An In-Depth Look At The Haptic Smart Knob

At Hackaday, we love those times when we get a chance to follow up on a project that we’ve already featured. Generally, it’s because the project has advanced in some significant way, which is always great to see. Sometimes, though, new details on the original project are available, and that’s where we find ourselves with [Scott Bez] and his haptic smart knob project.

Alert readers may recall [Scott]’s announcement of this project back in March. It made quite a splash, with favorable comments and a general “Why didn’t I think of that?” vibe. And with good reason; the build quality is excellent, and the idea is simple yet powerful. By attaching a knob to the shaft of a brushless DC motor and mounting a small circular LCD screen in the middle, [Scott] came up with an input device that could be reprogrammed on the fly. The BLDC can provide virtual detents at any interval while generating haptic feedback for button pushes, and the LCD screen can provide user feedback.

But how is such a thing built? That’s the subject of the current video, which has a ton of neat design details and build insights. The big challenge for [Scott] was supporting the LCD screen in the middle of the knob while still allowing the knob — and the motor — to rotate. Part of the solution was, sadly, a hollow-shaft motor that was out of stock soon after he released this project; hopefully a suitable replacement will be available soon. Another neat feature is the way [Scott] built tiny strain gauges into the PCB itself, which pick up the knob presses that act as an input button. We also found the way button press haptics are provided by a quick jerk of the motor shaft very clever.

This is one of those projects that seems like a solution waiting for a problem, and something that you’d build just for the coolness factor. Hats off to [Scott] for following up a sweet build with equally juicy details.

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Visualise ESC Problems With LEDs

For many in the RC community, blowing up an Electronic Speed Controller (ESC) means one thing: throwing it away and buying another one. However, if you’re regularly pushing the limits or simply hate waste, fixing failed units is an option. To assist in this task, [LouD] built an ingeniously simple ESC tester.

The board is designed to be wired in parallel with a brushless DC motor when hooked up to an ESC. The board packs two LEDs per phase, wired in opposite directions. Thus, current flow in both directions can be visualised on a phase-by-phase basis. If everything is operational, the red and green LEDs on each phase should glow evenly as the throttle is ramped up. However, if there are problems, it will be readily apparent as the blinking becomes erratic or one or more LEDs fails to light at all.

It’s a nifty little device that would prove useful when testing¬† a pile of possibly-defective units. It’s also a quick way to verify a fix. The project is up on OSHPark should you wish to order your own.

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The Spin Cycle: Washing Machine Motor Converts 10-Speed To E-Bike

The “Spin Cycle” is an amazing electric bicycle built using a motor salvaged from a washing machine; when the puns are this perfect you have to roll with them. [jimminecraftguy’s] creation is one of the most hacked-together yet functional electric vehicle we’ve seen in a long time.

The drive train of this bicycle starts with a brushless DC motor from a washing machine. It has been slightly modified to run on 48 volts, and is installed inside the triangle of the bike’s frame. It has a chain driving the bike’s crank, retaining the original chain and gearing setup (unlike many electric bike hacks that utilize hub motors). The crank has also been specially modified to include a freewheel, a necessary feature so that the motor can operate without spinning the pedals. Everything except the motor has been custom fabricated including the mounts and the electronics.

[jimminecraftguy] reports speeds of 110 kph which is a little crazy for a 20-year-old aluminum frame bike, and we’d guess it’s not street legal in many jurisdictions, but we can’t really find much fault with this build in general based on the amount of innovation required to get this working at all. A few more improvements for the build are in the works, including improved batteries and a cover for the sides to keep the local law enforcement from getting too suspicious. We can’t wait to see the final version. Continue reading “The Spin Cycle: Washing Machine Motor Converts 10-Speed To E-Bike”