Mohamed Dardiri took a professional looking photograph of a laser cut design he made and it was getting likes on Pinterest within minutes. You can do this, too! Photographing small projects using one of our light cubes gives you a nice, even lighting without any harsh shadows.
Archive for the ‘Projects’Category
Here’s a summary of my coffee table project that many of you have seen me work on (or struggle with) over for the last several months.
I like furniture that can flex or modify it’s position to address different needs. I’ve seen coffee tables that raise to eating height before, but I wanted to design one that really expresses the mechanism and plays up the physics behind it. Back in October I made a 1/2 scale mock up of the design to understand the motion.
Then it was back to designing a full size mock-up.
I realized it wasn’t going to be stable enough with just one set of arms, so I decided two sets would still look good. Everything was designed in Autodesk Revit. The software allows you to figure out volume, then with a given density of materials I could get weights from the various parts. This allowed me to determine the balance. I didn’t want it to be perfectly balanced with the counter-weight, but have enough weight to assist the movement.
First I started making the frame out of aluminum. It’s fastened using a pneumatic riveter.
Painting the steel arms.
CNC cutting the concrete forms out of pink foam
Creating the concrete counter-weight form
Failed attempt to CNC cut aluminum for brackets. I’ll skip the rest of these struggles…
Casting the concrete base
Casting the counterweight (nice and sloppy)
The base assembled.
Frame is attached.
There were many tweaks after testing it. There was some wiggling around the axles, so I widened the holes in the steel arms to put nylon sleeve bearings in for a tighter smoother fit. There was still some shifting after putting some weight on the front, so I designed a locking mechanism with a latch.
Lots of struggle with this latch at the top of the photo. (FYI, learn the cold metals milling machine if you need a part like this)
And finally… a video…
By Josh Myers
This Saturday, April 30th, we will meet at 9pm in the shop to discuss our entry into the Power Racing Series. Its a friendly competition between hackerspaces where we modify ride on kids toys and race them at Maker Faires. We have a car that works great but is in need of TLC. We have a race in San Mateo in a few weeks time and need to get it ready. We will be discussing what needs to be done for that race and races to come. If you have experience with welding, electronics, fabrication, you are more than welcome. If you don’t have experience, come by and get some. Read the rest of this entry →
I had a plan for how to blog about this project, but I’m going to step out of order and talk about the latest development since it pertains to the last Fusion 360 Meetup. So to catch up in a hurry: I’ve already constructed a control box containing an Arduino Mega 2560 and a Raspberry Pi, power supplies, relays, etc. all mounted on DIN rails. This is the “brains” of the system, and the Pi runs an open source control framework called EPICS. The control box sits on a separate stand on wheels that I welded. In keeping with the “Beer Church” theme, I suppose this is the “Beer Pulpit”.
I realized early on that the control box was out of room. I want this brewing system to be modular so that I can attach different equipment and reconfigure everything via software. To that end, each device needs to connect to the control box with its own sturdy, detachable connector. The original BrewTroller project (which isn’t online anymore) made use of XLR jacks. These are ideal. Nearly every device I’m interfacing with uses 3 or, in some cases, 2 wires. The OneWire serial bus, which is used for measuring temperatures, uses a 3 pin M12 connector; these are chained together using splitters. A few use cases need more than 3 wires: multiple pressure transducers on one board (used for fluid level sensors) and stepper motor drivers (used for controlling gas needle valves). For these, I’m using 8 pin mic connectors. But I don’t have enough panel space on the control box for all of these jacks, especially now that I’m considering adding a small touch screen. Nor do I have room inside the control box to mount a 120 V to 24 V transformer; 24 VAC is a HVAC standard, and the propane burner valves need it.
Last Monday, NegativeK got the funny idea that he wanted to do a project to practice his sheetmetal work. 20ga mild steel sheet was ordered, and we collected in cold metals to make some very expensive tool trays.
Once we all finished drawing lines all over our sheetmetal we had to come up with how we were going to make all the cuts.
That’s an 8″ shear. It makes cutting sheemetal a magical experience. It’s quiet, smooth, and pretty easy to control. The only thing to remember, is it’s like working with the tip of a pair of scissors. It cuts a long way in front of where you “see” it cutting, and if you reach the end of the cut, it makes a punch mark. Just… it’s steel instead of paper.
That does mean making inside cuts is a bit of a challenge. We all had unique approaches to dealing with the inside corners. Now that we have three and a half toolboxes, I think that the “best” method, would have been drilling holes at each inside corner. Instead, I twisted and wiggled out the metal, and used a file to clean up the corner.
Here’s my tool tray blank. All of the fold lines are marked, and it’s sitting on top of my tool tray handle. I didn’t get good shots of how we did the handles. They were definitely easier than the body of the tool tray. To go from that flat sheet of metal, to a three dimensional tool tray, requires a sheet metal brake.
Those folds were simple in description, but not so simple in practice. None of ours look machine made. But they do hide the sharp edges, and make the tool trays safe to use.
The handles, and sides were affixed to each other with the space’s spot welder.
Spot welding is a very quick method for joining metal. I’m glad we’ve got that tool in the space. I had suggested that we might rivet the parts together, but between drilling and attempting to rivet, we’d have spent two or three times longer affixing the parts together.
The welds also have the air of “professionally made.” Or at least “not in a garage” made.
A number of commercially available and hobbyist-built computer controlled brewing systems already exist that solve many of the issues I mentioned in my previous post on this topic. They have a number of similarities, but address the problems in different ways. I’m going to describe a number of methods used for computer controlled beer brewing, which improve up0n repeatability by reducing deviations in the mash process. These systems range from simple thermostat / standalone PID controls to microcontroller-based devices. I’ll also list my own design decisions when building this system and my reasoning. Note that my design decisions aren’t necessarily best, there are plenty of valid arguments for and against many of the solutions presented here, and as I write this, I’m kicking myself for some of the mistakes I made along the way.
I’ve examined a number of systems. Our local homebrewing store operates one. I’ve paid particular attention to open source and published plans for hobbyists, given that these offer the most information. Two of my primary sources:
- Brutus Ten – Website here. Build pages here and here. This is a popular brewing system due to plans published in Brew Your Own. It consists of a welded steel frame and propane burners driven by standalone industrial temperature control modules.
- BrewTroller – The original website was oscsys.com which features an Arduino-based open software and control electronics framework for brewing. The website hosted the software, documentation, a web forum for users, and an online store where one could purchase electronics, actuated valves, switches, temperature probes, etc. It is not locked to any single brewing system design; rather, it is flexible enough to support a wide variety of brewing hardware configurations. While the original site shut down, a user took this over at this site.
A bit over a year ago, I began a project to build a computer-controlled beer brewing system that Beer Church (Pumping Station: One’s homebrew club) could use to brew all-grain beer. I had no idea when I started this project that it would lead to visiting people from multiple countries, two synchrotron radiation sources, and a nuclear research reactor, or that control systems engineers from international labs would provide assistance. While it still isn’t ready to brew beer yet, I’ve recently reached a milestone in integration testing, and I’m rapidly approaching the point where the first test batch will be possible. Unfortunately, I haven’t been blogging about it, so a lot of catching up is needed….
So, why would someone want to make what could be called a CNC machine for beer? First, it’s not about eliminating humans. The goal isn’t automation to the level of “push button, get beer.” Humans will still need to load the ingredients and monitor the process. We don’t want a hose breaking, resulting in 12 gallons of beer wort on the floor and a propane burner melting the bottom of the resulting empty stainless steel keg. Rather, the primary reasons are:
- Repeatability. I want to eliminate human error. Repeatability often is the domain of commercial brewers, but for hobbyists, repeatability still is critical. Transitioning from good beer to great beer means experimentation. And that requires having good control over all the variables. How do I know if that different yeast I used made my beer taste better, or if it could be explained by sloppy temperature control in the mash process?
- Predictability. Shareware and free beer design software exists that acts like CAD for beer. You can design your grain bill based on a library of ingredients, enter a mash and hop schedule, yeast, fermentation temperature, etc. and it will simulate the process, telling you what you can expect in terms of initial and final specific gravity, percent alcohol, color, bitterness, etc. You can tune the model based on the efficiency of your brewing system. But prediction works only as well as the repeatability of your process.
- Capacity. Right now, we are limited to 5 gallon batch sizes. While we certainly can buy larger hardware, it makes sense to upgrade to automation at the same time. With a system based on 15.5 gallon beer kegs, we can produce 10 gallon batches at a time.
And, well, there are plenty of secondary reasons that can best be described as “Because hackerspace!” I’ve wanted to learn more about industrial control electronics and the EPICS software environment. It was a great excuse to learn to weld. I had acquired authentic cold war indicator lights from actual nuclear missile systems that needed to be put to an awesome new use. And I could do all that while brewing beer!
To describe the CNC beer system, I first need to explain all-grain brewing and the issues inherent with our current brewing method. To be clear, these issues affect repeatability, not quality. We are already making really good beer. Nothing is wrong with what we’re doing. This new system likely will improve beer clarity (and that is important in homebrewing competitions) but otherwise it won’t do much on its own to make the beer better. Start with a bad recipe and you’ll end up with bad beer; the new hardware just makes it repeatably bad! Rather, it will provide state of the art tools to anyone who wants to experiment, and this could be very useful to brewers wishing to be competitive in homebrewing contests.
The PS:One ShopBot is a great CNC machine that has the benefit, among other things, of being huge, allowing for a lot of cuts on large pieces of material. One of the difficulties working with the machine, however, is getting the bit at exactly 0,0,0 in the X, Y, and Z axis so that if you need something cut at exactly six inches from the edge of the material, it will be exactly six inches. There is already a built-in method for setting the Z axis, using a metal plate and clip and running a specific program on the ShopBot, but there is no such program for setting the X and Y, requiring the user to manually position the bit. This can lead to inaccuracies and wasted work.
To help everyone with accurate setting of the the X, Y, and Z axis, I made a thing:
This is an aluminum plate that is milled to be as precise as I could make it (read: probably a lot of room for improvement) where it sits on the lower left hand corner of the piece to be cut, with the corner of the work sitting directly in the middle of the circle.
With the piece placed on the work, the cable is plugged into the back (I had originally drilled two holes on the front left and bottom of the plate, forgetting that is where the bit has to touch so as to not push the plate off the work, so I drilled a new hold on the back and wrote “Do not use this hole” on the other two) and attached via the alligator clips (ToDo: make a better cable) to the Z plate.
The user should position the bit somewhere over the top part of the plate, where doesn’t matter. The user loads xyz-zero-finder.sbp (the code is available at this GitHub repository) into the ShopBot software and runs it. Assuming the bit is somewhere over the top, it will then slowly move the bit down until it touches the top, at which point it will move to the side (visually this appears to be moving towards the front of the machine, but in reality the side of the machine with the power switch is technically the bottom, or X axis). The program will move the bit inside the circle at what it believes is exactly 0,0,0 and, after displaying a message, will move the bit up two inches to allow the user to remove the plate and put it away.
The plate is in the drawer under the ShopBot in the Arduino box (ToDo: Make a real box for the plate). Feel free to use it and report back how it worked for you, so that we can make it better.
I want to thank Dean, Everett and Todd for giving me valuable advice about how to mill the plate on the Bridgeport; it was tricky because both sides of the plate are milled and getting it to sit properly in the vice was very worrying to me. I also want to thank Eric for suggesting the project in the first place.
Last Tuesday, we received the planer that we decided to purchase in that
vote informal action from a month or two ago. It can plane a board up to 16 inches wide, and thanks to the skewed cutting angle provided by the helical cutter head, it is far quieter than our previous planer. Last Friday and Saturday, I planned and built out the dust collection, figured out the power layout for the shop, and researched how to run a 220V line. After much reading, I decided I wasn’t competent to hack our 220V electrical system and started hunting for an electrician. On Tuesday night, after showing Eric B. what I had planned, I learned that I had already done the hard parts. Eric’s knowledge helped carry me over the finish line, and I’m happy to report that the planer is up and running! The first authorizations will be coming soon, as soon as your Wood Shop team can craft a training checklist for the machine. Here are some pictures!
Can you feel the excitement? Andrew can!
Radio control flying is traditionally done “line of sight.” That is, you stand in one place, and watch your toy fly around. Modern electronics means we can get little cameras, that hobby size aircraft can easily lift. For example, that little camera package you see there, is 17.5 grams.
My previous camera package fried when I hooked the wrong power supply up to it a few weeks ago. For the record, putting 12.6v from a LiPo battery pack, doesn’t do good things for the health of a 3.3v video transmitter.
We have some protoboard, my new transmitter, my old transmitter, the video camera, some pin headers, a JST style battery connector, a set of dip switches, and most importantly, a voltage regulator. That last bit is to stop me from frying the camera or transmitter on accident again.
In a fit of bad practice, I have no decoupling (capacitors) to support my voltage regulator. As with many things in electronics.. sometimes it works even if you do it a bit wrong. If the video signal ends up being poor, I can always add more power filtering later.
When I first fried the video transmitter, I thought it had shorted out against my quadcopters chassis. It’s not a good idea to leave power rails exposed, so there’s a good bit of hot glue on the bottom of the board.
Once that was done, I powered it up, and made sure I could change channels using the DIP switches, and that the video was clear in my goggles.
Antennas are a funny thing. Most people doing FPV use circularly polarized antennas. I didn’t have any small coax handy when I built this the first time, so I just reused my conventional antenna. That little black wire, is a full wave antenna at 5.8ghz!
Other than being twice the weight of the previous camera rig I was running, I’m quite happy with how this turned out.
Keep making stuff!
PS: If you’d like more detail on the build: http://realtinker.blogspot.com/2015/07/building-better-fpv-video-rig.html