Comments (7)
Is it because stato
is being logged to the console instead of value
?
from onoff.
No it's just a typo in the question. Fixed.
PS. I'm using Raspbian on a Raspberry Pi B.
from onoff.
I would expect stato
to have a value of off
in the example program, so everything appears to be function correctly.
This line of code creates a new Gpio object called led
with an initial value of 0:
led = new Gpio(17, 'out');
This line of code reads the value of led
and sets value
to 0:
led.read(function (err, value) { // Asynchronous read.
This line of code therefore sets stato
to off
var stato = (value == 1) ? "on": "off";
What makes you think salto
should be equal to on
?
PS. Please don't modify previous posts as it makes it difficult/impossible to understand the topic later.
from onoff.
So how can i read the value of led without setting it to 0?
Doesn't exist a way to read the pin state?
And for example how would you implement a toggling function without reading
the current pin value?
from onoff.
There appears to be a misunderstanding here. Reading the value of a Gpio object for a LED will _NOT_ set it's value to 0. What will set it's value to 0 is creating a new Gpio object for the LED. If the program is continuously creating Gpio objects for the LED, then the value will continuously be set to 0. This should be avoided.
Please try the following program and let us know if it functions correctly. It toggles the state of a LED on GPIO 17 every 200ms, 25 times:
var Gpio = require('onoff').Gpio,
led = new Gpio(17, 'out');
(function blink(count) {
if (count <= 0) {
return led.unexport();
}
led.read(function (err, value) {
led.write(value ^ 1, function (err) {
});
});
setTimeout(function () {
blink(count - 1);
}, 200);
}(25));
from onoff.
As you suggested, every new Gpio object sets the value to 0. Thanks, now all works fine ;)
from onoff.
That's good news :)
from onoff.
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from onoff.