Ultrasonic Array Gets Range Data Fast and Cheap

How’s your parallel parking? It’s a scenario that many drivers dread to the point of avoidance. But this 360° ultrasonic sensor will put even the most skilled driver to shame, at least those who pilot tiny remote-controlled cars.

Watch the video below a few times and you’ll see that within the limits of the test system, [Dimitris Platis]’ “SonicDisc” sensor does a pretty good job of nailing the parallel parking problem, a driving skill so rare that car companies have spent millions developing vehicles that do it for you. The essential task is good spatial relations, and that’s where SonicDisc comes in. A circular array of eight HC-SR04 ultrasonic sensors hitched to an ATmega328P, the SonicDisc takes advantage of interrupts to make reading the eight sensors as fast as possible. The array can take a complete set of readings every 10 milliseconds, which is fast enough to allow for averaging successive readings to filter out some of the noise that gets returned. Talking to the car’s microcontroller over I2C, the sensor provides a wealth of ranging data that lets the car quickly complete a parallel parking maneuver. And as a bonus, SonicDisc is both open source and cheap to build — about $10 a copy.

Rather use light to get your range data? There are some pretty cheap LIDAR units on the market these days.

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ESP8266 Adds Slick Touchscreen Controls to a Stretch Limo

The popularity of the ESP8266 WiFi module has a lot to do with its ability to inexpensively connect to the Internet. However, [hwhardsoft]’s stretch limousine environmental control system explores another use for these modules: a simple way to tie together disparate systems with a common user interface.

On a basic level, the problem is one we’ve all faced: multiple devices with multiple control interfaces create an awkward user experience. Have you ever worked in an office with 6 brands of air conditioner requiring 6 different remotes? Because of its low-cost, support for Wi-Fi, serial, and GPIO, ESP8266 boards are a reasonable candidate to create a unified control system for multiple devices. This is even more true for the ESP32, as it adds Bluetooth support.

[hwhardsoft]’s use case is fairly straightforward. The limousine (a Lincoln stretch) has multiple LED lighting controllers, climate control, and a laser projector. This was not exactly a smooth user experience, so [hwhardsoft] tied all the controls to two slick touchscreen interfaces (presumably one for the driver and one for the passengers).

Each touchscreen sends commands over Wi-Fi using UDP to a control board that switches relays to control the different devices, as we’ve seen previously.

While relays are arguably not the ideal solution here, these control boards already existed and were functional, so it would have been wasteful to throw them out. An easy improvement suitable for future projects would be to use NPN transistors to simulate button presses on the remote controls. This works quite well and lowers cost, power, and parts count, while being faster, more reliable, and quiet.

If you wanted to build something similar in your home or office, but want to use an Android smartphone instead of a touchscreen, the Kivy Python module allows you to do just that. It’s quite easy to set up a simple interface with buttons, dropdown lists, and text inputs that send data to an ESP8266 over UDP.

Mini Oscar Mayer Wienermobile Takes Moxie in KC

There are no shortage of fantastic and creative Power Racing Series cars, but here’s an especially fun example. [Pete Prodoehl] of Milwaukee Makerspace and his teammates [Kathy Cannistra] and [Kyle White] built a Power Racing car based on the design of the iconic Oscar Mayer Wienermobile.

They created the wienie and bun out of fiberglass and foam. Meanwhile, with the KC Maker Faire approaching, the team scrambled to finish the project, with [Kyle] working on assembly while [Pete] tackled the electronics. [Kyle] also proved to be the best wiener rider, with everyone else getting thrown off.

It should be noted that Milwaukee Makerspace got a Moxie bump because a wienermobile is on the PPPRS’s “hit list” of desirable designs. Anyone being the first to create a Top Gun F14, a Mystery Machine, or a non-DeLorean car from Back to the Future gets extra points.

If you like the Power Racing Series, you’ll be able to catch the wienermobile at both Maker Faire Detroit and Maker Faire Milwaukee. Also check out our posts on better racing with Power Wheels and checking a PPPRS car into baggage.

Possibly the Most Up-Cycled, Hacked E-Bike You’ll See All Week

When it comes to bringing an idea to life it’s best to have both a sense of purpose, and an eagerness to apply whatever is on hand in order to get results. YouTube’s favorite Ukrainians [KREOSAN] are chock full of both in their journey to create this incredible DIY e-bike using an angle grinder with a friction interface to the rear wheel, and a horrifying battery pack made of cells salvaged from what the subtitles describe as “defective smartphone charging cases”.

Battery pack made from cells salvaged out of defective equipment. Sometimes, you use what you have on hand.

What’s great to see is the methodical approach taken to creating the bike. [KREOSAN] began with an experiment consisting of putting a shaft on the angle grinder and seeing whether a friction interface between that shaft and the tire could be used to move the rear wheel effectively. After tweaking the size of the shaft, a metal clamp was fashioned to attach the grinder to the bike. The first test run simply involved a long extension cord. From there, they go on to solve small problems encountered along the way and end up with a simple clutch system and speed control.

The end result appears to work very well, but the best part is the pure joy (and sometimes concern) evident in the face of the test driver as he reaches high speeds on a homemade bike with a camera taped to his chest. Video is embedded below.

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DIY Electric Beach Luge is a Thrill

[John Dingley] describes his Electric Beach Luge Project as an exciting mashup between “a downhill luge board, a kite surf buggy, a go-kart, and a Star Wars Land Speeder” and it’s fresh from a successful test run. What’s not to like? The DIY experimental vehicle was made to run on long, flat, firm stretches of sand while keeping the rider as close to the ground as possible. The Beach Luge is mainly intended to be ridden while lying on one’s back, luge-style, but it’s also possible to lay prone in the “Superman” position.

The whole unit was built from the ground up, but [John] points out that the design isn’t particularly complicated. There is no fancy self-balancing or suspension involved and steering is simple. A tube bender and a welder took care of making the frame. The rest is mainly used go-kart parts obtained cheaply from eBay, driven by a 500W 24V electric motor from an old Golf Kart. Like a luge sled, the goal is for the vehicle itself to interfere as little as possible between the user and the earth to make the experience as visceral as it can be.

You can see it in action in the two videos embedded below, but even more videos and some great pictures are available on the project’s page. [John] says it’s great fun to ride, but feels it could use twice as much power!

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So, You’ve Never Made A Spaceframe Before

It is sometimes a surprise in our community of tinkerers, builders, hackers, and makers, to find that there are other communities doing very similar things to us within their own confines, but in isolation to ours. A good example are the modified vehicle crowd. In their world there are some epic build stories and the skills and tools they take for granted would not in any way be unfamiliar to most Hackaday readers.

As part of a discussion about electric vehicles near where this is being written, someone tossed an interesting link from that quarter into the mix; a two-part treatise on building ultra-light-weight tubular frame vehicles. Or space frames, as you might know them.

You might think that making a tubular framed for a vehicle would be a straightforward enough process, but as the article explains, it contains within it a huge well of geometry and metallurgy to avoid a creation that is neither too heavy nor contains excessive weakness. Part one deals mainly with prototyping a frame, the selection of materials and joining tubes, while part two goes into more detail on fabrication. The author likes brazing which may offend the sensibilities of welding enthusiasts, but you can substitute your jointing tech of choice.

A particularly neat suggestion, one of those simple ideas that make you wish you’d thought of it yourself, is to prototype a frame in miniature with copper wire and solder to evaluate the effect of different forces upon it before you commit your final design to steel.

The articles are a few years old, but no less pertinent in the information they contain. Meanwhile if you are a spaceframe veteran, then you may have your own suggestions for the comments below. And if you’d like some tips on how not to build a spaceframe, have a look at this motorcycle.

Thank you [JHR] and [Jarkman] for the tips.

Electric Longboard with All-New Everything

We love [lolomolo]’s Open Source electric longboard project. Why? Because he completely re-engineered everything while working on the project all through college. He tackled each challenge, be it electronic or mechanical as it came, and ended up making everything himself.

The 48″ x 13″ deck is a rather unique construction utilizing carbon fiber and Baltic birch. In testing the deck, [lolomol] found the deflection was less than an inch with 500 lbs. on the other end. He modified the Caliber II trucks to add four 2250W Turnigy Aerodrive brushless outrunners driving the wheels with the help of belts. The motors are controlled by VESC, an Open Source speed controller. There are a lot of fun details, like the A123 lithium cells equipped with custom battery management system PCBs.

The board sports 5W RGBW headlights that are so bright he can only run them at 10% PWM, plus RGB LED underlighting. All of it is controlled by an onboard Linux box. You can check out [lolomolo]’s GitHub repository for code, schematics, and CAD files. His Instructable for this project also has more design notes and thoughts.

If sweet longboards are your bag, check out the 3D-printed longboard and the long-distance electric longboard we published previously.