ESP8266 Community Forum

- Thu Jan 21, 2016 11:39 am #39378 That's not really a job for a 555, it's more suited for 7400 or CD4000 logic ICs. Basically what you need is a flip-flop, a latch or a shift register, there are plenty of those available in both IC families.
A 74HC595, 74HC173 or 74HC75 for example should all do the job...

- Thu Jan 21, 2016 12:13 pm #39379 i would try to use them, i see it http://www.learnerswings.com/2014/08/am ... ation.html , but i don't undestand how can i switch on a specific led using 74hc4017.
Can you explain me how can i integrate it with the gpios of the ESP8266? Consider that i have not more gpios, i need to use the impulse that i send to the hbridge. So for example , gpio2 HIGH for 100ms, it is sent tothe hbridge , than to the 74hc4017 , it is possible to switch on the led2 only with this impulse?
Second step. gpio2 LOW, esp sends a impulse to hbridge to switch off the valve, and sends the same impulse to the 74h... Is it able to switch off the led?

thanks

- Thu Jan 21, 2016 7:29 pm #39403

i would try to use them, i see it http://www.learnerswings.com/2014/08/am ... ation.html , but i don't undestand how can i switch on a specific led using 74hc4017.

That's a counter, you can't set individual outputs, it will only enable one output at a time and cycle to the next one on each pulse.

Can you explain me how can i integrate it with the gpios of the ESP8266? Consider that i have not more gpios, i need to use the impulse that i send to the hbridge.

Assuming you have 2 GPIOs per valve and toggle the device by pulsing the GPIOs either H-L or L-H, a S-R latch should work (e.g. 74HC279).

If that's not the case, please provide a complete schematic.

- Mon Jan 25, 2016 4:20 pm #39684 I don't undestand the real use of this 74hc279. It has 2xSets and 1XReset per channel, and i don't undestand how can i manage them with my configuration.
For example:
i have gpio4 that close the relay with a pulse and gpio16 that open it. I what my led is switched on when the relay is closed.
So --->
1) esp sends a pulse from gpio4 to l293d (that sends +- to the relay for the set status)----> the same pulse arrives to the 1s1 of the 74hc279 , and so q1 is H (+ is arriving to my led)
2) esp sends a pulse from gpio16 to l293d (that sends -+ to the relay for the reset status) ----> the same pulse arrives to ??? 1s2 or 1r?? Of course i want switch off the led now.
thanks