Category Archive

Uncategorized

Deep Dish, 1lb Plastic Melty Brain!

Posted on June 16, 2023 by admin

Over the past week I built a lil 1lb melty for a low-key local plastic ant competition. I have tried several times before to build melty brain robots, but never had the greatest luck. Now armed with many more years of breaking stuff robot experience, it was time to try again. I’ve always found the biggest problem with melty brain robots to be keeping the rapidly spinning robot synchronized to the rest of the world. Most melty brains have used an IMU sensing centrifugal acceleration to calculate velocity, and then integrated velocity to get position. This works ok, but because

0

Turning on the Camry Booster

Posted on January 23, 2022 by admin

Ain’t nuthin better than getting a hunk o’ junk on Ebay and turning it on, and even better: making it do something useful. The original plan for the Big Dyno was to use a Prius inductor– based buck converter. However, the good ole Prius inductor proved just barely not quite up for the task, with a saturation current of around 175A. Practically, this means it is only good for about 150A of boosting, and I was really hoping for the full 200A (although I will use that quite rarely, it is a nice-to-have for sure). I was able to find

0

I bought a camera!!

Posted on December 16, 2021 by admin

Big life update: I bought a camera. I’ve wanted to buy a nice DSLR for literally 5 years or so, but only now with some side consulting could I justify shelling out the cash. Turns out, my great grandfather was a professional photographer. So, camera time… I knew I would be using this camera for product photography on a near-daily basis, so I decided to go for a nice camera right off the block rather than putzing around with an APS-C with the plan to upgrade. All of my friends have Nikon’s so I chose to stick with them so

0

Saturating the Prius Inductor

Posted on December 15, 2021 by admin

The good ole’ 2nd gen Prius boost inductor. Extra large, extra cheap. I was unable to find a measurement of the saturation current of this inductor on the internet, so I set out to measure it myself. This inductor is one of the beefiest I’ve ever set my eyes upon, at about 400uH, and I estimated it had a saturation current somewhere between 150 and 200 amps. I measured the line-to-line resistance at 19 milliohms. At 150 amps, this equates to over 400W of resistive losses alone. I plan on using this inductor for the big dyno, where it will

0

Quantifying a Motor: the IPM Dyno

Posted on December 9, 2021 by admin

The land of motor ratings is pretty dubious. All too often, people say, “yes, this motor has a stall torque of 11.8 Nm and a no-load speed of 16krpm- therefore this motor produces TWENTY THOUSAND WATTS.” Alright then… But did you actually measure that? How do we even measure power of a motor in the first place? What even is power? Let’s get into the physics… An electric motor is a device which converts electrical power into mechanical power, usually through a magnetic field. The same device is also a generator, when the flow of power is reversed and the

0

Big Dyno: The Beginnings

Posted on October 31, 2021 by admin

The successor to the small dyno: the big dyno. This dyno should be good for around 30 Nm continuous up to 8-10K RPM, and then around 20-30kW from there. It is a lot of dyno.. should be excellent. This size of dyno was inspired by Ben and Bayley’s big dyno. Finding myself in need of a more powerful dyno to test ever larger motors, it was time to build my own. Here is the CAD as it stands. The dyno is largely based around an altermotter paired with an HBM 100Nm 20,000 RPM digital output torque sensor. Interestingly enough, the

0

Tesla Model S A/C Compressor Teardown

Posted on October 9, 2021 by admin

Over the past four years, automotive hybrid air conditioners have been a wonderful source for rotors and stators. All the automotive components are automotive quality, yet purchasable at junkyard prices. So far, all the air conditioners we’ve dissasembled have been of the IPM variety. We’re not exactly sure why, but we believe this is because the magnets can be straight instead of curved, reducing magnet costs. Additionally, the rotor can be constructed using less magnet per unit torque, again reducing cost. Either way, IPMs are cool, so let’s get started. So far, I’ve disassembled four different air conditioner units, all

0

Record speed motor drive layout

Posted on December 2, 2020 by admin

Today I laid out a board in record time: 2.5 hours! And, its even a motor drive! However, I did cheat a bit and use a daughter board. My work was throwing out several DRV8305 evaluation boards, which are more or less the same as the lovely DRV8323RS TI motor driver we’ve all come to love. The “throwing out several” part is important, because if I blow up the power stage, I can simply swap my daughter board with minimal effort.. The evaluation board in question: My daughter board design: At the heart of the design is the new STM32G431

0

Austinshop Pt. 8: Dolly for the Surface Grinder

Posted on November 30, 2020 by admin

Not much in this post, but its definitely worth mentioning if any readers care to make dollys for their machine tools. A core tenet of the austinshop final plan is to have the surface grinder on wheels such that it can be wheeled outside to use, to protect the shop from being covered in grinding dust. To do this I need some way of wheeling it. And the surface grinder isn’t light, so it needs to be extremely strong. I started with the door bits because they are nice, strong wood about the right size (read later post to see

0

Austinshop Pt. 6: New roof

Posted on November 30, 2020 by admin

A post which is kind of a cop-out because I wasn’t the one who put in the effort, but it’s worth mentioning. The tarp mentioned in part 2 was not a permanent solution. A more permanent solution can be purchased with money: having some dudes come over and re-shingle the roof. We got a few quotes and went with the best one. The dudes showed up right after a huge snow, so the first step was shoveling the garage. Then they got to work. It was pretty insane watching them go- these guys were roofing machines. One kind of interesting

0