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In this video I’m going to talk about this object here which I’ve designed in CAD, 3D printed and assembled. There are multiple parts, connected using fixings, but this is still a prototype which has already evolved from the object you can see on screen.

This is a mirror stereoscope, and if you don’t know what one is, or simply a stereoscope, I’ll briefly explain. It is a device which can be used to view a pair of 2D images, creating an illusion of depth of field or 3D depth within the image. The way that is achieved is by taking two photos of a subject with one of the images shifted slightly to one side – in the same way our eyes are offset. If you blink either eye while focusing on a subject, you’ll notice the subject will shift left and right because your eyes are effectively in two different locations. When both eyes are open your brain merges them together and you’ve got depth perception.

A mirror stereoscope is a stereoscope but with mirrors and in this case, used for some types of scientific experiments where separating the left and right visual fields is required – which is how I’ve come to be making one.

My brother who is a scientist, made something similar out of foam board. I helped him film a video about how to craft and assemble the device, but because of the type of material and techniques used, it wasn’t robust. It couldn’t be transported easily, and over multiple uses could become damaged and needing repair. I decided to make one that could be 3D printed and was a little more durable, and because I didn’t get paid to do it, that’s why it’s pink.

I’ll describe the object and its parts. In the centre are a pair of mirrors set at 90 degrees and to either side are pivoting mirrors. You would normally position your head roughly here, and those pivoting mirrors can be used to align the gaze of either eye, so the subject appears hole and complete to the viewer, despite the vision being split by the mechanism of the stereoscope.

This model has a few novel features that I’ve added to expand on the foamboard version. These includes fine adjustments screws for the pivoting mirrors, a quick release divot for a mobile phone clamp which is used to hold the stereoscope in position, an extendable fin for further splitting the vision, and finally openings for small bulldog style clamps to hold the mirrors in place and remove the need for adhesives.

I’ve also tried to design this with a minimum variation of machine screw lengths.  There are roughly 25@ m3x30, and 4@ m3x20 machine screws for the main body assembly. The pivoting mechanism uses slightly lager M4 fixings.

I’ll talk a little about the pivoting mechanisms now. These are made up of longer m4 machine screws which pass through barrel nuts that are housed to the stereoscopes body. Those longer screws will be connected to a shorter M4x30 machine screw assemblies, which slots into a 3d printed joint that’ll be attached to the back of the pivoting mirrors.

The head of the machine screw and first washer need to be small enough to fit into the 3d printed joint.

The m4x30 assemblies includes the machine screw, with a washer, a 3d printed semicircle, another washer and a locking-nut. On screen I have a m4 nut locking a stud connector onto a machine screw.  

That assembly is connected as mentioned to the longer machine screw which passes through the barrel nut. Because the barrel nut is fixed to the stereoscopes body, when the screw is turned, it moves through the nut but because it’s a barrel it can also pivot. When the adjustment screws are turned clockwise the washer next the locking nut pushes against the 3d printed joint mechanism and the mirrors move forward. When they are turned anti-clockwise, the mirrors are pulled and thus pivot backwards.

There are some other features too. The wedge at the bottom is a divot clamping location for an off the shelf mafrotto mobile phone clamp. I originally designed this feature for a camera lucida that I made so I wouldn’t have to embed a tripod mounting thread into the plastic. The phone clamp has mounting threads which can be attached to a tripod plate, and eventually a tripod or clamping arm.

I want to replace a few sections on this model, before I can pass it onto my brother to use and test.

At the rear of the mirror stereoscope is a fixed screen divider fin – protruding outwards and designed to prevent accidental cross contamination between the left and right fields of vision. I’ve redesigned this part to include slots – so it can be pulled out if necessary.

The other difference from the one on screen now, are the two top plates will have openings for clips to hold the mirrors. I didn’t want to glue the mirrors on as this is not a final design, but I’ve come to realise it’s worthwhile making with the intent of dismantling and reversing the process, for as long as possible. Use glue as a last resort, as the more glue you use, the more you’ll have to throw away if something goes wrong.

Anyway, I ran out of pink printer filament so I’m using this pastel green stuff for the last bits.

After dismantling the parts I want to replace, I begin by gluing the pivoting joints.

My super glue bottles nib got stuck onto the inside of the lid, so I’m using cotton buds as applicators. I’ve also put down some green card just in case I spill any glue onto my nice kitchen table.

Once those were glued in place, I could connect the m4 stud connector onto the shorter threaded machine screw. I was initially going to try lock this in place with a nut, but I decided to dab a little glue on the thread and screwed the connector about halfway instead – making a permanent connection. I waited for that to set before gluing and screwing the opposite ends.

And after that was all was complete, the glue nozzle magically reattached back onto the bottle.

I normally keep it in a little bag, and in the fridge and I’ve had this open for a month and it has not dried. I can show you the mechanism now and it’s working really well now. And all it needed was the connector piece there. I will reposition these roughly in the centre and attach the top section

I’m now attaching the new top sections, with the openings. Starting with the pivot mount which has a washer between the two sections. There is washer between the top and bottom just to help prevent the piece dragging when it is moved.

After which, I carefully replace all the fixings, followed by the new screen divider.

I clean and replace the mirrors, which are now held discreetly with bulldog clips from the top.

I can also test suspending the stereoscope on the clamping arm – which works as intended.

Now you probably think this video is more or less over, but I’d like to briefly talk about the 3D printing process. I used a Prusa i3 mk3s+ for the bulk of the work, but later realised I could print all the parts on my Prusa mini as well. Everything printed flat without supports apart from two sections – the fixed mirror mount and the pivot joints which needed support for the overhangs. I used the 0.20mm quality print settings – with a rectilinear infill pattern of 15%. I used brims for some parts but later realised I didn’t have too.

Total printing time of all the parts was roughly 41 hours and 17 minutes which doesn’t include setup and removal times. Of course, splitting the jobs across two printers would help dramatically reduce that duration. All the printed parts used roughly 588 grams of filament, and I used PLA to make the.

So the professor got back to me with the thumbs up – so I’ll link to my online shop where you can by the project files from this 3D printed mirror stereoscope. The only feed-back I got from my brother was that they used some black card over the pivoting mirrors to help focus the gaze of the participants. In reality dark grey or black PLA would help concentrate the view and lighting towards the subject – a bit like how theatres and cinemas are shrouded in darkness. Anyway that’s it for me, thanks again for watching and you’ll see me in the next one – whenever that will be.