[Shannon Hicks]

What sketch are you running? Is it a sample from this forum, or from our Github repo, or something you wrote?

[Shannon Hicks]

The AREF pin of the micro on the Mayfly is not tied to anything (except through a capacitor to ground as suggested in the ATmega datasheet), so when you use the standard analogRead(0) command, it uses the default 3.3v reference setting. If a user is more advanced and wants to use an internal reference by using certain commands, or by connecting an external reference to the AREF pin of the lefthand 20-pin header, then those options are available. However, it is extremely dangerous to adjust the AREF voltage either externally or internally if you can’t make sure that the analog pin won’t see a voltage exceeding the new reference voltage, otherwise permanent damage to the microprocessor will occur. See the Arduino page for example commands and warnings about how to do it safely. https://www.arduino.cc/reference/en/language/functions/analog-io/analogreference/

I can’t imagine needed a finer resolution on the battery measurement though, it’s already pretty fine scale as-is on the default setting and is accurate enough to know your general battery health, plus the LiPo batteries we use have internal low-voltage cutoff protection so they will stop supplying power to the Mayfly if their voltage drops too low.

[Shannon Hicks]

That simple Xbee serial printing example doesn’t require any additional libraries installed in you IDE or called by your sketch. All it is doing is printing text to the 2 separate hardware serial ports on the Mayfly.

I have never used the programmable versions of the Xbee 900HP. There are infinite combinations of ways to configure an Xbee module and its network, and it gets complicated really fast once you start changing things and adding features. So when I set up my network years ago, I kept it really simple. You first have to program the modules with the X-CTU software before they can be used. I keep them in the same basic configuration that they’re shipped in. Transparent, AT mode, 9600 baud, but I set them as end nodes and not coordinators (my base station is set as the coordinator and never sleeps). The end nodes are set to pin-sleep mode so that the Mayfly wakes them when it’s time to send data. So the Mayfly just drives a pin low (Xbee modules sleep when pin high, and wake when pin low) to wake the module, send it a line of serial text at 9600bd, and the Xbee transmits that line to the coordinator (who’s always awake), and then the Mayfly puts the Xbee back to sleep and then the Mayfly sleeps. I found that sending serial data from the Mayfly to the Xbee module using anything faster than 9600bd will sometimes throw a corrupted character in there occasionally, which messes up the receiving sketch on the coordinator’s UnoEthernet basestation. So it’s best to keep serial communication between the Mayfly and bee modules at the default 9600bd.

[Shannon Hicks]

The Mayfly’s bee footprint was originally set up to only power modules that require moderate current supplied to the Vcc pin of the module, such as Xbee RF modules (900Mhz and 2.4Ghz), Bee wifi, and Bee bluetooth. There are even GPS modules with the Bee footprint that work great on the Mayfly. Then when we started using 2G and 3G cellular modules from SODAQ, they have their own separate JST sockets for connecting them directly to the LiPo battery, thus supplying sufficient voltage and current (they require ~3.7v and up to 2A). But other brands of cellular boards, like the Digi 4G board, don’t have the external power connection option, so the only way to power them is through the Bee header on the Mayfly, which is why I added the SJ13 option on the latest v0.5b Mayfly boards. So just cut the small trace that’s connecting the center pad of SJ13 (labeled BEE_Vcc) to the 3v3 pad, and put a solder bridge joining BEE_Vcc to the pad labeled LIPO.

[Shannon Hicks]

We have successfully used dozens of Xbee Pro 900HP radios with Mayfly boards for our logger network here at the Stroud Center and at other locations. You can program the modules to be in “pin-sleep mode”, meaning you can toggle the sleep mode by driving a pin high or low. You can also use cyclic sleep and other “smart” sleep methods if you want to implement a mesh network. In our locations, we’re fine with just a central coordinator that stays constantly powered and connected to an ethernet jack. Whatever radio traffic it hears from the sleeping logger nodes, it relays to our online database. I wrote about it earlier this year in another thread: https://www.envirodiy.org/topic/connecting-to-the-internet/

Nowadays you can buy dedicated base station modules that do the same thing as my homemade version, but almost 6 years ago when I first built it, there were very few reliable and affordable options.

The 900MHZ Xbee radios have a much better range in our forested terrain than the 2.4GHZ radios. In open and relatively flat areas, I’ve gotten almost a mile of distance between the logger and the base station. Your results will vary depending on the gain and placement of your antennas, and probably more importantly the topography and forest density. In terms of battery usage, they are very efficient when compared to the cellular modules we use in the hundreds of areas where we don’t have a base station. The radios sleep constantly just like the loggers, and when it’s time for a transmission, they are powered for a fraction of a second and then return to sleep.

I use both the RPSMA modules as well as the U.FL models, depending on what sort of enclosure I’m mounting the Mayfly in.
I use weatherproof bulkhead RPSMA fittings that mount the antenna on the enclosure, and sometimes they are a continuous, 1-piece design with a u.fl connector on the inside end. It also depends on how much physical abuse the radio module is going to see. The RPSMA fittings are much more appropriate if you’ll be moving the board or cables around frequently, since the u.fl connectors are somewhat fragile and finicky, and will fail quickly if you make-break the connection too many times.

[Shannon Hicks]

For more than a year now, all boards, either the ones bought separately or as part of the starter kits, are the latest v0.5b. The only difference between the .5 and .5b is the power options for the bee socket via jumper SJ13 to give you the option of powering the bee socket either from 3.3v Vcc of the board (default) or directly from the LiPo socket if you cut the trace and add some solder to jump it to the LiPO setting.

I know I’ve posted in the forum about the change between versions, but I just noticed that it isn’t noted on the Mayfly jumper settings webpage, and the photo is of the much older v0.3 board. I’ll try to update those soon. Same thing with the Amazon photos, I’ll have to update those when I get a chance to take and edit new photos of the latest boards. I’ve just been too busy building and deploying new stations this summer, and keeping up with everything required for testing, prepping, and shipping all the new boards to Amazon.

[Shannon Hicks]

Our Amazon inventory is back up and running again. Some of you have noticed and already ordered some boards and kits. We should be able to keep the storefront stocked unless there are a lot of large purchases. If you know you’re planning to order more than a dozen boards soon, I’d appreciate a heads up so that I can plan our inventory accordingly.

Also, if you purchase any of our items you’ll notice that now all of the packages have a warning sticker on them stating the potential for cancer risk. This is a requirement by the California Proposition 65 that goes into effect this week that requires any product sold in the state that contains certain chemicals must have a warning label on the product, as well as in the catalog listing. So you’ll find a sticker on each item we sell, in addition to the Prop 65 statement on the Amazon listings. This is because all 4 of our products contain printed circuit boards, and there are a few chemicals used in the production of all circuit boards that requires us to use the Prop 65 statement. It’s nothing to worry about, we are just meeting the new labeling requirements necessary for selling items to anyone in the state of California.

[Shannon Hicks]

Are you connecting to the Mayfly directly using the onboard microUSB jack, or a separate FTDI adapter connected to the FTDI jack on the Mayfly? Are any LEDs powered on the Mayfly when you turn it on? I hand-check and program every Mayfly board when it leaves my workshop with a sketch that blinks the red and green LEDs and prints the temperature to the serial port every second at 9600 baud. Assuming the board hasn’t been reprogrammed by whoever sold it do you and that it’s still functional, you should see that kind of response from the board even before you attempt to program it yourself. Since you bought it on Ebay, I have no way of knowing whether the board is functional since the seller must have bought it from us on Amazon and is then reselling it. It’s definitely not an authorized, direct-from-EnviroDIY board.

[Shannon Hicks]

Yes, I’ve done it before where the logger sends alerts directly from the station, but it’s usually easier to implement this using a script on whatever server you’re hosting your data on. Because if you want to change the value of the trigger points, or do some filtering of single spikes that occur during low turbidity (like from trash or fish that get in the way of the sensor during a single reading), or a slope analysis of the 5 most recent records, a very simple script can do that on the server, and then react by sending an alert to whatever destination you choose, which you can also change and update as frequently as you want on the server without having to visit the logger to reprogram it.

[Shannon Hicks]

There are 3G and 4G modules that work just fine with the Mayfly. Are you meaning you want instructions on how to do it, or you’re just looking for the hardware?

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