Updating A 1999 Saab With An Arduino

August 11, 2018 by Tom Nardi 47 Comments

Unless your car is fresh off the lot, you’ve probably had the experience of riding in a newer car and seeing some feature or function that triggered a little pang of jealousy. It probably wasn’t enough for you to run out and sign yourself up for a new car loan (which is what the manufacturer was hoping for), but it was definitely something you wished your older model vehicle had. But why get jealous when you can get even?

[Saabman] wished his 1999 Saab 9-5 had the feature where a quick tap of the turn signal lever would trigger three blinks of the indicator. Realizing this was an electronic issue, he came up with a way to retrofit this function into his Saab by adding an Arduino Pro Micro to the vehicle’s DICE module.

The DICE (which stands for Dashboard Integrated Central Electronics) module controls many of the accessories in the vehicle, such as the lighting and wipers. In the case of the blinkers, it reads the state of the signal lever switches and turns the blinkers on and off as necessary. After poking around the DICE board, [Saabman] found that the 74HC151 multiplexer chip he was after: the state of the blinker switches could be read from pins 1 and 2, and he’d even be able to pull 5 V for the Arduino off of pin 16.

After prototyping the circuit on a breadboard, [Saabman] attached the Pro Micro to the top of the 74HC151 with some double sided tape and got to work on refining the software side of the project. The Arduino reads the state of the turn signal switches, and if they flick on momentarily it changes the pin from an input to an output and brings it high for three seconds. This makes the DICE module believe the driver is holding the turn lever, and will keep the blinkers going. A very elegant and unobtrusive way of solving the problem.

Hackers aren’t complete strangers to the garage; from printing hard to find parts to grafting in their favorite features from other car manufacturers, this slick Saab modification is in good company.

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The Quick-Build PowerWall

August 11, 2018 by Brian Benchoff 106 Comments

Elon Musk isn’t just the greatest human being — he’s also a great inventor. He’s invented the reusable rocket, the electric car, and so much more. While those are fantastic achievements, Elon’s greatest invention is probably the PowerWall. The idea of a PowerWall is simple and has been around for years: just get a bunch of batteries and build a giant UPS for your house. Elon brought it to the forefront, though, and DIYers around the world are building their own. Thanks, Elon.

Of course, while the idea of building your own PowerWall is simple, the devil is in the details. How are you going to buy all those batteries? How are you going to connect them together? How do you connect it to your fuse box? It’s a systems integration nightmare, made even more difficult by the fact that lithium cells can catch fire if you do something wrong. [jehugarcia] is building his own PowerWall, and he might have hit upon an interesting solution. He’s built a modular system to store and charge hundreds of 18650 cells. It looks great, and this might be the answer to anyone wanting to build their own PowerWall.

Aside from acquiring hundreds of 18650 cells, the biggest problem in building a PowerWall is simply connecting all the cells together. This can be done with 3D printed battery holders, solder, and bus bars, with a few people experimenting with spot welding wires directly onto the cells. This project might be a better solution: it uses standard plastic battery holders easily acquired from your favorite Chinese retailer and a PCB to turn cells into a battery.

The design of this battery module consists of a PCB with sufficiently wide traces, an XT60 power connector, and a few headers for the balance connector of a charger. This is a seven cell setup, and in contrast to the hundreds of hours that go into making a PowerWall the old fashioned way, these modules can be assembled pretty quickly.

Testing of these modules revealed no explosions, and everything worked as intended. There was a problem, though: when drawing a high load, the terminals of these cheap battery connectors got up to 150°. That makes these modules unsuitable for high load applications like an e-bike, but it should be okay if you’re putting hundreds of these modules together to power your house. It might be a good idea to invest in some cooling, though.
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Line Following Robot Without The Lines

August 10, 2018 by Bryan Cockfield 19 Comments

Line-following robots are a great intro to robotics in general, since the materials and skills needed to build a good one aren’t too advanced. It turns out that line-following robots are more than just a learning tool, too. They’re pretty useful in industry, but most of them don’t follow visible marked lines. Some, like this inductive guided robot from [Randall] make use of wires to determine their paths.

Some of the benefits of inductive guidance over physical lines are that the wires can be hidden in floors, so if something like an automated forklift is using them at a warehouse there will be less trip hazard and less maintenance of the guides. They also support multiple paths, so no complicated track switching has to take place. [Randall]’s robot is a small demonstration of a larger system he built as a technician for an autonomous guided vehicle system. His video goes into the details of how they work, more of their advantages and disadvantages, and a few other things.

While inductive guided robots have been used for decades now, they’re starting to be replaced by robots with local positioning systems and computer vision. We’ve recently seen robots that are built to utilize these forms of navigation as well.

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Scanning Tunneling Microscope Packs The Bits

August 10, 2018 by Al Williams 2 Comments

We don’t usually think of a microscope as an active instrument, but researchers in Canada have used a scanning tunneling microscope to remove or replace single hydrogen atoms from the surface of a hydrogen-passivated silicon wafer. If the scientific paper is too much to wade through, there’s an IEEE Spectrum article and a video that might run on the 6 o’clock news below.

As usual with these research projects, there is good news and there is bad news. The good news is that — in theory — a memory device made using hydrogen lithography could store 138 terabytes per square inch. That’s enough, apparently, to store the entire iTunes catalog on a quarter. The bad news? Well, right now this takes exotic lab equipment at very low temperatures and pressures.

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IBM PCjr Revived By An ATX Power Supply And Many False Starts

August 10, 2018 by Dan Maloney 26 Comments

The IBM PCjr was a computer only the marketing geniuses of a multi-billion dollar corporation could love. On the face of it, it seemed like a great idea – a machine for the home market, meant to complement the “big boy” IBM PC in the office and compete against the likes of Apple and Commodore. What it ended up as was a universally hated, only partially PC-compatible machine which sold a mere half-million units before being mercifully killed off.

That doesn’t mean retrocomputing fans don’t still snap up the remaining machines, of course. [AkBKukU] scored a PCjr from a thrift store, but without the original external brick power supply. An eBay replacement for the 18-VAC supply would have cost more than the computer, so [AkBKukU] adapted a standard ATX power supply to run the PCjr. It looked as if it would be an easy job, since the external brick plugs into a power supply card inside the case which slots into the motherboard with a card-edge connector. Just etch up a PCB, solder on an ATX Molex connector, and plug it in, right? Well, not quite. The comedy of errors that ensued, from the backward PCB to the mysteriously conductive flux, nearly landed this one in the “Fail of the Week” bin. But [AkBKukU] soldiered on, and his hand-scratched adapter eventually prevailed; the video below tells the whole sordid tale, which thankfully ended with the sound of the machine booting from the 5-1/4″-floppy drive.

In the end, we’ve got to applaud [AkBKukU] for taking on the care and feeding of a machine so unloved as to be mentioned only a handful of times even on these pages. One of those articles marks the 25th anniversary of the PCjr, and lays out some of the reasons for its rapid disappearance from the market.

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Ease Rover Development With These Self-Contained Track Units

August 10, 2018 by Donald Papp 2 Comments

Tracked drive systems are great, but implementation isn’t always easy. That’s what [nahueltaibo] found every time he tried to use open sourced track designs for his own rovers. The problem is that a tracked drive system is normally closely integrated with a vehicle’s chassis, mixing and matching between designs is impractical because the tracks and treads aren’t easily separated from the rest of the vehicle.

To solve this, [nahueltaibo] designed a modular, 3D printable rover track system. It contains both a motor driver and a common DC gearmotor in order to make a standalone unit that can be more easily integrated into other designs. These self-contained rover tracks don’t even have a particular “inside” or “outside”; they can be mounted on a vehicle’s left or right without any need to mirror the design. The original CAD design is shared from Fusion 360, but can also be downloaded from Thingiverse. A bit more detail is available from [nahueltaibo]’s blog, where he urges anyone who tries the design or finds it useful to share a photo or two.

3D printed tank tracks — including this one — often use a piece of filament as a hinge between track segments and sometimes slightly melted on the ends to act as a kind of rivet, which is itself a pretty good hack.

This Is The Year Of PCB Inductors

August 10, 2018 by Brian Benchoff 35 Comments

It’s a story we’ve told dozens of times already. The cost to manufacture a handful of circuit boards has fallen drastically over the last decade and a half, which has allowed some interesting experiments on what PCBs can do. We’ve seen this with artistic PCBs, we’ve seen it with enclosures built out of PCBs, and this year we’re seeing a few experiments that are putting coils and inductors on PCBs.

At the forefront of these experiments in PCB coil design is [bobricious], and already he’s made brushless and linear motors using only tiny copper traces on top of fiberglass. Now he’s experimenting with inductors. His latest entry to the Hackaday Prize is a Joule Thief, a simple circuit, but one that requires an inductor to work. If you want an example of what can be done with spirals of copper on a PCB, look no further than this project.

The idea was simply to make a Joule Thief circuit. The circuit is not complicated — you only need a transistor, resistor, and an inductor or transformer to boost the voltage from a dead battery enough to light up an LED.

The trick here is that instead of some wire wrapped around a ferrite or an off-the-shelf inductor, [bobricious] is using 29 turns of copper with six mil traces and spacing on a PCB. Any board house can do this, which means yes, you can technically reduce the BOM cost of a Joule Thief circuit at the expense of board space. This is the year of PCB inductors, what else should be be doing with creative PCB trace designs?