Trinket lends itself very well to building clock projects, its small and easy to hide behind a larger display. And clocks don’t need a lot of logic, this example only has maybe 20 lines of code. Adding a digital display via I2C is possible using seven segment or character-based displays (with the library code posted for other projects).
This project interfaces Trinket to the the Adafruit DS1307 real-time clock (RTC) breakout board to form a clock. But in a twist, the display is done using two analog meters. One for hours, one for minutes.
The Trinket can output to a meter without digital to analog converters. Trinket has pulse width modulation (PWM) on three of its pins. The meter uses a moving coil inductance movement, acting to average the indication of current flowing through it. If you have narrow pulses, the average voltage it sees is lower, thus the current is lower for the fixed resistance attached to it. For wide pulses, the meter sees nearly the supply voltage and will stay around the full scale. This circuit varies the pulse width sent to the meters proportional to the hour of the day and the minutes after the hour.
For two meters, we will use two of the three PWM pins on Trinket (the third is also an I2C pin connected to the clock module).
There are several projects on the web using analog meters to tell time. The ease at which you can do this with Trinket allows you to build this type of clock quickly and compactly. You may focus on designing how to mount the meters in a creative way.
There are many ways to display the finished project. Rather than a cabinet or plexiglass display, I chose meters free-floating in a colorful box. I think it lends a modern look.
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 – we’ll post the link there.
Join us every Wednesday night at 8pm ET for Ask an Engineer!
Maker Business — How 3M is able to ramp up production of N95 masks
Wearables — Hot glue magic
Electronics — Have you met Charlie?
Biohacking — Vitamin-C + Gelatin for Accelerated Recovery
Python for Microcontrollers — Fifty Blinka Boards, Python Survey Out, CP 5.4.0 Beta 0 and more! #Python #Adafruit #CircuitPython @circuitpython @micropython @ThePSF
Adafruit IoT Monthly — Quarantine Clock, Smarter Than your Speaker, and More!
Microsoft MakeCode — Arcade Mini Game in a Text Adventure
No comments yet.
Sorry, the comment form is closed at this time.