Know How...

Aug 3rd 2017

Know How... 333

LED Clock Build Part 4

It's time to put together the base!
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Category: Help & How To
It's all about that base... We show you how to put together the components needed for nearly completing our LED Clock Project!
  1. Arduino Nano ~$3
  2. Tiny RTC ~$1 (in 5pk)
  3. 2 x UBEC ~$5
  4. 12V Power Supply (12V 5A 5.5mm) ~$7
  5. Power Jack Socket ~$1
  6. 10k Resistors (x4) ~$1
  7. Push Buttons (x3) .35 (in 20pk)
  8. Diodes (x2) ~$2
  9. Jumper Leads ~$3
  10. 30AWG Silicone Wire (Red/Black/White) ~$3
3D Printed parts
  1. LED Clock Base
  2. Left Channel Cover
  3. Right Channel Cover
  4. Left Column Cap
  5. Right Column Cap
  6. Base Cover
  7. Base Buttons
  1. Soldering Kit
  2. Wire Strippers/Snips
A few things about the base:
Let's talk about POWER!!!
  • We need to create a "power budget" by looking at all the components in our build, determining their max draw, and adding a safety margin.
    • 86 LEDs (60 second LEDs, 15 minute LEDs, 11 hour LEDs) * 60ma = 5.1amps. (5.1a * 5v = 25.5 watts) 25.5 Watts
    • We want a safety margin, so we're adding 20% to the total. (~5 watts safety = 30.5watts) 30 Watts
  • We need a PS that can supply 30 watts
  • We also need a UBEC that can provide those 33 watts
    • Our regular UBECs can only do 15 Watts (maximum of 25 watts)
  • We're using 2 UBECs b/c they're only rated for 3A each. (We're tying them together)
    • UBEC 1: Second Ring (60 LEDs * 60ma = 3.6A)
    • UBEC 2: Minutes/Hours/Arduino (26 LEDs * 60ma = 1.5A) + 25ma for the NANO
  • We can get away with this because the 30Watts is WORST CASE SCENARIO... and it would only be in animation mode with ALL the lights at full brightness. (The surge rating of the UBECs can handle that)
  • We don't want the Nano to try to supply power to the LED's when we're programming it via USB, so we're going to add two diodes to keep power from feeding back to the LEDs from the NANO.
  • We're going to use three inputs to control our clock
    • Button 1: Mode
    • Button 2: Increase
    • Button 3: Decrease

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