Hi, I'm running three ultrasonic sensors (HC-SR04) from an Elegoo UNO R3 with the voltage supplied to them from a 9v battery connected to a Power MB V2 (a little external power supply).
I've gone through 6 ultrasonic sensors now (3 and then 3 again) and they keep frying themselves (not immediately but after a while of use). Why is this happening and how do I stop it?
I've checked the voltage at the pins of the sensors and it's a steady 4.96v.
I'm wondering if power surges could still be the problem and would wiring in a capacitor to mitigate those or a resistor to lower voltage overall help?
I know it's the sensors that keep dying because I can plug in a fresh one and it works fine.
Can you post a schematic of your circuit and some clear photos of how it's wired together?
Under what kind of environmental conditions does this system operate?
Is there anything else going on in the project? Other parts or such? The HC-SR04 are one of the times you can just use the 5V regulator of the Arduino, since they have a working current draw of only 15mA each.
Sensors, or anything do not fry themselves it is you that are frying them by doing something wrong.
It is a funny sort of fine that results in only working for a short time. This sort of thing is caused by you abusing the sensors in some way, but not too much as to fry them instantly but enough to severely shorten the life of the sensor. It is how all the abuse of any electronic components work.
Abuse here means operating the component outside the parameters given in the manufacturer's data sheet.
So until we know what you are doing, and a schematic is the only way to show us then we can't help you further.
Note a good photograph of your system is not a substitute for a schematic. It's only use is for us to check that you wired it up lke your schematic says.