{"id":14065,"date":"2016-01-20T20:21:11","date_gmt":"2016-01-20T19:21:11","guid":{"rendered":"http:\/\/www.recantha.co.uk\/blog\/?p=14065"},"modified":"2016-01-20T20:21:11","modified_gmt":"2016-01-20T19:21:11","slug":"fading-leds-using-pwm-with-gpio-zero-on-the-raspberry-pi","status":"publish","type":"post","link":"https:\/\/www.recantha.co.uk\/blog\/?p=14065","title":{"rendered":"Fading LEDs using PWM with GPIO Zero on the Raspberry Pi"},"content":{"rendered":"

\"fading_leds\"<\/a><\/p>\n

The project<\/h2>\n

GPIO Zero<\/a>, the new GPIO library from the Raspberry Pi Foundation, is becoming my go-to method for doing simple things with the Pi’s GPIO pins. Over the past couple of weeks, I’ve been having fun preparing for the Bett exhibition, and more specifically the Raspberry Jam that is being held there on the 23rd January.<\/p>\n

Part of my exhibit is a Raspberry Pi Zero with a Scroll pHAT attached. Getting that working was a story in and of itself, but I want to focus today on the 4 LEDs I soldered onto some prototyping board that is attached to the Zero. You can see them in the picture above.<\/p>\n

Back to GPIO Zero. It contains a class called PWMLED which allows you to do software PWM<\/a>\u00a0with LEDs. What this means is that instead of just blinking them on and off you can fade them in and out. This takes a little bit of doing (unless I’ve missed something) so I thought I’d share with you my method. One thing to understand is that I’ve done it in a ‘thread’, which means that while the Scroll pHAT is doing it’s job of displaying messages, I can have the LEDs doing something disconnected from that process. The individual functions, however, could be removed from inside the threading ‘object’ if you don’t need to do anything else except pulse the LEDs.<\/p>\n

Here’s a video to prove that it works!<\/p>\n