Is a MPR121 captouch chip being funky? Change the baseline @FairywrenTech
Are you working with MPR121? Does it at times start being screwy, having one channel get jammed, or another become unresponsive? Congrats, you’ve stumbled onto this IC being too smart for its own good according to Arya’s Bread Crumbs blog.
MPR121 is a wonderful capacitive touch sensing IC. It can do so much for you – all of that automatically, too. One of the things it does, is ongoing baseline calibration. It can adjust to electrode capacity changing over time, so that even if you go into different environment, your touches still get registered. Well, this is the norm for any self-respecting IC, but I digress. Also, this means it can adjust to you hotplugging electrodes!
What if you have a stable electrode configuration (say, all of your bananas and apples are already connected with jumper wires) and it glitches in some way, as it seems to often happen with mine?
What can you do? Well, you can have the IC calibrate for a certain baseline, and then lock that baseline in – disabling baseline tracking.
The blog shows MicroPython code to disable the baseline. Read more in the post here.
Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.
Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7:30pm ET! To join, head over to YouTube and check out the show’s live chat and our Discord!
Python for Microcontrollers – Adafruit Daily — Python on Microcontrollers Newsletter: New Python Releases, an ESP32+MicroPython IDE and Much More! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi
EYE on NPI – Adafruit Daily — EYE on NPI Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey