I don’t know how many times I’ve written bad Arduino code to call a function every few milliseconds. Sometimes this bad code works well enough for my sketch to actually work. Often, it either doesn’t work at all or does something I really didn’t expect.<\/p>\n
So on Arduino Day 2017<\/a>, I’m glad I found out about bhagman\/MillisTimer: A Wiring and Arduino library for working with millis().<\/a> It couldn’t be simpler to use: include the library, write the function you want to call every N<\/em> milliseconds, set up the timer to run every N<\/em> millis, and put As an example, here’s the eternal \u00e2\u20ac\u0153Hello, World!\u00e2\u20ac\u009d of the embedded world, Blink<\/a>, rewritten to use MillisTimer:<\/p>\n Note that MillisTimer only triggers when I don’t know how many times I’ve written bad Arduino code to call a function every few milliseconds. Sometimes this bad code works well enough for my sketch to actually work. Often, it either doesn’t work at all or does something I really didn’t expect. So on Arduino Day 2017, I’m glad I found out […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[7],"tags":[2207,3048,2573],"class_list":["post-13880","post","type-post","status-publish","format-standard","hentry","category-computers-suck","tag-arduino","tag-arduinod17","tag-timer"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pQNZZ-3BS","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/13880","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/comments?post=13880"}],"version-history":[{"count":4,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/13880\/revisions"}],"predecessor-version":[{"id":13883,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/13880\/revisions\/13883"}],"wp:attachment":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/media?parent=13880"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/categories?post=13880"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/tags?post=13880"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}timer.run()<\/code> in a loop that’s called frequently. The library handles the timing and resetting all by itself.<\/p>\n\r\n\/\/ MillisTimerBlink - blink LED every second\r\n\/\/ using Brett Hagman's MillisTimer library\r\n\/\/ https:\/\/github.com\/bhagman\/MillisTimer\r\n\/\/ (or use Sketch \u00e2\u2020\u2019 Include Library \u00e2\u2020\u2019 Manage Libraries \u00e2\u20ac\u00a6 to install)\r\n\/\/ scruss - 2017-04-01\r\n\r\n#include <MillisTimer.h>\r\nMillisTimer timer1; \/\/ new empty timer object\r\nconst int led_pin = LED_BUILTIN; \/\/ use the built-in LED\r\n\r\nvoid flash() { \/\/ function called by timer\r\n static boolean output = HIGH;\r\n digitalWrite(led_pin, output); \/\/ set LED on or off\r\n output = !output; \/\/ toggle variable state High\/Low\r\n}\r\n\r\nvoid setup() {\r\n pinMode(led_pin, OUTPUT); \/\/ use built-in LED for output\r\n timer1.setInterval(1000); \/\/ set timer to trigger every 1000 millis\r\n timer1.expiredHandler(flash); \/\/ call flash() function when timer runs out\r\n timer1.setRepeats(0); \/\/ repeat forever if set to 0\r\n timer1.start(); \/\/ start the timer when the sketch starts\r\n}\r\n\r\nvoid loop() {\r\n timer1.run(); \/\/ trigger the timer only if it has run out\r\n \/\/ note that run() has to be called more frequently than the timer interval\r\n \/\/ or timings will not be accurate\r\n}\r\n<\/pre>\ntimer.run()<\/code> is called. Sticking a delay(2000)<\/code> in the main loop will cause it to fire far less frequently than the interval you set. So it’s not technically a true periodic timer, but is good enough for most of my purposes. If you want a true interrupt-driven timer, use the MsTimer2<\/a> library. It relies on the timer interrupts built into the Arduino hardware, and isn’t quite as easy to use as MillisTimer.<\/p>\n","protected":false},"excerpt":{"rendered":"