Hi.
Answering your questions.
1) Does the sensor values cross the threshold value? Have you tried experimented your LDR separately with a simple sketch and see if it works as expected?
2) In the diagram, it is just to show that both need to be powered with 5V. They don’t need to be connected together. Have you tried the DHT22 sensor with a DHT sample sketch and see if it works?
Do you get any errors or do you have any more information about these issues?
Regards,
Sara

Not sure what is going on.  I replaced my first board with another and it also stopped working, apparently now unusable.
I don’t want to lose a third board, so for now I’m abandoning this project, but would appreciate any suggestions what could possibly destroy boards.

Hi Jack.

Taking a look at the photo, it seems that everything is alright. However, I can’t be sure of the DHT connections just by looking at the picture. You can try powering the DHT with 3.3V instead of 5V.

That PIR motion sensor works with 5V, did you modify it to work at 3.3V?https://randomnerdtutorials.com/modifying-cheap-pir-motion-sensor-to-work-at-3-3v/

Are you sure the board is dead? How is its behavior?

Without further information, it is very difficult to figure out what might be wrong.

Regards,
Sara

Generally the only thing that can kill a board is shorting VCC to GND or overpowering a pin. Most times overpowering a pin will only kill that pin so you could try a different pin. Always make sure you have a resistor on a pin to limit current. Always make sure a pin is voltage tolerant before connecting a voltage. Ie. A 3.3V tolerant pin will not tolerate 5V.

Ugh… replaced with a third board – dead.   I’ve lost three boards now.  I know they are dead because the LEDs don’t come on and Device Manager doesn’t detect it.   I am powering this from a PC USB, but that is how I’ve always done it.

When do they die? What do you have to do to kill it? I guess it’s possible you have a bad USB cable or PC USB port. Try a hub and another cable.

It’s frustrating to lose boards…at least they are pretty cheap, but still…
I’m confused by one thing–you said “I am powering this from a PC USB” but in the top left of your picture, I see the green adapter which is typically hooked up to an external power supply.
You have to program the ESP32 by hooking up the USB, but if you had that hooked up at the same time as the external PS, that would not be good.
But I’m just guessing–can you clarify?

.

I found the source of the problem.   The lesson describes connecting to separate 5v power sources – one to the board, another to the light/relay, so that shouldn’t be a problem   But the power provided to the light/relay which I thought was 5v was 10v.

:   (      Oh well.  Bad to have a loss, but always good to know why.  Next time I double check everything, not just the breadboard.

Hi Jack.
I’m glad you’ve found the source of the problem.
I hope you still have more boards to continue your projects 🙂
I’ll close this issue. If you need further help, you just need to open a new question in our forum.
Regards,
Sara

Sara    I understand a 5v output should have been used, but how to determine what amps can be tolerated?   I have some 1amp adapters and some 2.5amp .

It’s not so much how many amps can be applied but how many can be drawn. You could plug in a 5V 10amp supply but that’s the maximum that could be drawn before the power supply would start to overheat. The circuit itself may only draw 100mA. So always use a power supply that can handle at least the maximum the circuit can draw. Preferably way more.

Thanks Steve. I thought that was the case but wanted to check first. 

Of course if you do short a 10amp supply you will get a bigger bang/fire than if you short a 500mA supply but, hey, a fire is a fire right? 😉

Steve, you mentioned earlier to always use a resistor in front of a pin.   How to calculate what size resistor to choose with different components?   The resistors covering the LDR, PIR, DHT22 and RGB were not all the same.  Determine this by looking at the data sheet of a component?

Yes. Use the data sheet of the component. They tend to have examples and I always use those.

OK, looking closer, I see that the external PS is connected to the light through the relay; therefore, it should be isolated from the rest of the circuit. If that’s true, the only thing the external PS can fry is the light, and there must be some other reason for the board failing.

I second Steve’s recommendation to look at the datasheet for examples, but there’s no simple rule like “always use a resistor in front of a pin”–it all depends on the rest of the circuit.

For a general troubleshooting approach, I would start out with a simple circuit and get that working, then add things one by one and see what happens.

I ended up finding the multisensor circuit, and then I was trying to map that to your picture. As I was looking at it, I noticed one wire (see closeup). It looks like there is a yellow jumper shorting 3.3v to ground, although it’s difficult to tell from the angle. If that’s the case, you are going to blow the poor little voltage regulator on the board.

P.S. Back in college I was a TA in the digital electronics lab, so looking at these boards brings back memories 🙂

Bob  Thanks for your feedback.
That yellow wire bridges over an apparent gap in the long breadboard on the hot side.  It looks like it goes to ground, but that’s not the case.
Regarding your comment about the power to the relay, I blurted out without thinking and of course it calls for a 12v lamp and if anything I should have fed 12v not 10v.   So I’m still unclear what killed the boards.
Are you suggesting I can use the same code but add in each component?   If I replicate the same wiring would I not eventually kill another board?