LASERTEXT: PORTABLE LASER TEXT PROJECTOR BUILT FROM A SCRAPPED HARD DRIVE MOTOR
A scrapped hard drive motor spins twelve angled mirrors past a laser diode, and your eye assembles the flashes into readable text 27 metres away.
DisplaysWorkshop
Built withArduino3D printing
- difficulty
- ●●●●○
- time
- a weekend-plus
- license
- license not specified
- repo
- repo ACTIVE26 stars
●●●●○ · a weekend-plus · license not specified · 26 stars · repo ACTIVE
WHAT YOU’LL NEED
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COMPAREE VERDICT
LaserText is a one-line text projector that proves persistence of vision can turn a spinning mirror and a fast-switching laser into readable output at surprising range. You salvage the brushless motor from an old hard drive, 3D-print a drum that holds twelve mirrors at slightly different angles, press a 520 nm laser diode into a heat-sinked housing, and let an Arduino Nano switch the diode on and off in roughly a microsecond per pixel. The outdoor test reached 90 feet clearly; indoors at 20 feet it is brighter still. The challenge is alignment: each mirror must be angled correctly, the laser beam must hit the drum where intended, and the per-mirror timing offsets must be dialled in so the text does not skew or flicker. The repository gives you the CAD and the code but no step-by-step guide and no part numbers, so expect to spend time searching for a suitable laser module, a matching constant-current driver, and a motor driver that will spin the hard drive motor steadily. The author says the v1.0 code has a lot of issues and points to his v1.1 repository. If you have built optomechanical projects before and you are comfortable iterating on alignment, this is a brilliant demonstration piece. If you have not, the lack of a BOM and the fiddly optics will eat your weekend before you see a single letter.
IN THE REPO
GOOD TO KNOW
- —Fusion 360 and STEP files for the mirror drum, shell and laser housing are in the repo.
- —No bill of materials. The README only mentions an Arduino Nano and a Bluetooth module; the laser, driver, spindle controller and power supply are described in the video, not listed with part numbers.
- —No formal build instructions. The README is a single-page summary; the video demonstrates the assembly but does not list part numbers or suppliers.
- —The Arduino sketch is present. The author recommends the newer v1.1 repository for improved firmware.
- —No licence file in the repository. Use and redistribution terms are not stated.
Parts to buy
10 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
- Dead hard drive (for the brushless spindle motor)Find
- 520 nm direct-diode laser in a copper/aluminium housingFind
- LM317-style constant-current driver switched by a MOSFETFind
- Arduino NanoFind
- Arduino Bluetooth serial moduleFind
- Brushless motor driver boardFind
- Two slotted photo-transistor sensors for mirror timingFind
- 8× AA battery holderFind
- Twelve small mirrorsFind
- Miscellaneous wire and connectorsFind
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
Videos
DIY Laser Projector - Built from an old hard drive
Ben's own build video, linked from the README, shows the projector being designed, assembled and tested outdoors.
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Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the README on the v1.0 repository (The author recommends the v1.1 repo for improved firmware; check both before you buy parts)
- 2.Source a dead 3.5-inch hard drive and confirm the spindle motor spins freely(Check the motor against the Fusion 360 file — the shell is modelled around the drive motor used in the video)
- 3.Find a 520 nm direct-diode laser module (the author went above 120 mW) with a constant-current driver; avoid DPSS modules (they need warm-up time)(The first prototype used a 5 mW module (too dim) and a 120 mW DPSS module (too slow to switch); the final build uses a 520 nm direct diode)
- 4.Print the mirror drum, check the balance, and glue twelve small front-surface mirrors into the pockets at the angles shown in the CAD(If the drum is out of balance it will vibrate and blur the text)
- 5.Upload the Arduino sketch, pair the HC-05 Bluetooth module, and test the laser switching before you mount the drum(Use Serial Bluetooth Terminal or equivalent to send test strings)
Resources
Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.
KNOWN ISSUES
- There is no bill of materials and no part numbers. You will spend hours searching for a laser module that meets the specs (direct diode, 520 nm, more than 120 mW, fast switching) and building a constant-current driver (the author used an LM317 circuit switched by a MOSFET). Keep stray capacitors out of the laser circuit: the author killed three diodes before finding an unnecessary capacitor that dumped a current spike into them at switch-on.
- The mirrors must be small front-surface mirrors, not ordinary glass mirrors (which have the reflective coating on the back). The wrong type will double the beam and ruin the text.
- The mirror drum must be printed with care—if it is out of balance or the pockets are not evenly spaced, the text will wobble or tear. A wobbly print is not rescuable.
- Alignment is fiddly: the laser beam must hit the centre of the spinning drum, and each mirror must be angled correctly relative to the rotation axis. The README does not give you a jig or a procedure; you iterate by eye.
- The hard drive motor runs on 12 V and the laser drops 5.7 V, so the 8× AA pack (12 V nominal) is barely enough. If your batteries sag under load the motor will stall or the laser will dim.
- The repository has no licence file. Use and redistribution terms are not stated, so you cannot assume permission for commercial use or derivative works.
Can I use a different laser colour?
Yes, but green (520–532 nm) is the brightest to the human eye at the same power, which is why the author chose it. Red or blue will work but will look dimmer at the same wattage, and you will lose throw distance.
Why does it only project one line?
Each of the twelve mirrors is tilted at a slightly different angle, so each one draws one horizontal scan line; together they make a single row of text twelve pixels tall. More rows of text would need more mirrors or a different drum, which this design does not include. The author's v1.1 repository has improved code, but check it yourself for what it adds.
Do I need laser safety glasses?
Yes, absolutely. The final build uses a 520 nm direct diode that is more powerful than the 120 mW module the author first tried, which puts it in Class 3B territory: direct or specular exposure can permanently damage your retina. Wear glasses rated for the wavelength (OD 4+ at 520 nm) whenever the device is on. This is not optional.
Can I use a laptop hard drive motor instead of a 3.5-inch desktop drive?
The CAD is built around the motor Ben salvaged in the video. A laptop drive motor may spin fast enough, but its mounting holes and controller may not match, and you will have to redesign the shell. Measure your motor against the Fusion 360 file before printing.
How far can it actually project?
The author tested 90 feet (27.4 m) outdoors at night onto a fence and reported clear readability. Indoors at 20 feet it was brighter. Practical range depends on ambient light: in daylight the text will wash out much sooner.
Community builds
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Discussion1
FROM THE COMPAREE TEAM
One laser, a spinning mirror built from an old hard drive, and text drawn in the air — and the repository has no licence file. If you built this, what did you use for the laser module, and did you test it indoors or out?
Ben Makes Everything
Ben Makes Everything is a maker who documents builds that upcycle salvaged components into working projects. LaserText was published as version 1.0 in the linked repository; the author has since released a v1.1 repository with improved firmware and recommends builders start there.
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DISCLAIMER
- Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
- Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
- Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
CompareeTEAM1mo agoedited
Practical notes from our verification: the repository has no licence file, so use terms are not stated. It contains the Arduino sketch plus the Fusion 360 and STEP models, and the README is a short note covering only the Arduino Nano, per-mirror alignment offsets and the optional Bluetooth module — there is no parts list, so the rest of the hardware has to be taken from the video, where the spinning mirror is built from an old hard drive. The author says this v1.0 code has a lot of issues and recommends the newer lasertext_v1-1 repository, so check both before you start. If you have built laser projects before, the challenge is time, not difficulty; if you have not, expect a weekend lost to sourcing and another one getting the mirrors aligned. Use eye protection when testing any laser. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.