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This project makes a working 7-segment digital clock by routing colored light from an 8×8 WS2812B LED matrix through flexible, side-emitting PMMA pipes into printed digit lenses. The optical path—not a conventional screen—is the centerpiece: each pipe carries light to a segment, and a small gap at the lens face softens the glow.
Make: lists the build at 38 hours, moderate difficulty, and $0–$50. Those are the publication’s planning estimates, not a current itemized cost or a guaranteed completion time. The design and build instructions are by Terra Gilbert in Make: Vol. 84.
How the light-pipe clock works
An 8×8 addressable LED matrix supplies the light. Flexible, side-emitting PMMA pipes route light from selected matrix positions to individual white lenses that form the clock’s seven-segment numerals. The pipes fit into conical, slightly undersized holes in the printed base, while the lenses snap into the face.
The pipe ends do not press flush against the digit lenses. Gilbert explains that the slight air gap diffuses the light into a smoother glow. The project’s visual effect depends on the alignment of the matrix, pipes, and lenses, so this is a build where careful physical fitting matters as much as wiring.
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- The led light guide fiber is used for creating a beautiful lighting atmosphere. Widely used for coffee house, swimming pool, home, park, etc..
- Outside diameter of the PMMA fiber optic cable is 2mm, with 1 meter or 3.3 ft length. The operating temperature range is recommended to be controlled in 0 to 180 Fahrenheit.
- The optical fiber emits bright color (light source is not included here), with good optical conductivity and flexible enough.
- Put the fiber cable into your led light gap first, then create the shape what you need.
- The light source needs to be purchased separately, here is not included.
Parts, tools, and printed components
Electronics and materials
- One WS2812B 8×8 LED matrix.
- One ESP8266 D1 Mini-type board.
- One MPU6050 accelerometer/gyroscope module.
- Two 10-foot lengths of 3 mm (0.12-inch) side-emitting flexible PMMA cable.
- White and black PLA filament.
- Standard-A to Micro-B USB data cable.
- Hookup wire and one M2×6 mm machine screw.
Tools and software
- 3D printer and a slicer such as Cura.
- Soldering iron and solder, wire strippers, screwdriver, and a computer with Arduino IDE.
- Optional snips and hot-glue gun.
Print set
Print one black base, one black face, one black underside lid, and 28 white lenses. Make: says the parts need no supports and recommends a brim for the underside lid. The source does not specify printer settings such as layer height, nozzle temperature, or infill, so use settings appropriate to your printer and filament rather than assuming a universal profile.
Build and assembly sequence
- Print the enclosure parts. Download the project’s STL files from the Make: project page, then print the base, face, underside lid, and 28 lenses in the specified colors.
- Prepare and upload the firmware. Download
ClockSketch_v7-7SCv3-TFO-3.inofrom the project page. In Arduino IDE, enter the local Wi-Fi network’s SSID and password in the sketch, connect the ESP8266 over USB, and upload. Gilbert describes this sketch as a modification of Daniel Cikic’s ClockSketch V7 for this clock. - Wire the electronics. Solder the circuit according to the project schematic. Route wires beneath the MPU6050 and ESP8266 so they do not push the LED matrix out of its rails.
- Fit the controller and sensor. Secure the MPU6050 in the underside lid with the M2×6 mm screw and slide the ESP8266 into its slots. Test the circuit before closing the enclosure. Turn the assembly upside down to check the gyro-triggered color change.
- Close the enclosure. Install the underside lid with its opening aligned to the ESP8266 micro-USB port, then fit the face.
- Route and fit the pipes. Start with the row closest to the face. Follow the project’s grid-to-digit mapping, cutting and inserting pipes incrementally. Leave each piece slightly long so it keeps tension and does not fall out; the pipe should catch roughly halfway into its lens. Snap the lenses into the face as you proceed.
- Check the display. Confirm that the seven-segment digits show the clock time and that the color response changes when the assembled clock is turned upside down.
Why the enclosure grips the pipes mechanically
Gilbert describes trying a large clear-PETG block, then a smaller version that concealed the pipes, and an acrylic enclosure she found messy. The final design uses conical, slightly undersized mounting holes to hold the PMMA pipes by friction. She reports that super glue, hot glue, and UV-cured acrylic resin did not hold the pipes in her attempts; those are her project observations, not controlled comparative tests.
Rank #2
- Length : 236" fiber optic and tube.
- Fiber diameter 2mm, pipe diameter 3mm
- PMMA light guide cable with 6mm skirt
- Only optical fiber, does not include LED light sources
- Universal suitable for interior car fiber optic lights of Jushope or other brands
Cutting pipes as you go helps preserve enough length for a secure fit without committing to a full batch of potentially mismatched pieces. If a pipe is too short to retain tension or fails to reach its lens, recut that run rather than relying on adhesive as a substitute for the intended mechanical fit.
Color changes, unused LEDs, and material notes
The MPU6050 detects when the clock is turned upside down; the project uses that movement to change the color palette. Gilbert also notes that eight LEDs remain unused and could potentially be used for an AM/PM indication in a future revision, but that is a possibility rather than a feature documented in the described build.
Rank #3
- Versatile panel-mount light pipe for use with surface-mount or through-hole LEDs
- Available in a wide range of lengths to accommodate various PCB positions
- Fits into 0.118-inch/3mm diameter light pipe holes; requires no physical connection to LED for added flexibility during assembly
- Optical-grade polycarbonate construction provides exceptional light transmission
- RoHS and REACH compliant; conflict mineral-free
Gilbert suggests matte PLA may hold the pipes better than glossy PLA, while explicitly treating the idea as a theory she planned to test further. The available project account does not establish a tested material-performance difference, so the specified black and white PLA colors are the dependable print guidance here—not a proven matte-versus-glossy rule.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What to verify before substituting parts
The instructions specify a particular LED type and matrix size, controller family, sensor module, pipe diameter, and enclosure geometry. The available project information does not establish that different parts will work without changes. Before substituting, verify:
Rank #4
- The led light guide fiber is used for creating a beautiful lighting atmosphere. Widely used for coffee house, swimming pool, home, park, etc..
- Outside diameter of the PMMA fiber optic cable is 5mm, with 1 meter or 3.3 ft length. The operating temperature range is recommended to be controlled in 0 to 180 Fahrenheit.
- The optical fiber emits bright color (light source is not included here), with good optical conductivity and flexible enough.
- Put the fiber cable into your led light gap first, then create the shape what you need.
- The light source needs to be purchased separately, here is not included.
- Controller and firmware: the replacement board must suit the sketch and its connections.
- LED matrix: check both the 8×8 layout and addressable LED type against the wiring and code.
- Light pipe: confirm 3 mm diameter, side-emitting behavior, and enough flexibility to route through the enclosure.
- Printed fit: a change in pipe or electronics dimensions may require changes to the base, slots, or holes.
Make’s project page identifies the parts and links to its build resources, but does not establish current prices, stock, seller identity, or compatibility for substitutes. Its listed $0–$50 figure is a project estimate, not a verified shopping total.
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