[Shannon Hicks]

Another option for connecting a sensor’s 3.5mm stereo headphone plug is to use these stereo jacks:
https://www.amazon.com/uxcell-Stereo-Female-Adapter-Connector/dp/B013D1U90S
Just strip the black, red, and white wires of a Grove cable and solder them to the corresponding terminals of the jack.

And the easiest way to do it is to use our custom Grove-to-3.5mmStereoJack adapter board:
http://envirodiy.org/wp-content/uploads/grove_stereo.jpg
We hope to have these in our Amazon store later in April.

[Shannon Hicks]

The boards are $60. They were in stock last week, but sold out very quickly. We are working to get more inventory soon.

[Shannon Hicks]

The Xbee socket is powered from the main regulator, which can source 500ma. If your radio was having trouble drawing current, you’d probably see strange behaviour on the rest of the board. Are you powering anything power-hungry at the same time as the radio? What kind of antennas are you using? Xbee units have a default power setting of “high”, have you changed that or are you using the default configuration? Have you tried monitoring the current while the radio is transmitting?

For what it’s worth, I have used lots of Xbee and Xbee-Pro modules, both 2.4Ghz and 900Mhz, and there are a lot of different factors that influence the signal range. What kind of range are you currently getting and at what frequency?

[Shannon Hicks]

Here are some links to photos of the boards.

Version 0.3:
http://envirodiy.org/wp-content/uploads/20170319_022350.jpg

Version 0.4:
http://envirodiy.org/wp-content/uploads/20170319_022329.jpg

Version 0.5:
http://envirodiy.org/wp-content/uploads/20170319_022228.jpg

[Shannon Hicks]

I’ve taken hundreds of photos of the various versions of the boards, but we only post the resized photos here on the website. I think the highest resolution one currently online is this one:

http://envirodiy.org/wp-content/uploads/2016/05/20160508_134514-001.jpg

I can certainly upload some other photos if you’d like a different angle or with other accessories like what comes with the Starter Kit.

I just finished taking photos of the new version 0.5 board that should be available on Amazon any day now, so I’ll be sure to put a high-res version online in case anyone wants that too.

[Shannon Hicks]

How did you verify that the board isn’t going into sleep mode? Can I assume that you didn’t modify the pads on JP1 and that the clock interrupt is still connected to A7 and you didn’t do anything with D10 other than use the D10-D11 grove port for connecting your sensor?

[Shannon Hicks]

We’ve been busy getting the Mayfly and starter kits back in stock, so now that they’ll be online any day now, we can work towards getting the proto boards listed, so look for those in early April.

[Shannon Hicks]

For anyone wanting an update on the Mayfly availability, the boards arrived at my office last week from the manufacturer, and after thorough testing of each one, I sent off the first shipment of them to Amazon. Once Amazon has incorporated them into their fulfillment system, the product listings will show that they are in stock and can then be purchased. In the meantime, I’ll be working on updating the documentation on this site to include information about the new features and specifications of this version (v0.5).

[Shannon Hicks]

There are several different methods you can use to wake a sleeping processor using a realtime clock. The example I posted uses the method of triggering an interrupt pin on the processor by using a quick pulse that the RTC puts out every minute. By doing this, the processor can wake up each minute and then it’s up to the user’s code to examine the current time and either do something or go back to sleep and wait another minute. I used this example since it’s the easiest for other people to choose whether they want to do something every minute or every 5 minutes or any other interval. You could certainly wake the processor only at select times by using the alarm feature of the RTC. It looks at the current time (3:30 for example), then adds a specific interval (15 minutes) to determine what time the next wakeup event should be (3:45), then puts the processor to sleep and it won’t wake up again until that interrupt at 3:45. There are some other Arduino libraries that you can use for interacting with the RTC and setting alarms instead of using the Sodaq_DS3231 library that I used in that example. Just search the web for example sketches for setting alarms on the DS3231. Keep in mind that the Mayfly board’s default pin is A7 for reading the square wave alarm output from the DS3231, which is why you also need the Sodaq_PcInt library (this library allows other pins to be used as interrupts besides the board’s regular hardware interrupts of D0, D1, and D10). If you really want to use a hardware interrupt instead of the pin change interrupt, you can modify the solder jumper SJ1 on the back of Mayfly boards version 0.4 and greater by cutting the trace to the A7 pad and solder jumpering to the D10 pad.

But I prefer to just wake it up every minute since it’s simpler for my purposes. When using this method, the processor is really only awake for a few milliseconds each minute, and it’s so quick that you can’t see it when looking at the board’s current draw on an ammeter. So waking a Mayfly for a few milliseconds each minute really has no greater draw on the overall power consumption than than letting it sleep continuously and only waking at longer intervals.

[Shannon Hicks]

I’m not sure where you saw something that said the Mayfly only supports a 2.5W panel, because that’s not accurate. The only limiting thing is the voltage that the panel produces — the Mayfly only works with panels with an output voltage of 6 volts. If you use a solar panel with a 9v or 12v output, you will damage the Mayfly.

The reason for the voltage limitation is the MCP73831 charge controller chip on the Mayfly board. It can’t handle input voltage above 6 volts. It also has a maximum useful input current of 500ma, so if you do the math (Ohm’s law) you can calculate that a 3-watt panel will provide 500ma of current. So for sunny locations, any panel that supplies more than 3 watts is overkill. If you are in a shady location, or in areas that don’t get at least an hour of direct sunlight, then using a larger panel like the 3.5-watt (https://www.voltaicsystems.com/3-5-watt-panel), 6-watt (https://www.voltaicsystems.com/6-watt-panel), or even 9-watt (https://www.voltaicsystems.com/9-watt-panel) might be useful. The 9-watt panel puts out 3 times more current than the Mayfly can use (1500ma) but if your logger is really shaded, then the efficiency of the panel drops significantly, but even at 33% output, it would give same power as a 3W panel in full sunlight, and the maximum useful current the Mayfly will accept.

We usually use the 2-watt panel (https://www.voltaicsystems.com/2-watt-panel) in almost all of our locations because they are sunny enough to keep the battery charged. But in a few areas we use the 3.5-watt and have had great results, so we’ve never needed to use anything higher than that.

If you’ve already got a 12-volt deep cycle battery and separate 12v panel and charge controller, then it probably makes more sense to power your Mayfly board from the 12v battery and not use a 3.7v LiPo to power the Mayfly, and then you don’t have to use a separate 6v panel just for the Mayfly. To power the Mayfly from 12v, you have to use a 12v-to-5v adapter like this one (https://www.amazon.com/HitCar-Inverter-Converter-Recorder-Straight/dp/B00U2DGKOK) and plug it into the microUSB port on the Mayfly. There is an external battery header (unpopulated) on the Mayfly (version 0.3 and 0.4 boards), but it has a maximum input voltage of 5v. The upcoming Mayfly version 0.5 will be able to accept a connection directly 12v batteries, but for the older boards, you’ll need to use the 12v-to-5v adapter. It’s easiest to use the ones that have the microUSB connector on them, but you could also use one with bare wires and connect that to the external battery header using a polarized 2-pin connector with 0.1″ pitch.

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