Remember the MacBook breathing sleep light?
The slow breathing sleep light from older MacBooks, recreated with one 555 timer and two transistors. About twelve breaths a minute.
Free build sheet
The parts, every wire with its length and bend points, a bend guide, both sides of the board and checkboxes to track your progress. Print it or keep it open at the bench.
Open the build sheetWhat you need
11 parts on a perfboard 14 × 28 holes, plus hookup wire.
| Qty | Part | Where to buy |
|---|---|---|
| 1 | Ceramic Cap100nF C1 | Buy Ceramic Cap on Amazon |
| 1 | Ceramic Cap10nF C2 | Buy Ceramic Cap on Amazon |
| 1 | Electrolytic Cap100uF C3 | Buy Electrolytic Cap on Amazon |
| 1 | Power Input (2-pin) J1 | |
| 1 | LED LED1 | Buy LED on Amazon |
| 2 | NPN Transistor (TO-92) Q1, Q2 | Buy NPN Transistor (TO-92) on Amazon |
| 1 | Resistor (axial)4.7k R1 | Buy Resistor (axial) on Amazon |
| 1 | Resistor (axial)33k R2 | Buy Resistor (axial) on Amazon |
| 1 | Resistor (axial)330 R3 | Buy Resistor (axial) on Amazon |
| 1 | DIP-8 U1 |
Check every pin against the datasheet of the exact part in your hands before wiring.
As an Amazon Associate I earn from qualifying purchases.
Cut list
19 wires, 467 mm (18.4 in) in total, in the order the build sheet cuts them. Wire numbers match the build sheet. Each length includes 5 mm per end to go through the hole.
| Wire | Colour and net | Length | ||
|---|---|---|---|---|
| 6 | BlackRAMP G15 → H16 | G15 → H16 | 14mm | Straight |
| 12 | Black9V G3 → L3 | G3 → L3 | 23mm | Straight |
| 18 | BlackGND H3 → F8 | H3 → F8 | 28mm | 10mm (90°) |
| 17 | BlueGND K5 → H5 | K5 → H5 | 18mm | Straight |
| 5 | BlueRAMP D18 → E15 | D18 → E15 | 20mm | 13mm (90°) |
| 11 | Blue9V C6 → G5 | C6 → G5 | 23mm | 15mm (90°) |
| 4 | GreenLED_A K16 → I20 | K16 → I20 | 25mm | 15mm (90°) |
| 16 | GreenGND M11 → M5 | M11 → M5 | 25mm | Straight |
| 10 | Green9V F12 → J9 | F12 → J9 | 28mm | 15mm (90°) |
| 1 | RedCONT K10 → J11 | K10 → J11 | 14mm | Straight |
| 7 | RedRAMP F14 → H12 | F14 → H12 | 17mm | Straight |
| 19 | RedGND E9 → E16 | E9 → E16 | 28mm | Straight |
| 13 | Red9V I8 → I18 | I8 → I18 | 39mm | 9mm (45°), 31mm (90°) |
| 3 | WhiteDISCH C12 → G12 | C12 → G12 | 20mm | Straight |
| 9 | White9V D7 → E11 | D7 → E11 | 23mm | 15mm (90°) |
| 15 | WhiteGND K26 → K11 | K26 → K11 | 48mm | Straight |
| 2 | YellowDARL J15 → K17 | J15 → K17 | 18mm | 10mm (90°) |
| 14 | Yellow9V H17 → K18 | H17 → K18 | 20mm | 8mm (90°) |
| 8 | YellowRAMP J16 → G8 | J16 → G8 | 38mm | 25mm (90°) |
About this build
Remember the breathing sleep light on older MacBooks? Apple drove theirs with pulse width modulation, per its Breathing Status LED Indicator patent. This board gets a similar slow fade a different way, with an NE555 and no code.
The fade comes from the ramp on the 555's timing capacitor, a 100uF that charges and discharges slowly. Two 2N3904 transistors buffer that ramp, so the LED follows it without dragging the capacitor down. It comes out to about twelve breaths a minute.
Run it from 9V. On 5V the ramp never gets high enough to light the LED.
MacBook is a trademark of Apple Inc. This is an inspired-by recreation of the effect, not Apple's circuit, and PerfBoard is not affiliated with or endorsed by Apple.
More builds
See all builds
VideoThe Stranger Things light wall, from two chips
Six coloured LEDs light one at a time in a loop, like the Christmas light wall in Stranger Things. A 555 timer and a counter.
13 parts · 28 wires
LightsTimers and logic
VideoA traffic light that counts to five
Red, yellow and green LEDs that cycle like a traffic light on their own. A 555 timer, a decade counter and four diodes.
15 parts · 27 wires
LightsTimers and logic
VideoThe Clapper, recreated: lights that turn on when you clap
Clap once and an LED turns on, clap again and it turns off. A microphone, two transistors and one flip-flop chip.
14 parts · 24 wires
SensorsLights