Implementing SENT Sensors On The Raspberry Pi

December 22, 2020 by Lewin Day 12 Comments

The SENT protocol, standing for Single Edge Nibble Transmission, is used for sensors that need to send high-resolution data while keeping system costs low. It’s most typically used in the automotive world, where it can be found in such parts as throttle-by-wire pedals and temperature sensors. [Mark Smith] set out to see if he could get the Pi Zero to read such sensors without the use of an intermediate microcontroller.

[Mark]’s initial attempts relied on Python and the RPI.GPIO library. Unfortunately, the overheads introduced made decoding SENT traffic impossible. Undeterred, [Mark] pressed on, leveraging the pigpio library and its callback function which allowed sampling at up to one microsecond. This was fast enough to read the messages from a LX3302A inductive position sensor that uses the protocol.

It’s a project that could prove useful for those trying to work with certain sensors who want to avoid adding complexity to a Raspberry Pi project. Files are available on Github for the curious. We’ve seen other direct sensor builds with the Pi, before too – like this power monitoring system. Video after the break.

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World Solar Challenge: How Far In A Solar Car?

December 21, 2020 by Lewin Day 90 Comments

Solar power is a great source of renewable energy, but has always had its limitations. At best, there’s only 1,000 Watts/m² available at the Earth’s surface on a sunny day, and the limited efficiency of solar panels cuts this down further. It’s such a low amount that solar panels on passenger cars have been limited to menial tasks such as battery tending and running low-power ventilation fans.

However, where some might see an impossibility, others see opportunity. The World Solar Challenge is a competition that has aimed to show the true potential of solar powered transport. Now 30 years since its inception, what used to be impossible is in fact achieved by multiple teams in under one tenth of the original time. To keep competitors on their toes, the rules have been evolving over time, always pushing the boundaries of what’s possible simply with sunlight. This isn’t mainstream transportation; this is an engineering challenge. How far can you go in a solar car?

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Hypercar Valve Technology On A Harbour Freight Engine

December 17, 2020 by Danie Conradie 45 Comments

The inlet and exhaust valve timing of a piston engine plays a large role in engine performance. Many modern automotive engines have some sort of variable valve timing, but the valves are still mechanically coupled together and to the crankshaft. This means that there is always a degree of performance compromise for various operating conditions. [Wesley Kagan] took inspiration from Koenigsegg’s camless Freevalve technology, and converted a Harbour Freight engine to camless technology for individual valve control.

By eliminating the traditional camshaft and giving each valve its actuator, it is possible to tune valve timing for any specific operating condition or even for each cylinder. A cheap single-cylinder engine is a perfect testbed for the garage hacker. [Wesley] removed the rocker arms and pushrods, and replaced the stock rocker cover with a 3D printed rocker cover which contains two small pneumatic pistons that push against the spring-loaded valve stems. These pistons are controlled by high-speed pneumatic solenoid valves. A reference timing signal is still required from the crankshaft, so [Wesley] built a timing system with a 3D printed timing wheel containing a bunch of embedded magnets and being sensed by a stationary Hall effect sensor. An Arduino is used to read the timing wheel position and output the control signals to the solenoid valves. With a rough timing program he was able to get the engine running, although it wouldn’t accelerate.

In the second video after the break, he makes a digital copy of the engine’s existing camshaft. Using two potentiometers in a 3D printed bracket, he measured push rod motion for a complete engine cycle. He still plans to add position sensing for each of the valves, and after a bit more work on the single-cylinder motor he plans to convert a full-size car, which we are looking forward to.

People have been tinkering with cars in their garage for as long as cars have existed. [Lewin Day] has been doing a series on how to get into tinkering with cars yourself. With all the electronics in modern automobiles, messing around with their software has become a growing part of this age-old pastime. Continue reading “Hypercar Valve Technology On A Harbour Freight Engine” →

How To Get Into Cars: Drag Racing Mods

December 17, 2020 by Lewin Day 20 Comments

While some love to carve up mountain roads, and others relish the challenge of perfectly apexing every corner at the track, many crave a different challenge. Drag racing is a sport all about timing, finesse, and brute power. Like any other discipline in motorsport, to compete you’ll need a vehicle finely honed for the task at hand. Here’s how you go about getting started on your first quarter-mile monster.

It’s All About Power, Right?

It’s true that if you want to go faster, having more power on tap is a great way to do it. If that’s what you’re looking for, we’ve covered that topic in detail – for both the naturally aspirated and forced induction fans. However, anyone that’s been to the drag strip before will tell you that’s only part of the story. All of the power in the world isn’t worth jack if you can’t get it down to the ground. Even if you can, you’ve still got to keep your steering wheels planted if you intend to keep your nose out of the wall. So, if you want more power, consider the articles linked above. For everything else that’s important in drag racing, read on below.

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Alfa Romeo Gauge Cluster Gets A Fresh Set Of LEDs

November 26, 2020 by Tom Nardi 16 Comments

On older vehicles, if you noticed that the lights had gone out behind one of your gauges, you knew it was time to snake your hand back there and replace the little incandescent bulb that had given up the ghost. But what are you supposed to do if you’re seeing the same problem on a modern vehicle that’s already made the leap to LED dash lighting? That’s what [Tysonpower] recently had to find out when the fuel indicator on his Alfa Romeo Giuletta QV went dark.

In the video after the break, [Tysonpower] details how to remove the instrument cluster from the Giuletta’s dash, which we imagine would be a useful little tutorial for anyone who owns the same vehicle. Once he has it out on the bench, he strips it down to the bare PCB and starts (literally) poking around.

He eventually noticed that if he pushed on the board near the fuel indicator he could get the appropriate 3528 SMD LED to light up, but touching up the solder joints didn’t seem to fix the issue. Assuming the LED must be defective internally, he simply replaced it and all was good again.

Well, not exactly. The light produced by the new part didn’t match the color or brightness of the other dozen or so white LEDs that were installed on the board, so [Tysonpower] decided to just dive in and replace them all. While it obviously took a lot more time and effort, he says the end result is that the instrument cluster looks noticeably brighter and crisper when driving at night. Not bad for an afternoon’s work and a couple bucks worth of LEDs.

Most of the time, when we see somebody messing around behind the dash it’s because they intend on replacing the original instruments with something more capable. But projects like this, which add just a touch of refinement to the existing hardware, prove that stock components aren’t always a disappointment.

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Alfred Jones Talks About The Challenges Of Designing Fully Self-Driving Vehicles

November 24, 2020 by Mike Szczys 44 Comments

The leap to self-driving cars could be as game-changing as the one from horse power to engine power. If cars prove able to drive themselves better than humans do, the safety gains could be enormous: auto accidents were the #8 cause of death worldwide in 2016. And who doesn’t want to turn travel time into something either truly restful or alternatively productive?

But getting there is a big challenge, as Alfred Jones knows all too well. The Head of Mechanical Engineering at Lyft’s level-5 self-driving division, his team is building the roof racks and other gear that gives the vehicles their sensors and computational hardware. In his keynote talk at Hackaday Remoticon, Alfred Jones walks us through what each level of self-driving means, how the problem is being approached, and where the sticking points are found between what’s being tested now and a truly steering-wheel-free future.

Check out the video below, and take a deeper dive into the details of his talk.

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How To Get Into Cars: Offroading Mods

November 18, 2020 by Lewin Day 44 Comments

While plenty of automotive enthusiasts are all about carving corners at the local track days, it’s a special breed that leaves tarmac behind for the dusty trail ahead. If your chosen ride is of the four-wheelin’ variety, here’s how you can modify it to dominate the dirt and mud.

Handling The Terrain

Building a good offroad rig requires a very different focus than building a car for street performance. A screaming high-performance engine is of no use when your tires are spinning in the air because you’re stuck in deep sand or on top of a pointy rock. Instead, four wheelers are concerned with a whole different set of parameters. Ground clearance is key to getting over obstacles without getting stuck, and good articulation is key to keeping your wheels on the ground and pushing you forward in deep ruts and on crazy angles. You’ll also want plenty of low-down torque, and tyres that can grip up in all conditions without snagging a puncture. It’s a whole different ballgame, so read on!

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