Hello - I have a mini pro 3.3v. it gets power and my pc and arduino software see it when I do not have anything hooked to the vcc pin. I have a jsn-sr04t-2.0 hooked to the vcc pin, ground and two or the digital pins. When it is hooked up, the mini does not power. I thought the vcc was both and input and an output depending on other power being supplied.
How is the Pro Mini powered? You can get 3V3 power from the Vcc pin if you power the Mini by teh RAW pin, or of course if you use the other Vcc pin to power the board. As you didn’t tell us how exactly you wired your setup we cannot help you further.
Your description is rather confused. If you have a 3.3 V Pro Mini, then it requires a 3.3 or 5 V power supply fed to the Vcc pin. You cannot power it using the “RAW” pin if there is any other module connected to Vcc.
So what are you using as a power supply?
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Showing what you have connected and what voltages you are using please?
Do you have a DMM?
The sensor is rated <8mA working current, so it can be hooked to Vcc. You are doing something wrong
Hint: the sensor and cable is waterproof, not the board!
If the Mini is powered from a USB to serial cable like FTDI, the voltage at the Vcc pin is 3.3V, what voltage (and current) does the jsn-sr04t-2.0 require?