Close
0%
0%

Clock7

A 3D printed, illuminated, colored, connected, smart powered, 7 segmented clock

Public Chat
Similar projects worth following
0 followers

Clock7

Clock7 is a 3D printed, illuminated, colored, connected, smart powered, 7 segmented clock

This project was inspired by the design of the beautiful but discontinued ClockONE by Twelve24 kickstarter and more recently brought back to my memory by the Huge Seven Segment Display made by engineerish.

The goal of this project is to create a wall clock made out of 4 of these huge seven segment displays and connected somehow by two dots in the middle separating the hours from the minutes so the final things looks like the ClockONE. The clock will be illuminated by a strip of WS2812B commonly named NeoPixels so that the 7seg displays can be controlled individually, and so the brightness and color of the light can be changed.

  • A little forethink

    Nathan Bleuzen10/28/2018 at 15:02 0 comments

    Electrical requirements

    Powering the LED strip

    The rule of thumb for the WS2812B is that each LED with its driver can consume up to 60mA when set to white full brightness RGB(255, 255, 255). The clock will be made of 4 7segs display, each having 7 segments (duh..!), made out of 4 LEDs. That's a total of 112 LEDs. If we count 4 LEDs for each dot that will be in the middle of the clock that's a grand total of (tadaaaa!) 120 LEDs. This is quite convenient since you can buy a 2 meters strip of WS2812B with 60 LEDS by meter from AliExpress for cheap.

    Therefore, we have: 120LEDs * 60mA = 7.2A

    Not all LEDs will be on at the same time, and even if I'm not sure they will run at full brightness. Using a 10A 5V we can make sure we don't run out of power and the power adapter will only run at a fraction of its maximum output resulting in better efficiency.

    Driving the LED strip

    The second electrical issue is that the ESP8266 board (I'm using a ESP12E NodeMCU) is running on 3.3V whereas the WS2812B needs the data line to be run at, at least 0.7 * VCC. When powering the strip at 5V to have the rated performance the threshold of 3.5V is to high for the ESP. However as the board has an onboard voltage regulator we can supply the board with 5V from the power supply on the Vin pin without having to step it down to 3.3V, which is nice.

    Back to the data line problem. We need to make a 5V signal (at pretty high speed since the WS2812B use a 800kbps data-rate) to a 3.3V level. Different ways to that exist.

    One would be to lower the power supply of only the first LED to lower the threshold on the data line, at the output of the first pixel the data line will be rectified higher to the same level that the VCC and pass it to the next pixel using 5V. The problem with this method is that we loose brightness on the first pixel.

    The way I choose to go is to use a bus transceiver level shifter that can shift a signal from 5V to 3.3V. For some reason I had a hard time using it and making it work. After multiple models of level shifters tried without successfully operating the LED strip I tried using an other Arduino library than the Adafruit one. Using the NeoPixelBus library with a level shifter worked where the Adafruit one didn't.

  • Some planning

    Nathan Bleuzen10/28/2018 at 14:47 0 comments

    First iteration of the project:

    • Displaying the time as a 24h digital clock using the LED strip with pure and bright white light.
    • The time will be fetched from an external API so the DST and time zone will be already taken care of.
    • Using the 3D printed enclosure of the clock, an ESP8266 and a 5V 10A power supply.

    Planned improvements to the clock:

    • Add color and brightness shifting depending on time of the day.
    • Add a companion weather station (also based on a ESP8266 platform) with a REST API to display temperature, humidity and atmospheric pressure as well as weather forecast from an external API using light animation on the clock.

View all 2 project logs

Enjoy this project?

Share

Discussions

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates