This week we continued working on our environmental gas sensor project. Our goals were to add solar power to the device and move the electronics into a weatherproof enclosure as we prepare for long-term data collection.
- Voltaic 6 watt, 6 volt solar panel, $59
- Adafruit Universal USB / DC / Solar Lithium Ion/Polymer charger, $14.95
- Seahorse Model SE120 enclosure ($20)
The first step was designing mounting plates for the electronics that will go into the enclosure. We used FreeCAD to make these designs which are on our Github site here. We designed two plates connected by standoffs. The TOP plate has a cutout for mounting the PyGamer and room for inserting/removing the SD card and accessing the on/off switch; the BOTTOM plate has mount holes for the battery, solar charger, GPS and BME688 environmental sensor.
The material used was 1/8" (3mm) thick black acrylic. The acrylic was cut on a laser cutter and the two plates are connected with 2" standoffs. Standoffs, screws and zip ties were used to mount the battery and electronics to the top and bottom plates as shown below.
The final assembled version is then inserted into the SE120 enclosure and secured with screws into threaded inserts which we added to the enclosure. Two small holes were drilled in the bottom of the enclosure for gas exchange and for the cable connecting to the solar panel. The enclosure was then mounted onto a piece of extruded aluminum (1010 80/20). A threaded rod was attached for inserting the unit into the ground. The solar panel was attached to the top of the 80/20 with a bracket. See pictures below for the final assembled unit.
Total unit cost so far:
The total cost of the unit is around $250 as detailed in the table below. We can easily add more sensors in the future.