Independent Wheel Drive R/C Car

4wdRcCar

The picture above looks like a standard four-wheel drive (4WD) touring car. As one looks closer, a few strange things start to pop out. Where’s the motor? 4 electronic speed controls? What’s going on here? [HammerFET] has created this independent drive R/C car (YouTube link) as a research platform for his control system. The car started off life as a standard Schumacher Mi5 1/10th scale Touring Car. [HammerFET] removed the entire drive system. The motor, differentials, belt drive, and ESC all made for quite a pile of discarded hardware.

He replaced the drive system with 4 Turnigy brushless outrunner motors, installed at the chassis center line. To fit everything together, he had to 3D print new drive cups from stainless steel. The Mi5’s CVD drive shafts had to be cut down, and new carbon fiber suspension towers had to be designed and cut.

The real magic lies in [HammerFET's] custom control board. He’s using an STM32F4 ARM processor and an InvenSense  MPU-6050 IMU which drone pilots have come to know and love. Hall effect sensors mounted above each motor keep track of the wheel speed, much like an ABS ring on a full-scale car.

[HammerFET's] software is created with MATLAB and SimuLink. He uses SimuLink’s embedded coder plugin to export his model to C, which runs directly on his board. Expensive software packages for sure, but they do make testing control algorithms much simpler. [HammerFET's] code is available on Github.

Since everything is controlled by software, changing the car’s drive system is as simple as tweaking a few values in the code. Front and rear power offset is easily changed. Going from a locked spool to an open differential is as simple as changing a value from 0 to 1. Pushing the differential value past 1 literally overdrives the differential. In a turn, the outer wheel will be driven faster than it would be on a mechanical differential, while the inner wheel is slowed down. Fans of drifting will love this setting!

[HammerFET] is still working on his software, he hopes to implement electronic torque vectoring. Interested? Check out the conversation over on his Reddit thread.

 

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Museums Should be More Popular Than Theme Parks

One of the field trips that we set up as part of our Detroit tour was a trip to The Henry Ford Museum. After a rather disappointing first half hour wandering around the static exhibits of nicely polished cars we latched onto the part of the museum that’s starts the serotonin pump for anyone who is engineering-minded. There are amazing displays of early industrialization, including steam engines for factories, early power generators, and examples of early assembly line machinery. We’re going to cover that stuff in depth but editing it all together will take some time.

For now we wanted to give you a quick glimpse at a delightful exhibit of a Model T. You don’t just look at it; every morning the museum staff takes apart the entire vehicle and throughout the day helps museum-goers walk through the process of putting it back together.

Why isn’t this the model to supplant amusement parks? This hands-on work with real equipment — not just a model made to stand up to the masses — is pure gold for occupying curious people of all ages. The interaction with museum staff adds a tangible human element to the institution, and you just might learn something more than history in the process!

[Full Disclosure: The Henry Ford provided Hackaday with free admission -- Thank You!]

A Most Impractical Gear Position Indicator

GPI A few years ago, [Pat] sent in a really nice gear position indicator for his Suzuki V-Strom. With a single seven-segment display , a small microcontorller, and wires tied right into the bike’s ECM, it’s more than enough to do its job, and is much cheaper than aftermarket gear indicators. A simple, elegant solution that does one job well. How could this possibly be any better?

‘Better’ is a relative term, and depending on what you’re optimizing for, a more complex solution can easily be superior. [Pat] figured tripling the value of his motorcycle is a worthwhile goal, so he replaced that seven-segment display with an oscilloscope. It’s the world’s only oscilloscope based motorcycle gear position indicator, and now [Pat] needs a really, really long extension cord.

Like the earlier, more practical version, This build reads the voltage off the bike’s ECM to determine what gear the bike is in. The current gear is then displayed on a Tek MDO3000 with two PWM pins on a microcontroller. Practical? No, but it does look cool. Video below.

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Tempo Keeping Drummer Leaves Viking Ship, Now Inspires Pedallers

Bike Controlled Drum Machine

[Serdef] wrote in to tell us about a project he has recently created. It’s a drum beat generator that changes tempo depending on how fast you pedal your bike. This flies directly in the face of using music to keep your pedal timing consistent and up to speed.

The project started out with a tap-tempo drum rhythm pedal that [Serdef] had previously built. This device will generate a drum beat at a tempo corosponding with the time between 2 input signals. This type of device allows someone, say a guitarist, to quickly and easily specify the speed of the drumbeat that they are playing along with.

With the meat and potatoes of the project already figured out, the next part was to make the speed of the bike trigger the tempo of the drum beat. For the signal input, a magnet mounted on the wheel triggers a reed switch mounted on the bike fork once per wheel revolution. This is the same method of information gathering that a bicycle speedometer/odometer uses.

The business part of this project includes an Arduino that measures the speed of the wheel via the magnetic switch, adjusts the speed of the drum beat, and then sends the drum beat to a synthesizer via MIDI protocol. The synthesizer converts the MIDI signal into drum sounds amplified through a powered speaker that the rider can hear. The entire system is powered by a 9v battery and housed in a project box strapped to the bike’s handlebars.

All of the design files and Arduino code are available via [Serdef's] excellent write up on hackaday.io in case you’re interested in making one for yourself.

Open Source Electric Car, CarBEN, Produces No Carbon

CarBEN Open Source Electric Car

Raise your hand if you have designed and built a full size car…. Nobody? Doing so would be a huge task considering car manufactures have thousands of people involved with designing and building a car model. Eager beaver [Neil] has stepped up and taken on that challenge. He’s started an open source project he’s calling the CarBEN.

CarBEN Open Source Electric Car

The plan is for the car to hold 5 people comfortably while being just a tad larger than a Scion xA. The body is made of foam and will be covered with fiberglass. The car is designed in a shape that tapers in towards the rear of the car and has features like a smooth underside and covered wheels to create a low coefficient of drag. The goal is for this beauty to get 300-400 miles per charge with an Miles Per Gallon Equivalent of over 224.

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A Head Unit Docking Station

dock

[Ivan] had a simple idea: being able to control his Android device from the small keypad on his car’s steering column. This would allow him to cycle through apps, navigation, and audio tracks while never taking his hands off the wheel. Feature creep then set in and [Ivan] asked himself how he could charge his phone through the same interface. What he ended up with is a head unit that’s also a dock.

While [Ivan]‘s steering wheel doesn’t have the nice integrated remote control buttons found in newer cars, he does have a Blaupunkt remote, a small, clip-on controller that has a an IR transmitter on it. The IR receiver was connected to a PIC microcontroller, sending commands to the phone for up, down, left, right, menu, and home. Audio output from the phone is handled by a small USB sound card connected to a USB hub, sending the audio signals directly into the head unit’s amplifier.

Having the phone charge while it’s still in USB host mode is the crucial part of this build; not being able to charge on a long car ride would quickly drain the battery and make a car dock kind of pointless. To accomplish this, [Ivan] simulated a Galaxy S4 dock with a few resistors in the USB port, allowing the phone to control the USB sound card, listen to the emulated keyboard and mouse, and charge at the same time.

It’s not a pretty build, but it is extraordinarily useful. In the videos you can see that [Ivan] pretty much pulled this build together from stuff he had sitting around – a great reuse of junk, and a great addition to his car at the same time.

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Three-Phase Submersible Thruster is Open Source and Awesome

submerged_mellon_assembly_v8

Have you ever considered building some kind of underwater vehicle? It’s rather ambitious but [Dane] of Transistor-Man has designed and built a working submersible 3-phase electric thruster — and he’s released the plans online for all to share!

He decided to make this for his 3D printed canoe (another awesome project) which is possible due to his massive SCARA robot 3D printer. The thruster makes use of readily available off the shelf components, but with 3D printed cones for decreased water resistance and other manufactured parts. The housing is water-jet cut, and the poly-carbonate tube had grooves for seals made using a lathe.  The amount of detail in his build logs is incredible — he’s fully modeled all parts in what looks like SolidWorks and uploaded detailed images and designs of all the parts.

The trickiest part of the build was making it water-tight. His first test was to submerge it in a water bath for 8 minutes, and once that was proven, he filled the inside with 5W-20 oil to make sure it wouldn’t leak the other way as well. One of his project goals is for this thruster to work 1 meter underwater without losing more than 10ml of the coolant (oil) per hour.

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