Hackaday Links: September 15, 2019

It’s probably one of the first lessons learned by new drivers: if you see a big, red fire truck parked by the side of the road, don’t run into it. Such a lesson appears not to have been in the Tesla Autopilot’s driver education curriculum, though – a Tesla Model S managed to ram into the rear of a fire truck parked at the scene of an accident on a southern California freeway. Crash analysis reveals that the Tesla was on Autopilot and following another vehicle; the driver of the lead vehicle noticed the obstruction and changed lanes. Apparently the Tesla reacted to that by speeding up, but failed to notice the stationary fire truck. One would think that the person driving the car would have stepped in to control the vehicle, but alas. Aside from beating up on Tesla, whose AutoPilot feature seems intent on keeping the market for batteries from junked vehicles fully stocked, this just points out how far engineers have to go before self-driving vehicles are as safe as even the worst human drivers.

The tech press is abuzz today with stories about potential union-busting at Kickstarter. Back in March, Kickstarter employees announced their intent to organize under the Office and Professional Employees International Union (OPEIU). On Thursday, two of the union organizers were fired. Clarissa Redwine, who recently hosted a Hack Chat, was one of those released; both she and Taylor Moore are protesting their terminations as an illegal attempt to intimidate Kickstarter employees and keep them from voting for the union. For their part, Kickstarter management says that both employees and two more were released as a result of documented performance issues during the normal review cycle, and that fourteen employees who are in favor of the union were given raises during this cycle, with three of them having been promoted. There will no doubt be plenty more news about this to come.

Would you pay $900 for a Nixie clock? We wouldn’t, but if you choose to buy into Millclock’s high-end timepiece, it may help soften the blow if you think about it being an investment in the future of Nixie tubes. You see, Millclock isn’t just putting together an overpriced clock that uses surplus Russian Nixies – they’re actually making brand new tubes. Techmoan recently reviewed the new clock and learned that the ZIN18 tubes are not coming from Czech Republic-based Dalibor Farný, but rather are being manufactured in-house. That’s exciting news for Nixie builders everywhere; while Dalibor’s tubes are high-quality products, it can’t hurt to have a little competition in the market. Nixies as a growth industry in 2019 – who’da thunk it?

We ran across an interesting project on Hackaday.io the other day, one that qualifies as a true hack. How much house can you afford? A simple question, but the answer can be very difficult to arrive at with the certainty needed to sign papers that put you on the hook for the next 30 years. Mike Ferarra and his son decided to answer this question – in a circuit simulator? As it turns out, circuit simulators are great at solving the kinds of non-linear simultaneous equations needed to factor in principle, interest, insurance, taxes, wages, and a host of other inflows and outflows. Current sources represent money in, current sinks money paid out. Whatever is left is what you can afford. Is this how Kirchoff bought his house?

And finally, is your parts inventory a bit of a mystery? Nikhil Dabas decided that rather than trying to remember what he had and risk duplicating orders, he’d build an application to do it for him. Called WhatDidIBuy, it does exactly what you’d think; it scrapes the order history pages of sites like Adafruit, Digi-Key, and Mouser and compiles a list of your orders as CSV files. It’s only semi-automated, leaving the login process to the user, but something like this could save a ton of time. And it’s modular, so adding support for new suppliers is a simple as writing a new scraper. Forgot what you ordered from McMaster, eBay, or even Amazon? Now there’s an app for that.

Hacking The Tesla Model S Rear Drive Unit

[Jason Hughes] is a big fan of Tesla, he’s spent a lot of time hacking on them to figure out what fancy things the automaker is up to. His most recent adventures are with the rear drive unit of a Tesla Model S.

[Jason] has had some fame in the Tesla community before; his most publicized hack was finding the model number for Tesla’s next edition of their car hashed away in the firmware. For this project he procured a rear drive unit from… somewhere, and with some help got it onto his bench at home.

His first steps were to hook it up to some power and start sniffing the CAN bus for commands. It took him a few hours but he was able to get the motor turning. He kept working at it until he had the full set of commands. So, he hooked up circulating water to the unit for cooling, and put it through its paces (at one point the unit announced it was now traveling at 117mph).

In the end he was able to get all the features working, including generation! He even made his own board for contrl. Just listening to the motor spin up is satisfying. Videos after the break.

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Tesla Model S Battery Teardown

Tesla Motors club user [wk057], a Tesla model S owner himself, wants to build an awesome solar storage system. He’s purchased a battery pack from a salvaged Tesla Model S, and is tearing it down. Thankfully he’s posting pictures for everyone to follow along at home. The closest thing we’ve seen to this was [Charles] tearing into a Ford Fusion battery. While the Ford battery is NiMH, the Tesla is a completely different animal. Comprised of over 7000 individual lithium-ion cells in 16 modules, the Tesla battery pack packs a punch. It’s rated capacity is 85kWh at 400VDC.

[wk057] found each cell connected by a thin wire to the module buses. These wires act as cell level fuses, contributing to the overall safety of the pack. He also found the water cooling loops were still charged with coolant, under a bit of pressure. [wk057] scanned and uploaded high res images of the Tesla battery management system PCBs (large image link). It is a bit difficult to read the individual part numbers due the conformal coating on the boards.

A second forum link shows images of [wk057] pulling the modules out of the pack. To do this he had to chip away the pack’s spine, which consisted of a 2/0 gauge wire potted in some sort of RTV rubber compound.

We’re sure Tesla doesn’t support hackers using their packs to power houses. Ironically this is exactly the sort of thing Elon Musk is working on over at Solar City.

Tesla Model S Handle Dispenses Beer; Hides When Done

tesla-model-s-beer-dispenser

Let’s face it, sometimes you need to take time out from engineering cutting-edge electric vehicles to over-engineer a beer fridge. And to tell you the truth, after seeing what [Matt Brown] managed to pull off we now have a gut-felt yearning for one of our own. He took a beer fridge and added a vanishing dispenser handle from a Tesla Model S.

You might be thinking that this an expensive part, and you’ve be more correct than you realize. It’s not even a stock part. This is a prototype that someone threw in the trash. [Matt] plucked it from oblivion and milled a spot for it in the door of the fridge. Your average [Joe] probably doesn’t know that the Model S comes with handles that pull themselves flush with the body of the vehicle.

[Matt] dug out insulation on the inside of the door until there was room to cut a hole for the handle. The clamped the assembly in place and used spray foam to re-insulate as well as glue it in place. An Arduino monitors the area below the tap. When you put your glass under the spout the handle extends. When you pull on it a solenoid drives the tap handle forward. This sounds pretty dry, but we think the demo after the break will have you lusting after one as well.

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