User:Chotee/NoFeedback-ManagementIntervention

1mx1m screen of RGB lights that slowly and independently change colour. All patterns are just your mind playing tricks on you.

Parts

• [Ordered] LEDs - https://nl.aliexpress.com/item/free-shipping-500pcs-5mm-Straw-Hat-Colorful-Slow-Flashing-Flash-RGB-Red-Blue-Green-LED-Leds/32231092414.html
• 11 x duct (11*€3.19) https://www.gamma.nl/assortiment/kabelgoot-kunststof-wit-20x10-mm/p/B651828
• 10 Bouten M5x80mm €8 - https://www.gamma.nl/assortiment/gamma-slotbout-m6x80-mm-verzinkt-20-stuks/p/B458213
• 1000x1000mm Plexiglas - €23 - https://www.gamma.nl/assortiment/martens-acrylplaat-transparant-100x100-cm/p/B151681
• 2 x 1m 5mm staal/hout

Electronics

• 500 Slow color changing RGB leds.
  • max led forward current is 20mA.
  • RGBs forward-voltage oscillates between 3.2v and 3.8v (±15%)
  • LEDs max continious current at 20mA.
• 22x22 leds (484) [sqrt(500) = 22.36..]
• Powered by 12v PC PSU or 20v LT power-brick.

12v

• 12v/3.8 (V-max-led-forward) = 3.15 LEDs; 3 LEDs in a chain.
• There are 161+1/3 chains [484/3]
• Vmax = 3 * 3.8Vf = 11.4v; 0.6v left.
• Vmin = 3 * 3.2Vf = 9.6v; 2.4v left.
• current limit power-max: 2.4v*20mA = 48mW.
• Total Current: 20mA * 162 = 3.24A
• Total power: 3.24A * 12v = 38.8w

20v

• 20v/3.8 (V-max-led-forward) = 5.2 LEDs; 5 LEDs in a chain.
• There are 96.8 chains [484/5]
• Vmax = 5 * 3.8Vf = 19v; 1v left.
• Vmin = 5 * 3.2Vf = 16v; 4v left.
• current limit power-max: 4v*20mA = 80mW.
• Total Current: 20mA * 97 = 1.94A
• Total power: 1.94A * 20v = 38.8w

Components

• R1 = 100k
• R2 = 1k8
• Rs = 10
• Opamp >20v;
  • OPL best fit: LM358DR (But has two channels) -- €1.17 (100pcs) -- https://nl.aliexpress.com/item/10PCS-LM358DR-SOP8-LM358-SOP-LM358DT-SMD-LM358DR2G-new-and-original-IC-free-shipping/32533323519.html
  • *Single* channel opamp: LM321 -- €1.99 (100pcs) -- https://nl.aliexpress.com/item/Free-Shipping-100PCS-100-NEW-LM321MFX-LM321MF-LM321-A63A-SOT23-5/1924012475.html -- http://www.ti.com/lit/ds/symlink/lm321.pdf
• Mosfet. >20v; >20mA:
  • From the OPL: BSS138W-7-F; 50V; 200mA -- €1.36 (100pcs) -- https://nl.aliexpress.com/item/50PCS-BSS138LT1G-SOT23-BSS138-SOT-MOSFET-SMD-new-and-original-IC-free-shippin/32518915182.html -- http://www.onsemi.com/pub/Collateral/BSS138LT1-D.PDF

== Circuit: [from http://www.falstad.com/circuit/circuitjs.html]

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w 544 512 416 512 0
w 416 496 416 512 0
v 416 496 416 224 0 0 40 12 0 0 0.5
g 416 512 416 544 0
w 416 224 544 224 0
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f 688 384 752 384 0 1.5 0.02
162 752 224 752 272 1 3.2 1 0 0 0.01
162 752 272 752 320 1 3.2 1 0 0 0.01
162 752 320 752 368 1 3.2 1 0 0 0.01
r 752 448 752 512 0 10
w 544 224 752 224 0
w 544 512 608 512 0
w 608 512 752 512 0
w 544 480 544 512 0
w 752 400 752 448 0
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w 608 400 608 448 0
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a 608 384 688 384 1 15 -15 1000000 0.2121490597382403 0.21218074656188607
r 544 272 544 368 0 100000
w 544 272 544 256 0
r 544 368 544 480 0 1800