Aaron posted an update 4 years, 2 months ago
@srgdamiano Hi Sara, I’m new to the Mayfly and trying to get a handle on the output power as it’s not quite as intuitive as the arduinos I’m used to working with. I’d like to connect a MatixBox MB 7383 ultrasonic sensor requiring a 5v power supply. I see there are both digital and analog grove connectors featuring a power and ground pin with a jumper to switch between 3.3 and 5 volts (I assume you simply swap the position of the attached jumper?). However, I’m not getting any voltage reading across these grove pins. I don’t get any voltage across the Sw5 pins either (I thought those were power supply?) and only get 3.3v as expected across the 3v3 and gnd pins on the analog and digital rails. I understand these are basic questions, but I’m having trouble finding detailed instructions – could you point me in the right direction? Many thanks.
You should post this in the forum, not as a status update.
The Sw5V and Sw3.3V power are controlled by pin 22 on the Mayfly. To get 5V, you must both switch the jumper and set pin 22 high in your program. The 7383 operates at 2.7-5.5V, so you shouldn’t need 5V, 3.3 should suffice.
There’s a simple example with one of the Max Sonars here: https://github.com/EnviroDIY/EnviroDIY_Mayfly_Logger/blob/master/examples/mayfly_sonar/mayfly_sonar.ino
There’s a bit more detail about the connections and how to use the MaxSonar with modular sensors here: https://github.com/EnviroDIY/ModularSensors/wiki/MaxBotix-MaxSonar