Building An Aluminum RC Truck From Scratch

September 5, 2021 by Adam Fabio 14 Comments

These days you can get just about any kind of radio controlled vehicle as a ready-to-run model. Cars, trucks, excavators, you name it. Open the box, charge the batteries, and you’re ready to roll. Even with all these modern conveniences, there is still a special breed of modelers who create their own models using only a few off-the-shelf parts.

[Rini Anita] is exactly that rare breed, creating this aluminum RC truck from scratch. The truck itself is a cab-over — short for Cab Over Engine (COE), a style seen making local deliveries worldwide. He starts with the ladder frame chassis, which is constructed using an extruded aluminum channel. This is the same material you’d normally use for the door tracks in retail store display cases. The electronics and standard RC fare: a receiver, electronic speed control, and a servo for steering. Batteries are recycled lithium cells. The main gearbox and drive axle look to be sourced from another RC vehicle, while leaf springs and suspension components are all custom built.

The truck’s body is a great example hand forming metal. First, a wooden form was created. Sections for the windows and door panels were carved out. Sheet aluminum was then bent over the wood form. Carefully placed hammer blows bend the metal into the carved sections – leaving the imprints of doors, windows, and other panel lines.

Throughout this build, we’re amazed by [Rini]’s skills, and the fact that the entire job was done with basic tools. A grinder, an old drill press, and a rivet gun are the go-to tools; no welder or 3D printer to be found. This puts a project like this well within the means of just about any hacker — though it may take some time to hone your skills! For his next truck, maybe [Rini] can add a self driving option!

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Fan Lets RC Car Drive On The Ceiling

September 4, 2021 by Lewin Day 7 Comments

Downforce is a major part of modern motorsport, keeping cars glued to the track at high speeds. However, for small radio control cars, adding a fan for a little suction can achieve even greater feats, as demonstrated by this build by [DD ElectroTech].

The build began as a simple two-motor, skid-steer RC car build with a fan for suction. Controlled by a smartphone app, a cheap Arduino board with an HC-05 Bluetooth module ran the show. However, when this was all assembled, the car was too heavy to climb walls or stick to the ceiling.

Thus, a weight-saving plan was in order. Wheels were swapped out for lighter 3D printed parts. The electronics saw significant re-engineering, too, with the multiple separate modules all condensed down into one single custom PCB. After a few other tweaks, the new lighter car was able to easily drive on the ceiling and even climb walls, albeit with some difficulty.

It’s a fun little build and a good demonstration of how easy it is to whip up cool projects with modern electronics and 3D printed parts. We’ve seen other printed fan car builds before, too, but did you know the concept was first trialed in real-world motorsport competition? Video after the break.

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Never Lose A Piece With 3D Printed Sliding Puzzles

August 28, 2021 by Jim Heaney 6 Comments

Have you ever been about to finish a puzzle, when suddenly you realize there are more holes left than you have pieces? With [Nikolaos’s] 3D printed sliding puzzles, this will be a problem of the past!

An image showing the sliding dovetails of the puzzle — The dovetails, integrated into each piece, keep the puzzle together but still allows pieces to move.

The secret of the puzzle is in the tongue and groove system that captures the pieces while allowing them to slide past each other and along the puzzle’s bezel. The tongues are along the top and right sides of the pieces shown here, with the grooves along the left and bottom. There is only one empty spot on the board, so the player must be methodical in how they move pieces to their final destinations. See this in action in the video after the break.

[Nikolaos] designed the puzzle in Fusion 360, and used this as an opportunity to practice with parameters. He designed the model in such a way that any size puzzle could be generated by changing just 2 variables. Once the puzzle is the proper size, the image is added by importing and extruding an SVG.

Another cool aspect of these puzzles is that they are print-in-place, meaning that when the part is removed from the 3D printer, it is ready to use and fully assembled. No need to remove support material or bolt and glue together multiple components. Print-in-place is useful for more than just puzzles, you could also use this technique to 3D print wire connectors!

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80's vintage Tomy Omnibot and Futaba RC Transmitter

80’s Omnibot Goes RC And Gets A Modern Refresh

August 22, 2021 by Ryan Flowers 5 Comments

Thrift stores, antique shops, knick-knack stores- Whatever you might call them in your locale, they’re usually full of “another man’s treasure”. More often than not, we leave empty-handed, hoping another shop has something we just can’t live without. But on rare occasions, when the bits all flip in our favor, we find real gems that although we have no idea what we’re going to do with them, just have to come home with us.

[Charles] ran into this exact situation recently when he walked into yet another shop among many dotting the highways and byways of Georgia and spotted it: A Tomy Omnibot beckoning to him from the 1980s. [Charles] didn’t know what he’d do with the Omnibot, but he had to have it. Not being one to have things just sit around, he set out to make it useful by combining it with an era-appropriate Futaba 4 channel AM radio, and updating all of the electronics with modern hardware. The Mission? Drive it around at car shows and meetups where he already takes his 1980’s era vans.

We’re not going to spoil the goodies, but be sure to read [Charles]’ blog post to see how he hacked a modern 2.4 GHz 7 channel radio into the vintage Futaba 4 channel AM radio case. We appreciated his analytical approach to meshing the older gimbals and potentiometers with the new radio guts. Not to mention what it took to get the Omnibot back into service using parts from his battle bots bin. You’ll love the attention to detail on the new battery, too!

We’ve featured [Charles] work in the past, and his Power Wheels racer fed by a recovered Ford Fusion battery is simply unforgettable. You might also appreciate another Omnibot revival we featured recently. And as always, if you have a hack to share, submit it via the Tip Line!

A Cold Gas Thruster On An RC Car

August 15, 2021 by Lewin Day 12 Comments

Tesla have boldly claimed that one day they’ll ship a Roadster complete with a cold-gas thruster for truly ridiculous acceleration. Whether or not that ever comes to pass remains to be seen, but [Engineering After Hours] decided to try out the technology on an RC car instead.

The thruster uses a pair of disposable CO2 canisters to deliver 1770 g of thrust via a converging-diverging nozzle. Actuated by servos and a simple valve, the system dumps the high-pressure CO2 to help accelerate the car up to speed. Paired with sticky tires and a powerful brushless motor, the plan was to try and beat Tesla’s claimed 1.1 second 0-60mph acceleration figure for the thruster-boosted roadster.

Unfortunately, the high center of gravity of the RC car led to stability issues, largely due to the mounting of the thruster itself. Additionally, the high weight of the car – around 4.3kg – meant that at best, the thruster would only add 0.5g to the vehicle’s acceleration.

While the car didn’t net a quick 0-60 time, it’s still neat to see a cold gas thruster on an RC car. It may not have been a Tesla-beater like some earlier projects, but it was cool all the same. Video after the break.

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Nintendo Zapper Reborn As Home Automation Remote

August 7, 2021 by Brian McEvoy 3 Comments

Generally, using a gun to turn your lights off is dangerous and expensive, but for the [DuctTape Mechanic], it’s just how he does things. Video also after the break. To be fair, he uses a salvaged Nintendo Zapper, not a firearm, and replaces the guts with an RF transmitter. We are shocked that he chose a radio model instead of infrared seeing as how he is repurposing a light gun, but our scores in Duck Hunt suggest he made the right choice.

The transmitter comes from a keychain remote, so it all fits neatly inside the Zapper chassis. A couple of wires hijack the stock button and run to the stock trigger, so you keep that authentic feel. The receiver side is a bit trickier. When it senses a button press, it sends a pulse, as you would find in a garage door opener, but to keep a lamp on, there needs to be some latching and so there is an Arduino. The microcontroller keeps a tally and operates a 10 amp relay module, so it is mostly acting as the glue between hardware. All of the mains electrical components sit in a blue plastic box with a receptacle on the front.

We don’t see the Zappers used for their intended purposes much anymore because they rely on old technology, but that doesn’t keep people from repurposing the iconic peripheral.

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Foam F-35 Learns To Hover

July 15, 2021 by Tom Nardi 2 Comments

With cheap RC hardware, powerful motors, and high-capacity battery packs, getting something to fly has never been easier. It also helps that, whether you’re into fixed-wing craft or multirotors, there’s plenty of information and prior art floating around online that you can use to jumpstart your own build. But when it comes to homebrew vertical take-off and landing (VTOL) planes, things are a bit trickier.

Luckily for us, [Nicholas Rehm] has made all the plans and information necessary to duplicate his incredible RC F-35 available for anyone who wants to experiment with these relatively niche fliers. Even if it was a standard park flier, the build would be worth a close look thanks to the vectored thrust motors that give it phenomenal maneuverability and a top speed in the neighboorhood of 120 KPH (80 MPH). But with the flick of a switch, the plane transitions into a tricopter-like flight mode that allows it to land and takeoff vertically.

How does it work? The downward facing motor just behind the “cockpit” lifts up the front of the foam flier and tilts left and right to provide yaw control, while the two motors on the back tilt down to lift up the rear of the aircraft. Aviation buffs in the audience may recognize this as being fairly close to how the actual F-35B hovers, although on the real jet fighter, downward thrust under the wings is generated by redirected turbine exhaust rather than dedicated motors, and yaw control is provided by swiveling the engine’s nozzle rather than the front lift fan.

Getting the plane to takeoff vertically was one thing, but being able to transition from a hover into forward flight was quite another. To make this aerial transformation possible [Nicholas] actually had to write his own flight controller software, which he calls dRehmFlight. The GPLv3 code runs on the Teensy 4.0 and uses the common GY-521 MPU6050 gyroscope/accelerometer, so you don’t need to get any custom boards spun up just to give it a test ~~drive~~ flight. In the video below he walks through configuring the software for VTOL operation by defining how each control surface and motor is to respond to control input given the currently selected flight mode.

It probably won’t surprise you to hear that this isn’t the first time [Nicholas] has experimented with unusual flying machines. Last year we covered his RC Starship, which managed to stick the “belly flop” landing even before SpaceX managed to get the real life version down in one piece.

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