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Vinten Tripod Leg Lock

I was doing a video shoot with Ben Nelson for Brown Dog Gadgets last week and I noticed his Vinten tripod leg had an issue staying locked in place… Seems one of the leg lock pieces had broke in half. It seemed liked a perfect reason to fire up OpenSCAD and get the 3D printer spitting out a new part.

In the photo above you can see the new part in silver, and the two original parts on the other legs, in black.

It took two prints to get an acceptable fit. The first was a little too wide and wouldn’t quite fit in place. I tweaked the file just a bit and the second version worked well. I’ll walk through the process a bit below.

For an organic shape like this I usually start by putting it on a desktop scanner to get the profile. This one is curvy, and I’m not big on drawing curves in OpenSCAD, but I am big on scanning in an object and then tracing it in Inkscape. I did a few scans and even then I edited the image a bit to adjust the contrast.

I import the images into Inkscape, each layered directly on top of each other, then add another layer on top of that to do the drawing. I can then easily switch out the image below and compare things. For a symmetrical drawing like this I really just need to draw half of it, then I just dupe and flip to make the other half and combine them into one.

Once I have a vector file created I export that and then import it into an OpenSCAD file where I can extrude it changing it from a 2D shape to a 3D shape. Creating a solid object is the goal. Once I’ve got a solid object I can start knocking holes in it and adding angles by subtracting with various shapes. (The reddish parts are all subtractions or differences from the main piece.)

And yes, the above image does appear to be some sort of special forces TIE Fighter from the Star Wars universe.

Here’s our final piece, ready to be rendered, sliced, and printed. The original part had some pockets on the top and bottom, but since they were not required for functionality I left them out.

Ben installed it and briefly tested it and it seemed to work, though time will tell if it holds up under stress. (Also, this one is PLA so if he leaves the tripod in a hot car, it might soften and fail.) I’ll probably print a few more for him to keep in the tripod bag in case this one does fail in the field.

If you want to print one of these, you can grab the file from Vinten Tripod Leg Lock and have fun!

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Hot Glue Gun Repair

Glue Gun Repair

I spent some time after class in the Physical Computing Lab repairing the hot glue guns. During class students told me that the triggers didn’t seem to work, and they had to push the glue into the gun by hand to get anything out the hot-end.

I removed all the screws (about 8 of them) and opened one up and it’s a lot of plastic inside, besides the hot bits. There’s a plastic piece that snapped, due to (I’m assuming) pulling the trigger too hard. It’s a poor design, but I was able to repair it by drilling holes in the two pieces and adding some wire through the holes and twisting it tight. This was enough to pull the pieces close together. (I contemplated using cyanoacrylate, but didn’t have any, and wasn’t convinced it would work.)

Glue Gun Repair

Two of the guns were in good condition, except for the snapped piece of plastic, but the third one must have been repaired before, because the rubber retaining ring and a tiny spring were missing, and the larger spring had been replaced by a not-quite correct replacement spring. The third one (once assembled) didn’t do a very good job of pushing the glue forward. I may have to try further repairs, but at least we have two working better now.

Glue Gun Repair

The other issue, which may have cause some of the problems, is a “HIGH/LOW” switch on the handle. When I held the gun, I ended up switching it to LOW. If someone had been using it on HIGH and accidentally switched it to LOW, they might have kept pressing hard on the trigger while the temperature dropped, and snapped the plastic bit inside.

Glue Gun Repair

I added some tape to the switches so they don’t get accidentally set to LOW. We only have high temperature glue anyway…

Glue Gun Repair

The third gun, which doesn’t work very well, got labeled “Not Great” so we remember which one is the crappy one., which can still be used, as long as you don’t mind (possibly) pushing the glue forward with your hand.

Glue Gun Repair

Reminder: Hot Glue is Hot!

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Garage Fix (At Last!)

Beam Emitter

Since we move into our house nearly 18 months ago we’ve been dealing with the super-annoying “sometimes it works” garage door opener. Or perhaps “garage door closer” is more accurate. In the olden days garage doors just closed, and if you got crushed it was your own damn fault. Somewhere along the way (in the name of “safety”) manufacturers added “External Entrapment Protection Systems”, which are typically an infrared emitter and an electric eye that sees the beam from the emitter. When the beam is interrupted (like when a stupid child runs under the closing garage door) the door reverses and does not close. No child crushed, no harsh lessons in being careless learned.

Look, I’m not in favor of crushing children, but with the sun shining directly at our garage opening, 75% of the morning we’d leave the house we couldn’t use the remote to close the garage door. I didn’t want to completely disable the sensors, as it would probably get us sued if a child did get crushed. Also, I’m all for safety. (Really. I am. Tell the insurance company that.)

My first attempt at a fix was adding a gaff tape flag to the electric eye. This did almost nothing. I did find that blocking the sun with my car and/or body sometimes worked. So imagine that when I pulled the car out of the garage I had to get out and stand in front of the door (very close to it, in fact, almost close enough to be hit by the door) and try to block the sun. Sometimes it worked, and often it did not. When it didn’t work we’d have to go into the garage, use the manual release to shut the door, lock it, and then reverse the whole procedure when returning home. #PITA

Eventually I added a button (duh!) to attempt to manually override the sensor. Sometimes it worked, other times it did not. Occasionally it would get 90% closed, then open again. Argh! Reflecting light? I don’t know…

Electric Eye

Supposedly you can added some tubes, but I never got around to that. The garage not closing when you leave is just annoying enough to aggravate you, but not annoying enough to spend real time trying to fix it.

The new solution (which is working well so far) involves extending the electric eye a bit further in from the door, and angling it to point at the emitter. Some scrap wood and zip ties pulls it all together quite nicely.

New Garage Beam Layout

Here’s our new set-up. Granted, there is a bit more room where something could get crushed, but it probably won’t be me, because now I don’t need to stand Centimeters from the door as it’s closing.

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Little Cars / Big Cars

Car Repair

Disclaimer: I’m not really much of a car guy. I mean, I own a car, but I’ve never been into repair and maintenance of them. Probably because when I was in high school there were “gearheads” (people totally into cars) and I just didn’t get it. I’ve mostly considered cars as a means to get from point A to point B. I’m more concerned about being able to haul things than I am about doing it in some super-powerful manner or even looking good doing it.

While I’m still not really into “regular” cars, I’ve had a good time being involved with the Power Racing Series, where we modify children’s toys and race them. Milwaukee has had a team since the start, and I’ve been involved for three seasons now. It really is a combination of serious fun and serious engineering, and if there’s one thing I’ve learned, it’s that repairing a car body by drilling holes in the plastic and connecting pieces with zip ties is the right way to do it.

Zip Ties

Yup, totally serious. That’s how I repaired my wife’s car this past weekend. Drilled holes, connecting pieces with zip ties. Done. (And yeah, this isn’t the first time I’ve repaired this car with zip ties!)

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Fixing the Fixture

Adapter

I (somewhat) jokingly posted something the other day about how my wife asked me to 3D print something, and was totally serious this time and not sarcastic about it. To be fair, she’s heard me say “I’ll just 3D print one!” about 100 times this summer, and was probably sick of it, but when you live in the future, it’s pretty damn exciting.

Or story begins back in 2009 when we moved into our current house. The light above the front door was just a bare bulb, with nothing around it. I’m assuming there was a glass ball at one point, and it must have broke, or been stolen, or dematerialized. No matter, we can fix it.

3D Printed Part

While at Home Depot the wife found a cheapie plastic majigger that would fit over the light bulb, so we bought it. This is also when she suggested I could “make it work” and thus, I agreed.

I ended up using OpenSCAD to design a simple ring that would press-fit the new piece, and have the needed holes to fix the fixture… and adapter, if you will.

It fits!

It worked! As you may notice, there are no mounting holes. I often don’t bother making holes in the objects I print because I’ve got a drill press, and it makes much more precise holes than the RepRaster 5000 can. (And just to be clear, the clear piece is not what I printed. I printed the black piece. Got it?)

Holes for screws

Here’s the piece after I drilled the holes and secure it into the fixture with two small bolts. Sadly the small bolts are a little long, and stick out the top, but hey, it’s still an improvement.

Fixed!

So now on the front of the house is this lovely cheapie plastic majigger instead of just a bare light bulb. Home Improvements FTW!

This is one more thing where I really don’t know how I could have done this as elegantly without a 3D printer. Using open source software I designed the needed adapter and then printed it out using open source hardware, and the total cost of materials (ABS plastic) was probably less than 50 cents. As I said… living in the future and all that.