ESP8266 Community Forum

- Thu Jun 04, 2015 1:50 pm #19459

Ok, interesting development.

Using the 5v-3.3v board and booting with GPIO-2 unplugged it now consistently boots. Then I can plug in GPIO-2 to the led and I can control it. This is completely disconnected from the FTDI now.

So presumably it doesn't like the potential of current flow through GPIO-2 on boot?

It will not boot if it sees low level at GPIO2 during power-up. You need to connect your LED to Vcc instead of GND. The LED will then light up when GPIO is set LOW and vice versa.

- Sat Jun 06, 2015 6:30 pm #19700 Just wanted to say thanks both for your help.
Led prototype working I moved onto my main goal, a PIR sensor that sends a GET request with params to a local web server. Will be encased in a small drain pipe section which will deliberately narrow the PIR field of view to act more like a"trip wire ". All as part of a security system.

Only thing is I've not figure out how to get the gpio2 to not go low while booting when attached to the PIR. I may have to put in an additional switch, or build a timer in with a transistor and capacitor.

I never thought I would succeed in getting this far. Many thanks goes to the devs of the Arduino ide incorporation as well. Made it so much easier than before.

- Tue Jun 09, 2015 6:36 am #19913

Only thing is I've not figure out how to get the gpio2 to not go low while booting when attached to the PIR.

Using one basic NPN transistors (2N2222, BC547 or similar) and two resistors as an inverting buffer between the PIR output and the GPIO will ensure any output from the ESP during startup will not reach the sensor. Yes, three (small though) parts but at almost zero cost.