GPIO

Introduction

The ESP module can control things with it's build-in GPIO output pins. We can turn these on or off or we can set these pins to a special Pulse modulated value (PWM output). And it's also possible to send short pulses (single puls) to one of these pins to control specific devices that are switched with a single short high or low signal.

Hardware

It's best to connect a LED to the GPIO to test your setup. You could dim this LED with the PWM mode commands. Be aware that the ESP8266 only supplys 3,3v at a max current of only ~10mA.

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ESP Easy

You dont need a Device definition (task) to control basic GPIO output. You can always control all the pins by HTTP.

Basic on/off

We can control a pin with simple http url commands. To change the pin to high or low steady output:

http://<ESP IP address>/control?cmd=GPIO,<pin>,0

http://<ESP IP address>/control?cmd=GPIO,<pin>,1

PWM control

To set a certain PWM level:

http://<ESP IP address>/control?cmd=PWM,<pin>,<level>

If you have set a certain GPIO to a PWM level and want to use it as a regular HIGH/LOW pin you need to reset by setting the PWM level to 0 or 1024.

http://<ESP IP address>/control?cmd=PWM,<pin>,0, this will leave the GPIO status LOW.

http://<ESP IP address>/control?cmd=PWM,<pin>,1024, this will leave the GPIO status HIGH.

Short pulses

To send a pulse to a certain pin:

http://<ESP IP address>/control?cmd=Pulse,<pin>,<state>,<duration>

Example to send an active high pulse on GPIO 2 for 500 mSeconds:

http://<ESP IP address>/control?cmd=Pulse,2,1,500

Long pulses

A long pulse is basically the same as the plain pulse. The only difference is the time base in seconds rather than in milliseconds. So it's more suiteable for longer durations. To send a long pulse to a certain pin:

http://<ESP IP address>/control?cmd=LongPulse,<pin>,<state>,<duration>

Example to send an active high pulse on GPIO 2 for 10 minutes:

http://<ESP IP address>/control?cmd=LongPulse,2,1,600

Servo motor control

To control a Servo Motor:

http://<ESP IP address>/control?cmd=Servo,<servo nr>,<pin>,<position>

We currently support a maximum of two servo motors so you can build a pan & tilt device if you like.

Example to set servo 1 on gpio-0 to a 90 degree position and servo 2 on gpio-2 to a 45 degree position:

http://<ESP IP address>/control?cmd=Servo,1,0,90 http://<ESP IP address>/control?cmd=Servo,2,2,45

Tones

From ESPEasy v2.0.0-dev6 (in the testing plugin set) its also possible to play a tone on a pin, via a speaker or piezo element:

http://<ESP IP address>/control?cmd=tone,14,1300,200

Plays a 1300 hz tone for 200 ms on gpio-14h

Melodies and ringtones

From ESPEasy v2.0.0-dev6 (in the testing plugin set) its also possible to play melodies via [RTTTL]

(dont forget to remove the spaces)

http://<ESP IP address>/control?cmd=rtttl,14:d=8,o=5,b=180,c6,b,c6,p,g,g-,p,f,b,c6,p,d6,p,g,p,c6,b,c6,p,d6,p,f,g,g-,4p,g,f,4d-

This plays a melody on pin 14.

You can also use these from rules. We use it to let our alarm system give feedback to the user via a piezo speaker.

To make a boot-sound on startup, create a rule like this:

On System#Boot do 
  rtttl,14:d=10,o=6,b=180,c,e,g
endon