Month: January 2022

Ride-on Tracked Vehicle Is A Stout Metal Build

January 13, 2022 by 17 Comments

When we think of tracked vehicles, we normally think of tanks, or perhaps heavy construction machinery. Meanwhile the average member of the public is left out of the fun. [Bob] of [Making Stuff] won’t be one of them, however, having put together a ride-on tracked vehicle for his own enjoyment.

The machine is welded together from plenty of steel, making it more than tough enough to soak up the punishment of off-road duty. The design features four suspended buggy wheels on either side running inside rubber tracks, with a cogged drive wheel at the front. Propulsion is thanks to a 440 cc DuroMax engine good for a full 18 horsepower and 26 ft-lbs of torque, driving the tracks through a differential mounted up front.

The design has one major issue at the moment. The heavy engine is mounted ahead of the front wheel inside the tracks, which means the vehicle wants to nosedive at the slightest provocation. Such an event would be highly uncomfortable for the rider, so mods are needed, either by scooching the engine back a little or pushing the wheels forward.

We look forward to seeing [Bob] fix the issues and get the machine driving soon. We’ve seen other tracked builds before, too – often on the smaller scale. Video after the break.

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Exploring Tesla Model S High Voltage Cabling

January 13, 2022 by 36 Comments

When he’s not busy with his day job as professor of computer and automotive engineering at Weber State University, [John Kelly] is a prolific producer of educational videos. We found his video tracing out the 22+ meters of high voltage cabling in a Tesla Model S (below the break) quite interesting. [John] does warn that his videos are highly detailed and may not be for everyone:

This is not the Disney Channel. If you are looking to be entertained, this is not the channel for you.

We ignored the warning and jumped right in. The “high” voltages in the case of an electric vehicle (EV) like the Model S is approximately 400 volts. Briefly, external input via the charge connector can be single or three phase, 120 or 250 VAC, depending on your region and charging station. This get boosted to a nominal 400 VDC bus that is distributed around the various vehicle systems, including the motors and the battery pack.

Rear Modules

    • Charge receptacle
    • On-board charger module
    • Rapid splitter
    • Rear motor inverter

Front Modules

    • High voltage junction block
    • Cabin air heater
    • DC to DC converter
    • Battery coolant heater
    • Air conditioning compressor
    • Front motor inverter

He goes through each module, showing in detail the power routing and functionality, eventually assembling the whole system spanning two work benches. We liked his dive into the computer-controlled fuse that recently replaced the standard style one, and were impressed with his thorough use of labels.

If you’ve ever been curious about the high voltage distribution of a EV, grab some popcorn and check out this video. Glancing through his dozens of playlists, [John]’s channel would be a good place to visit if you’re interested any topic related to hybrids and electric vehicles, drive trains, and/or transmissions. We’ve written about some Tesla teardowns before, the Model 3 and the Model S battery packs. Have you worked on / hacked the high voltage system in your EV? Let us know in the comments below.

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Remoticon 2021 // Hash Salehi Outsmarts His Smart Meter

January 13, 2022 by 27 Comments

Smart meters form mesh networks among themselves and transmit your usage data all around. Some of them even allow the power company to turn off your power remotely, through the mesh. You might want to know if any of this information is sensitive, or if the power shutdown system has got glaring security flaws and random people could just turn your house off. Hash Salehi has set out to get inside these meters, and luckily for the rest of us, he was kind enough to share his findings during Remoticon 2021. It’s a journey filled with wonderful tidbits about GNU Radio, embedded devices, and running your own power company inside a Faraday cage.

The smart meter in question is deployed by a power company known as Oncor in the Dallas, Texas, area. These particular meters form an extensive mesh network using a ZigBee module onboard that allows them to to pass messages amongst themselves that eventually make their way to a collector or aggregator to be uploaded to a more central location. Hash obtained his parts via everyone’s favorite online auction house and was surprised to see how many parts were available. Then, with parts in hand, he began all the usual reverse engineering tricks: SDR, Faraday cages, flash chip readers, and recreating the schematic. Continue reading “Remoticon 2021 // Hash Salehi Outsmarts His Smart Meter” →

Impedance Matching Revisited

January 13, 2022 by 15 Comments

If you are an old hand at RF design, you probably have a good handle on matching impedance. However, if you are just getting started with RF, [FesZ Electronic]’s latest video series on lossless impedance matching is well worth watching.

Matching is important for several reasons. Maximum power transfer occurs when the source and load impedance match. Also, at RF, mismatched impedance can cause reflections which, again, robs you of useful power. The video covers some math and then moves on to LTSpice to simulate a test circuit. But the part you are really waiting for — the practical circuits — is about 15 minutes in. Since the values you need are often oddball, [FesZ] makes his own adjustable inductors and uses a trimmer capacitor to adjust the actual capacitance value.

This is a big topic, but the first video is a great introduction blending theory, simulation, and hands-on. A great way to get started with a very fundamental RF design skill.

We’ve worked on explaining all this before if you want a second take on it. If you want to understand why mismatched impedance leads to less power delivery, we’ve done that, too.

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Four Wheel Steering, Always The Option, Never The Defining Feature

January 13, 2022 by 67 Comments

A couple of weeks ago when it emerged that a new Tesla might have a four-wheel steering capability, our colleague Dan Maloney mused aloud as to how useful a four-wheel steering system might be, and indeed whether or not one might be necessary at all. This is hardly the first time four-wheel steering has appeared as the Next Big Thing on the roads. It’s time to take a look at the subject and ask whether it’s an idea with a future, or set to go the way of runflat tyres as one of those evergreen innovations that never quite catches on.

What’s your dream vehicle? If you’re like me, you have more than one. There in my lottery-winner’s garage, alongside the trail bikes and the mobile hackerspace, the dictator-size Mercedes and the Golf Mk1, will be a vehicle that by coincidence has four-wheel steering. The JCB Fastrac is a tractor that can travel across almost any terrain at full speed, and though I have no practical use for one and will never own one, I have lusted after one of these machines for over three decades. Their four-wheel steering system is definitely unusual, but that makes it the perfect vehicle with which to demonstrate four-wheel steering. Continue reading “Four Wheel Steering, Always The Option, Never The Defining Feature” →

Canon Temporarily Abandons Smart Ink Cartridges

January 13, 2022 by 49 Comments

An unexpected side effect of the global semiconductor shortage came to light this week — Japanese printer manufacturer Canon announced they are temporarily going to provide consumable ink and toner cartridges without microchips. Furthermore, they provided instructions for consumers on how to bypass the printer’s logic, allowing it to function even when it incorrectly thinks the ink or toner is low. Included in the announcement (German), the company stated what most people already knew:

There is no negative impact on print quality when using consumables without electronic components.

It’s well known that many printer companies make their profit on the consumable cartridges rather than the printers themselves. And most printers require consumers to only use factory original cartridges, a policy enforced by embedded security ICs. Use a third-party ink cartridge and your printer will likely refuse to print. There are legitimate concerns about poor quality inks damaging the print heads. But with reports like this 2003 one from the BBC noting that 17% to 38% additional good quality pages can be printed after the consumable is declared “empty”, and that the price per milliliter of inks is seven times the cost of vintage champagne, one can reasonably conclude that these DRM-protected consumables are more about on ensuring profits than protecting the hardware.

For now, this announcement applies to German customers, and covers the Canon imageRunner family of multi-function printers (the complete list is in the company announcement above).

Work The World On A 555

January 13, 2022 by 14 Comments

Over the years the humble 555 timer has been used in so many unexpected places, but there’s a project from [Frank Latos] which we think may be a first. On a piece of stripboard sit a pair of 555s, and instead of the usual passives there are a set of LC circuits. This is no timer, instead it’s a CW (Morse) transmitter for the 80 metre amateur radio band.

One 555 is configured as a feedback oscillator through a toroidal transformer with a tuned circuit to set the frequency of oscillation. The other takes an inverted input from the oscillator to produce complimentary push-pull outputs from both 555s, which are fed to another transformer that in turn feeds a low-pass filter and thus the antenna.

Free-running squarewave oscillators of this type are not unusual for the lower HF bands, but we think this is the first 555 design we’ve seen. As shown it doesn’t produce much in the way of RF power, but remembering half-decent motor drivers using a 556 dual timer we think that selection of one of the more powerful 555 variants might deliver some more punch. We commend his creativity though, and hope he can get that all-important entry in the log to prove it works.

If you’re curious about low-power radio operation, it’s something we’ve explored before.