I made a line follower with one QTRX-HD-03A and two QTRX-HD-01A on both sides, which worked really well for a while. It worked really well for a few days, but then one of them stopped working. I spent about 10 minutes trying to figure out what had happened, and sure enough, the other two stopped working too.
I had another QTRX-HD-01A, so I thought I’d try it out with an adapter (5vdc). I saw the light with my phone, but after a few minutes, when I tested it out again, it wasn’t working either.
I’d be really curious, what could be the possible reasons and I’ve bought some other new sensors, what tips do I need to pay attention to in order not to have the same problem?
It is unusual for us to hear about these types of sensors suddenly not working. Can you double check that all your wiring is still okay and post some pictures of the setup that show all of your connections? Please provide more details about how you are trying to use the sensors (e.g. microcontroller and power source) and exactly how they are behaving now.
Here are my connections. I connected 5v and gnd from an esp32 powered board called Deneyap Kart 1A V2. I used these yellow wires and two of the blue wires on the side as sensor wires and connected them to the analog pins on this board. Everything was fine but it happened suddenly, even though the vehicle was not moving (because there was no line) there was no physical damage.
The Deneyap Kart 1A V2, supported by an Esp32 progresor, is powered by a buck converter that gives 5.0V as output. This converter was powered by a 4s LiPo.
Between how blurry your picture is and how low the resolution is, it is hard to tell anything useful, but some of the soldering looks like it might be questionable. I suggest addressing that first. The Adafruit Guide To Excellent Soldering is a great resource for that.
If you are still having trouble with your boards after that, could you post updated pictures that clearly show both the top and bottom sides of the boards? A broader picture showing the rest of the connections in your system (including the connections to your microcontroller) could also be useful.
Additionally, please let us know what happens now when you try to use the sensors now. For example, do they return anything in your program, and if you the monitor voltage on the sensor output pins with another device (like a multimeter or oscilloscope), are there any signs of life?
The workshop where my sensors are located is locked for a week. By the way, I tried to read the voltage with a multimeter, it reads about 2-3 volts, but it doesn’t change when I put my finger on the phototransistor or shine a light on it.
It was the same on the serial monitor on the computer. I know the soldering won’t look good but I put some tubing over the wires close to each others in the middle. This way it worked fine for a week, I didn’t change anything. I can send a clear picture after 8-9 days, is that ok?
Unfortunately, running electronics like this with poor connections is like rolling dice: it might work for a while, but at any point you might get a bad roll and see problems or even potentially damage your boards, which might have been what happened here. Whenever you are able to clean up the soldering and post a clearer picture, we will be happy to look at it for you.
Another issue I recognized is you said you are powering the board with 5V, but ESP32 devices usually use a 3.3V logic level, so that would be the appropriate source for your QTR sensors. It might be a good idea to check the if the pins you were using on your ESP32 controller still work by testing them with another analog signal or even by just temporarily connecting a voltage divider to them.
