteorological radiation shield for thermistors and thermocouples" it is available on many sites including: https://archive.org/details/inexpensivemeteo190barn

A website called "Weather for Schools" it is a UK site that discusses how to use Plant Pot saucers as the Stevenson shield for for the Temperature and Humidity measurement.http://www.weatherforschools.me.uk/docs/weather_box_sensor.pdf
I selected pieces of several remixes to work in tandem with the pie tins or plant saucers.
I Used the following Electronic and off the shelf pieces for this project:
Adafruit Feather M0 WiFi - ATSAMD21 + ATWINC1500https://www.adafruit.com/product/3061 - uses external Antenna
Also available with a built in antenna - https://www.adafruit.com/product/3010
Terminal Block Breakout FeatherWing (The larger half size prototype board could be used)https://www.adafruit.com/product/2926
USB / DC / Solar Lithium Ion/Polymer charger - v2https://www.adafruit.com/product/390
Blocking Diode
I used a Schottky Diode10SQ045
Medium 6V 2W Solar panel - 2.0 Watthttps://www.adafruit.com/product/200
Small Solar Panel Brackethttps://www.voltaicsystems.com/small-bracket
Solar Extension with Exposed Leads to go into the electronics boxhttps://www.voltaicsystems.com/extension-with-exposed-leads
Battery - Lithium Ion Polymer Battery - 3.7v 2500mAhhttps://www.adafruit.com/product/328
Thermistor to measure temp of batteryhttps://www.adafruit.com/product/372
3k 1/4w Resistor to limit current draw based on 6V 2W Solar panelhttps://www.jameco.com/z/CF1-4W302JRC-3k-Ohm-1-4-Watt-Carbon-Film-Resistor_690970.html
Barometric Pressure & Altitude Sensor MPL3115A2https://www.adafruit.com/product/1893
Temperature / Humidity Sensor DH22https://www.adafruit.com/product/385
5" Steel Pie Tins or 6" Plastic Flower Pot saucers
M/F pair 4 wire Black Pigtail Plastics Waterproof IP65 cable assembles. There are other brands but I used some from.https://www.adafruit.com/product/744
orhttps://www.amazon.com/gp/product/B01EPN9Y2W/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1
Small Waterproof Nylon Cable Glands PG7 / M12 size suitable for wire 3mm-6.5mm Diahttps://www.adafruit.com/product/762
orhttps://www.amazon.com/gp/product/B01MQWU4QW/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1
Waterproof box to house the electronics. The one I used was 125mm x 175mm x 75mm
There are several on Thingiverse that can be printed.https://www.thingiverse.com/thing:1680291
or I choose to purchase onehttps://www.adafruit.com/product/905
Arcylic sheet (for mounting the circuit boards) Available in hardware stores, Lowes, Home Depot, Etc...
M2.5 or M3 x 6mm Standoffs I found these on Amazon
M2.5 or M3 x 5mm Screws I found these on Amazon
pole 1" (Bird feeder pole) to 1 3/4 (TV anntenna Mast) to mount the Stevenson Shield, the electronic enclosure, and Sloar panel
U Bolts or clamps sized for the pole. Available in hardware stores, Lowes, Home Depot, Etc...
Follow On project: https://www.thingiverse.com/thing:3529776 This allows the SparkFun & Misol Wind Speed, Wind Direction and Rain Fall Measurement to talk to a Master Station via I2C.