[Solved] I can't find the info I need

@davee Indeed it is a 3.3V board, but with a USB connection, and a 5V input plus a tiny 1117 VR chip. Before I connected the pin labelled 5V the board did nothing. I just tried using one rail in 5V and the other in 3.3V. Still no change.

@will There is no 100 ohm resistor. There is a std 150 ohm resistor in line with the LED. The blue led is just there, no idea why. I think it's tied to pin 13. strangely it has now stopped after the last change.

@davee It's just a pin to pushbutton, and when the code detects the pushbutton it fires the led. I am really beginning to thig that digitalRead does return LOW when the button is pushed and HIGH when not. Like I said, I can easily fix the logic with a ! but wanted to know for y personal education how the digitalRead works,

@davee The only pin to worry about is the push button pin and I can put that on my 3.3V rail. The led is between a pin and ground so no worries.

Posted by: @zander

@will There is no 100 ohm resistor.

The 100 ohm resistor is the one present in the diagram for pull-down resistors in the URL I mentioned above. It's not necessary.

I think @davee is right, i think we need to see the circuit diagram to see what's connected to what. I know I'm very confused.

My WiFi is very flaky tonight (it is free) so I may not be on much.

@will I will draw one by hand and post it when I am able.

@zander 

Ok, thanks. Good luck with your reception.

Here it is

Hi @will and @zander,

Assuming it is the same as at https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/

(and also assuming it follows the same 'general pattern' as the ESP32, which I have played with a little)

I have just found a schematic on https://www.botnroll.com/en/esp/3558-lua-nodemcu-v3-wifi-module-esp8266-32mb-ch340g.html

which if it 'matches' your board confirms my suspicisions.

I would have hoped that the board worked with just the USB connected, at least as far as being able to download a program ... though until you connect some other bits, there will be no 'action' to see of course. Of course, sometimes USB leads are troublesome, etc...

However, it is perfectly ok to supply 5V to the Vin pin, and supply Ground to board ground, to provide an alternate supply.

The point is all of your other connections, for resistors, switches, LEDs and so on, should only connect to ground ... for 0V, or one of the 3.3V outputs from the board ... they should NEVER go anywhere near the 5V supply!!

I am still looking for a 'neat' explanation of the circuit, but essentially:

150 ohm resistor ... one end to 3.3V from board, other end to LED anode

LED cathode to chosen GPIO output pin

10k resistor ... one end to 3.3V from board, other to chosen GPIO IO input pin and one side of switch

Other side of switch to ground.

............

Unfortunately, If you have connected a GPIO pin to the 5V supply, e.g. via the switch, you may have damaged either that port or the whole processor. If one GPIO pin doesn't work, it might be worth trying another.

I am always the pessimist, but your observation that the blue LED isn't lighting does not sound great ... looking at the schematic, it is tied in with a trick for resetting the chip that I haven't completely figured out, but I don't see why it should have changed without a reason.

Hope you get it to work ... I haven't looked at your code ... see if you can at least get the code to download from the IDE, and provide an update.

Best wishes, Dave

@will @davee I found this bit of trivia on Random Nerds. In am beginning to think this board just works differently.

@davee The code is in the thread. 5V has never touched the input pin as far as I know, but trying another pin is possible. 

The output side is obviously working fine and is not a part of the problem.

The only problem is closing the circuit from a digital pin to Grd with or without a 10k resistor between the pin and ground. I will go double check all the wiring and try the resistor on the pin side.

When wired as I showed earlier the board blue led comes on, then when I press the button the board blue led goes out and the red led turns on.

When I add a 10k resistor between the pin and ground, the board blue led comes on and the red led comes on at 1/2 intensity. Pressing the button does nothing.

I will try another board.

Hi @zander,

I have just seen your sketch ... the 5V connection to the LED is definitely wrong .. it should be to a 3.3V line.

The switch to ground is fine. The action of the switch needs to change the voltage at the GPIO pin between 3.3V and 0V. Adding a 10kOhm (approx) resistor between 3.3V and the GPIO pin means that when the switch is open, the resistor will pull the voltage on the GPIO pin up to 3.3V, but when the switch is closed, the GPIO voltage will be zero.

If you have a multimeter, it is worth measuring the voltage at the GPIO pin, with the other meter lead connected to ground - you should be able to see it is 3.3V before you press the switch, and 0V, while you hold the switch pressed. (Yes, you might wish you had 3 hands to do it... 😀 )

With the Arduinos, it is alternately possible to slightly change the program to select the internal pull up resistor ... this is basically the same as the 10k I have just described, but it is already available inside the chip. I haven't checked if the ESP8266 provides the same functionality.

And of course, LED needs to be wired in the right way round ... it's is all too easy to plug it in 'backwards' ... this will not usually do any harm at low voltages... but it won't light up either. And, of course, a multimeter check on this pin might reveal something interesting.

Good luck .. I hope you can get your board to work.

Dave

Posted by: @zander

Here it is

For some reason I can't attach pictures tonight.

To your diagram as shown, take a 10K resistor and put one leg at the junction of the button and the wire to buttonPin. Put the other leg of the resistor on VCC or 3.3V but NOT 5V.