DIY Laser Projector From Two Old HDD

Hello everyone!

Today I am publishing a short article about how I assembled a laser projector from old hard drives. Which turned out to be not very interesting, but the sound visualizer turned out to be surprisingly amazing. If you are interested in the details, then watch the video or read the article

Two faulty hard drives from the well-known brand WD have been lying in the trash for a long time and taking up space.
And now the time has come to bring your old idea to life, to try to assemble a laser projector from them. Since the reading head of the HDD is nothing more than a galvanometer and it is just ideal for moving the mirror to a given position on one axis.

Armed with the tool, I begin to fulfill the intended goal. To do this, I first take apart the hard drives.

Next, I remove the head movement mechanism from it and remove the investment, magnetic pin.

Using a tester or visually, we find the contacts to which the conductors come from the electromagnetic coil and solder the wires to them.

To reduce the size of the device, I saw the hard drive case in two.

In order to fix the mirrors, I assemble holders for them from two brass stands and an aluminum petal.

I cut out a mirror from an aluminum disk from the same HDD. Its size is 35 x 10 mm. I glue these mirrors with cyanoacrylate glue to the galvanometer. When gluing, keep in mind that the glue sets instantly. It is better to first install the mirror in the groove, and then drop a drop of glue into the joint.

After collecting 2 galvanometers, I connect them to the corners from the window frames, at an angle of 90 °. To do this, I had to drill 2 holes in the aluminum base and fix the corners to them

I installed a Chinese laser, it is very weak and hardly visible in daylight. But for a dark room it is quite enough.

The mechanical part of the projector is assembled, now we connect its electromagnets to the PAM8610 two-channel power amplifier. I quickly wanted to test my device in action and I decided to send music to the input of the amplifiers. And lo and behold! I saw a beautiful sight, as if in an instant I found myself in a nightclub or at a concert of my favorite rock band. The result is a cool laser color music. She draws incredible pictures in time with the music, which you can look at without stopping. What is most surprising is that the resulting images are so diverse and do not repeat from track to track.

Now I try to turn it on with free software in projector mode and then I was disappointed. Without a constant component from the output of a sound card, it is impossible to display good images or animation. Since all corners are rounded through the blocking capacitors, it is not possible to hold the galvanometer in one position and it immediately tends to return to the middle position. Galvanometers also require feedback to maintain the zero point. And you also need to ensure that the beam is extinguished, that is, turn off the laser at the time of returning to the initial position. For conversion, you will need a USB sound card with at least 4 channels. I do not have an external sound card yet, and I decided to continue my experiments after it comes to me.

Free software used: ild file editor - Samogon_Laser_Editor Ild file and animation player - LFI_Player

At this point, I temporarily pause the project until the components I need are received. Since I am not a specialist in laser projectors, I expect your help in the form of consultations.

Thanks for reading my article.

If you have any questions, I will be happy to answer them.