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How I learned to Stop Hating Hardware Design

Since I first started building custom pieces of hardware I’ve always been limited to a select few materials and design processes. Generally something already made would have to be cut down, sanded, or drilled with the only three power tools I own: a dremel, drill, and angle grinder. If I had to build it from scratch it most likely be made from Shapelock, before be cut down, sanded, or drilled. In the end you have a very labor intensive, not easily repeatable, struggle to build even the most simple objects (take a look at my scoring machine for example). Today that changed.

Our school has a FabLab with several different prototyping machines that are open to any students interested in learning how to use them. Among them is a laser cutter. I love this laser cutter. I took an online laser safety course a few months ago but never really pursued it further. In fact, yesterday was the first time I actually stepped foot inside the FabLab, and I’m glad I did. I was given a very brief overview of how to set up and use the basic features of the laser cutter, after that the attendant had me cut out a simple square with my initials rasterized in the middle and I was done.

I wasn’t really sure how one goes about designing something like a chassis from scratch but I went with my gut feelings, design preferences, and a general idea of what was good and what was bad. I sat down with a blank sheet of paper and slowly measured out the various dimensions I needed from different components until I had a decent 2D representation of each with appropriate measurements. I then drew a 10cm x 10cm square and slowly started drawing in components till I had something that looked like a halfway decent chassis. I went over to the Lab right after class and sat down in front of Solidworks with a very rough sketch and dimensions I wasn’t entirely sure of and started to draw my template. 20 minutes later I had something that resembled something made by someone who might know what they were doing so I stuck with it. I dug a 1/4″ piece of acrylic out of the scrap bin, measured out an area to make sure my design would fit, crossed my fingers and hit the print key. It took about a minute to cut out the entire piece and the whole time I was waiting for something to go wrong. Nothing did. I lifted the cover and gently removed my first machined chassis. I then ran back to my loft so I could check and see whether or not my measurements were accurate and parts would fit. To my great surprise, everything turned out better than expected. Take a look at some of the photos below:

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The next update probably won’t be for a while. I have to run out to Home Depot to buy some fasteners to actually attach parts to the chassis as I have none. However, there is much more to come!

 

Somehow It Works

Whenever I sit down for a while to work on a project I’ll end up getting a little obessive. This has its pros and cons but usually ends up working out in the end, save some efficiency. I posted a while back about my first PCB and promised to do a quick update once the remaining components arrived (which they have), so here it is.

In retrospect, I probably should have spent a little more time checking over the board and connections before uploading my files to OSH Park. Past experience has shown me that very rarely will things work right the first time you do them. This project was no exception. The remaining board components arrived a few days ago and I quickly soldered everything in. I tried uploading a program however ended up with a very general avr error that really offered no insight into what was going wrong. I spent a couple hours browsing through forum posts hoping to find some explanation but came up empty handed. The following day I brought the board into one of our labs so I could actually check and see if data was being sent or received through the ATmega. A couple of scope frames later I was able to see that there was communication between the RX and TX on the chip and the FTDI adapter I was using. I rechecked my schematic and everything else looked correctly connected. It then dawned on me that my RX/TX lines might be inverted (which they were). Some ribbon cable and dremeling later I was able to swap the two lines and upload a blink test.

The following day the motors and reflectance array arrived, which I quickly tested to make sure everything else still worked. I cut off a piece of cardboard from one of the boxes I had laying around and mounted the two motors in along with some hot glue to hold the board just so I could see it drive around. My plan is to laser cut a chassis once I have a little more free time, but in the mean time here are some photos and a video:

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Decorating My Room

I’d generally describe my design tastes as minimalist/industrialist so buying something extraneous to put in my room was a first for me. Part of my decision to buy what I did was practical, the one light in my room simply isn’t bright enough, but I also thought it was something fun that I could always incorporate into a project if I got bored. With very little background research and information I spent $40 on a 5m LED light strip and audio controller. It was one of the best decisions I ever made.

The parts I ordered can be found here and here. I’ve only had it installed for a week but so far I’ve been pretty impressed. The audio response works pretty well (watch the video below), and the lights also work great to supplement my one room light. I ordered a second strip to fill up more of the ceiling so I’ll definitely be making another post on this in the future. Check out a video of them in action below:

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