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@shicks
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It’s not mentioned above, but equally important to surviving the cold weather and reduction in sunlight is to increase the capacity of the LiPo battery being charged by the panel. Depending on the type of sensors used and their current draw, a smaller battery might have trouble making it through a long stormy winter week, no matter what size panel is connected to it. So I recommend increasing the battery capacity to as large as you can comfortably get in your enclosure.
In our loggers, I use 2000mAh batteries in sunny spots, a 4400mAh battery in shady spots, and a 6600mAh battery in really problematic areas. This, combined with the larger panel, and reducing the transmit rate of the radio/cell module (this is the biggest power hog) should get you though anything.
And to answer the question above, the Voltaic Systems panels come with a small barrel-type connector. If you want to use those panels with a Mayfly, you’ll need to connect it to the JST header on the Mayfly, by either cutting and splicing your own homemade cable to the panel, or by ordering one of their barrel-socket-to-bare-lead cables, available on their website.
Good find! It’s only the printing on the PC board that is backwards — the actual pin traces follow the standard Grove I2C Pinout: SCL-SDA-Vcc-Gnd (as shown on the schematic). So this shouldn’t be a problem for anyone using a standard Grove cable with connectors on both ends, but if you use one with flying leads or are hacking together your own cable, then the misprint could cause some confusion. I’ll be sure to update the v0.3 and v0.4 board documentation to include a note about the misprint. Thanks!
The kits are still in stock, and the single boards should be in stock later this week. More were sent to Amazon last week but their inventory processing has been slowed because of the holidays.
You are correct, the 5v boost circuit on the Mayfly v0.4 has a max current supply of 200ma.
The sleeping sketch I mentioned above works fine as long as you don’t use the SDI12 library at the same time. If you do, there’s some conflicts due to the SDI12 and SODAQ_Pcint libraries looking at the same ports. So I created modified versions of both libraries that fixes the conflict. (This conflict also happens if you use SoftwareSerial and Pcint at the same time, so I also made a modified version of SoftwareSerial.) It’s kind of a brute force fix and there’s probably a better way, but it gets the job done.
If you don’t already have all of the libraries I posted recently (https://github.com/EnviroDIY/Libraries) get them and then simply change the include statements at the top of your sketch to look like this:
Arduino12#include <Sodaq_PcInt_Mod.h>#include <SDI12_Mod.h>You don’t have to change anything else in your sketch, the modified libraries will handle everything the same.
“20V-1A” is just the rating of the protection diode on the PC board. When choosing a solar panel for the Mayfly, you should only connect ones that are listed as 6 volt panels, and do not use a 9-volt or 12-volt panel.
The charging circuitry on the Mayfly isn’t capable of charging 2 parallel battery packs simultaneously, so it’s not advised to connect two packs to the Mayfly if you ever connect a mucroUSB cable or solar panel to it because either of those will start the charging process.
The second LIPO connector on the Mayfly is for providing a direct connection to the battery for high-current accessories like a GPRSbee module. It’s not supposed to be used to provide a secondary battery input for the Mayfly.
However, if you take precautions to make sure you never connect a microUSB or solar panel, then theoretically it’s possible to connect two parallel batteries to power the Mayfly, but you run into the usual issues related to parallel battery operation, like making sure both batteries have identical capacity and are charged to the same initial voltage, along with other precautions. Given the dangers of short-circuiting LIPO batteries and causing a fire, EnviroDIY does not recommend that users connect more than one battery to their Mayfly at a time.
Also, if you connected 2 LIPO batteries at once, you can’t use the onboard LIPO charging circuitry on the Mayfly, so there’s no benefit to using LIPO batteries and you might as well just use a single high-capacity battery pack of a different chemistry (like lead acid or alkaline) if you’re looking for longer lifespan.
The sample code above will not work properly until you’ve correctly changed the channel number for each of the 6 sensors. Also, once you do that and you have a different number of sensors other than 6, you’ll need to change the number in line 31 to the correct number of sensors.
So first you should make sure you change the channel number of one sensor at a time and then verify that the sample code for reading one sensor works properly before proceeding further.
To connect a Decagon 5TM probe to your Arduino board, connect the sensor bare braided wire to a ground pin of the Arduino. Connect the white sensor wire to 5V, and connect the red sensor wire to the data pin (pin D7 in the example above).
It’s not currently available in Europe, but we’re working on it!
The circuit components are rated to the industrial temperature range of -40C to +85C, but I think at extreme temperatures you’re more likely to encounter problems with your battery rather than the Mayfly circuit. LiPo batteries don’t perform well at either really cold or really hot temperatures, so you might consider a different type of battery chemistry if you’re deploying it long-term in a harsh environment.
Last winter, a number of my Mayfly loggers saw -20 degrees on a number of occasions according to the logged temperature of the onboard DS3231.
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