The code below is an attempt to read the state of a switch on pin 16 of an ESP8266-12E
It uploads OK but it fails to operate properly. Everything worked fine while I was just setting a LED and reading an analog input.
Is the approach below suitable or is there a better way?
#define BLYNK_PRINT Serial // Comment this out to disable prints and save space #include <ESP8266WiFi.h> #include <BlynkSimpleEsp8266.h>
bool current = 0;
bool previous = 1;
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "xxxxxxx";
void setup()
{
Serial.begin(9600);
Blynk.begin(auth, "xxxxxxx", "xxxxxxx");
pinMode(16,INPUT_PULLUP);
}
void switchstate(){
current = digitalRead(16);
if (current != previous){
previous = current;
if (current == LOW)
{
Blynk.virtualWrite(3, "CLOSED");
}
else
{
Blynk.virtualWrite(3, "OPEN");
}
}
}
void loop()
{
Blynk.run();
switchstate();
}
@donold I can’t see a lot wrong with your sketch but a few things I would recommend:
It is normal practise to use Simple Timer or Ticker to time events rather than putting them in the loop. So perhaps every second call switchstate() from Simple Timer or Ticker.
I always thought virtual pins were referenced with a V but the new 32+ seem to ONLY work without the V. Might be worth trying pins 0 to 31 with a V.
Is your switch wired LOW or HIGH, is it a momentary switch?
I would avoid GPIO 16 as one day you might want to use that pin (and only that pin) for deepsleep.
I guess my main problem is understanding how to get the indicator on Blynk to write “High” or “Low” as I expected from the code. Also when I run it I just get pulsing of my LED, The frequency part is not needed as it should only write when the switch changes state.
I think that simple timer may be better and will implement it
Will try with a V to see what happens
It is not momentary
Point taken I will change it shortly.
Do you know of any simple examples of how to read a switch state and the appropriate Blynk settings?
Take a look at Button Poll in the More, Examples of the IDE but change from Ethernet to ESP.
#define BLYNK_PRINT Serial
#include <SPI.h>
#include <Ethernet.h>
#include <BlynkSimpleEthernet.h>
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "YourAuthToken";
void setup()
{
Serial.begin(9600);
Blynk.begin(auth);
// Make pin 2 default HIGH, and attach INT to our handler
pinMode(2, INPUT_PULLUP);
}
int prevState = -1;
int currState = -1;
long lastChangeTime = 0;
void checkPin()
{
// Invert state, since button is "Active LOW"
int state = !digitalRead(2);
// Debounce mechanism
long t = millis();
if (state != prevState) {
lastChangeTime = t;
}
if (t - lastChangeTime > 50) {
if (state != currState) {
currState = state;
Blynk.virtualWrite(V1, state);
}
}
prevState = state;
}
void loop()
{
Blynk.run();
checkPin();
}
Thanks Costas your example worked.
Will tidy it up a bit and try the Simple Timer trick as it is probably a better approach.
I often find that it sometimes takes a few upload attempts before it is successful. Do others experience these problems or am I unique?
Maybe it’s because I get cheap eBay ESP8266 boards. I am waiting on delivery of a better (more expensive anyway) board.
Some upload attempts respond like this:
error: Failed to open COM3
error: espcomm_open failed
error: espcomm_upload_mem failed
It eventually uploads successfully. I never have problems with a standard Arduino Uno. The ESP8266 boards seem to be a bit hairy. I don’t think it’s my power supply but will investigate further. I have got a 2200uF cap across the supply which maybe a little under rated at only about 200mA capacity. Once successfully uploaded there are no problems.
I think many people have problems uploading to the ESP’s but when you consider the price of an ESP with and Arduino plus a shield the ESP wins hands down.
If you go for something like the WeMos D1 Mini and set the upload speed to 115200 you should get close to 100% upload success. Excellent product for $4 and no messing about with capacitors and the like.
