Shannon Hicks

The way a voltage divider works is for you to use 2 resistors in series, and then you measure the junction between the two resistors, and you’ll see a fraction of the overall voltage. The best method for breaking a 5v signal down to something the Mayfly can tolerate would be to use two identical value resistors (like 10k-ohms each), so that way…[Read more]

Also, you need to use 3.3 volts as the board voltage in your conversion formula and not 5.0 volts. And if you’re measuring a 50/50 voltage divider, you’ll then need to double the measured voltage to get the true sensor voltage. So:

float voltage = (sensorValue * (3.3 / 1023.0)) * 2.0;

You mean the USB5V on the FTDI header? That’s only used if you’re supplying power to the board via an FTDI adapter when programming. You should definitely be using the SW5 pin for powering a sensor and not using the FTDI header.

What does your resistor divider network look like? What values, and how do you have them connected in relation to…[Read more]

What pin is the sensor getting power from? If it’s the Switched 5v pin (labeled SW5), or from one of the grove terminals (assuming you’ve moved the jumper over to the 5v setting), you still need to switch on the 5V boost regulator by putting this line, preferably in your setup routine:

digitalWrite(22, HIGH);

The 5v boost regulator (as well as…[Read more]

Which analog pins of the Mayfly are you attempting to use to measure the voltage? And can you share the code you’re using to read the voltage?

Some of you have already noticed that the Mayfly boards and kits are back in stock on Amazon. If you’re planning to order more than a dozen of any item, I’d appreciate an email at mayfly@envirodiy.org so that we can tell you if there’s enough of that item in stock or to find a better way to get you the larger quantities.

For the past few years, we’ve only offered the vertical microSD card adapter as part of the starter kit. But if there’s significant demand for it, I suppose we could add it to our Amazon store as a separate item.

Here’s some sample code that I just put together to demonstrate the code for waking and sleeping the Xbee. You’ll notice it’s a little more complicated than just setting the D23 pin high or low. That’s because the pin should be pulled high when you want to sleep the Xbee (like I mentioned in my previous post), and if you want to sleep the Mayfly…[Read more]

We had a big run on boards and kits the past couple weeks, I guess it’s the spring monitoring season again. I usually try to keep the Amazon store well-stocked, but we sold more in the past few weeks than we did the previous 2 months, so I’m working on replenishing the Amazon inventory ASAP. I sent some boards to Amazon last week which should be…[Read more]

To address your points:
1. Any power source connected to the 2 pins labeled “Ext 12v” will power the Mayfly but will not charge any LiPo batteries connected to the two LiPo jacks.
2. The solar panel connected to the JST jack labeled “SOLAR” should never exceed 6 volts. The charging circuity on the Mayfly uses a small chip that has a 6v…[Read more]

Yes, it is possible for a Mayfly logger to read data from a Sontek SL sensor. Several years ago when we first started using the Mayfly, we connected it to Sontek IQ+ units, which have basically the same power and data interface requirements that the Sontek SL units do. The sensors need 12 volts DC to operate, which the Mayfly can’t provide…[Read more]

I bought some of the Xbee3 LTE-M modules a few weeks ago and they had hardware version D printed on them, so they appear to be the latest version. I also updated their firmware to a version that came out a few weeks ago which supposedly has some improvements too. Digi also states in the manual several time (including with big warning symbols)…[Read more]

For small orders, we only sell through our Amazon storefront. But since you need a large order, it’s best to contact us directly to see what we can do for you. You can send me an email at mayfly@envirodiy.org and we can continue the discussion there.

The Grove 6-pin screw terminal adapter board is now available on Amazon: https://www.amazon.com/dp/B07PVKQVH8

The OBS sensor comes a with bare-wire cable with 6 leads. Three of them need to be connected to the Mayfly ground (sensor power ground, sensor signal ground, and sensor shield). Then the 3 other sensor wires get connected to the remaining 3 pins of a Grove terminal (note, you have to use one of the two Aux A/D Grove inputs only). Seeedstudio…[Read more]

We currently don’t sell the screw terminal adapter, but I’m working on getting them to Amazon this week. I’ll post an update here when they are available.

The Mayfly can handle up to 16v input without risk of blowing anything up. I designed it that way so people can power it with a 12v battery that’s also attached to a charger, so their battery sees up to 15v sometimes, but still won’t hurt the Mayfly.

The cable I usually use for the ultrasonic sensors is this McMaster-Carr part number: 8233T32

It’s a CMR rated 4-conductor, stranded, shielded, 22ga cable. It also happens to have a CMX rating which makes it sunlight resistant and suitable for outdoor and wet locations. Most other mult-conductor cables (like the kind you can find at the local…[Read more]

Yes, that cable option should be fine. I’ve made my own waterproof housing for the sensor end using a threaded PVC coupler and a cable gland since that’s cheaper. You won’t need a 6-pin screw terminal since there’s only 3 wires to connect (power, ground, and data). You can connect a 4th line to the start/stop pin of the sensor if you want to…[Read more]