Retired Rideshare Scooter Skips The Reverse Engineering To Ride Again

March 19, 2019 by Donald Papp 7 Comments

[Adam Zeloof] (legally) obtained a retired electric scooter and documented how it worked and how he got it working again. The scooter had a past life as a pay-to-ride electric vehicle and “$1 TO START” is still visible on the grip tape. It could be paid for and unlocked with a smartphone app, but [Adam] wasn’t interested in doing that just to ride his new scooter.

His report includes lots of teardown photos, as well as a rundown of how the whole thing works. Most of the important parts are in the steering column and handlebars. These house the battery, electronic speed controller (ESC), and charging circuitry. The green box attached to the front houses a board that [Adam] determined runs Android and is responsible for network connectivity over the cellular network.

To get the scooter running again, [Adam] and his brother [Sam] considered reverse-engineering the communications between the network box and the scooter’s controller, but in the end opted to simply replace the necessary parts with ones under their direct control. One ESC, charger, and cheap battery monitor later the scooter had all it needed to ride again. With parts for a wide variety of electric scooters readily available online, there was really no need to reverse-engineer anything.

Ridesharing scooter startups are busy working out engineering and security questions like how best to turn electric scooters into a) IoT-connected devices, and b) a viable business plan. Hardware gets revised, and as [Adam] shows, retired units can be pressed into private service with just a little work.

The motors in these things are housed within the wheels, and have frankly outstanding price-to-torque ratios. We’ve seen them mated to open-source controllers and explored for use in robotics.

Spotting Scope Mount Makes For More Comfortable Target Scoring

March 16, 2019 by Donald Papp 15 Comments

One of the big bottlenecks in target shooting is the scoring process. Even if it’s not a serious match, it’s still important to know where holes have landed because it’s important feedback on technique and performance. A spotting scope, which is really just a kind of telescope optimized for getting a sharp view of a distant target, is often used to see hits on a target without leaving the firing line. Usually they’re mounted on tripods and optimized for seated use, but [Steve Thone] came up with a clever hack for more comfortable use and mounting that works better for him while engaging in bulls-eye shooting from the standing position.

[Steve] took a ratcheting bar clamp and drilled a few holes near the end of the bar. Using these holes, the spotting scope is mounted directly to the bar and the clamp grips a shooting table or bench in place of a stand. He also put a 90 degree twist in the bar so that the clamp and scope could be oriented perpendicular to one another.

The result is a quick and easy-to-use mounting solution that, unlike a tripod, doesn’t eat up precious table space. Stability may be inferior to a tripod, but it’s serviceable enough that other shooters showed up with their own versions the week after [Steve] used his. After all, target shooters tend to be DIY types with an interest in both low-tech hacks like this one as well as higher-tech projects like rifle-mounted sensors.

Wood SCARA Arm Gets A Grip

March 14, 2019 by Donald Papp 4 Comments

[Ignacio]’s VIRK I is a robot arm of SCARA design with a very memorable wooden body, and its new gripper allows it to do a simple pick and place demo. Designing a robot arm is a daunting task, and the fundamental mechanical design is only part of the whole. Even if the basic framework for a SCARA arm is a solved problem, the challenge of building it and the never-ending implementation details make it a long-term project.

When we first saw VIRK I in all its shining, Australian Blackwood glory, it lacked any end effector and [Ignacio] wasn’t sure of the best way to control it. Since then, [Ignacio] has experimented with Marlin and Wangsamas support for SCARA arms, and designed a gripper based around a hobby servo. It’s as beautiful to see this project moving forward as it is to see the arm moving ~~ping-pong~~ balls around, embedded below.

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Watch This LEGO Pantograph Carve Chocolate Messages

March 7, 2019 by Donald Papp 5 Comments

[Matthias Wandel] is best known for his deeply interesting woodworking projects, so you might be forgiven for not expecting this lovely chocolate-engraving pantograph made from LEGO. With it, he carves a delightful valentine’s message into a square of chocolate, but doesn’t stop there. He goes the extra mile to cut the chocolate carefully into a heart, and a quick hit with a heat gun takes the rough edges off for a crisp and polished end result.

The cutting end is a small blade stuck inside a LEGO piece, but that’s the only non-LEGO part in the whole assembly. A key to getting a good carve was to cool the chocolate before engraving, and you can see the whole process in the video embedded below.

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Justin McAllister’s Simple, Post-Apocalypse-Friendly Antennas

March 4, 2019 by Donald Papp 10 Comments

Watch Justin McAllister’s presentation on simple antennas suitable for a zombie apocalypse and two things will happen: you’ll be reminded that everything antennas do is amazing, and their reputation for being a black magic art will fade dramatically. Justin really knows his stuff; there is no dangle-a-wire-and-hope-for-the-best in his examples. He demonstrates that it’s possible to communicate over remarkable distances with nothing more than an off-the-shelf radio, battery pack, and an antenna of simple design.

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Spot This DIY Electronic Load’s Gracefully Hidden Hacks

February 28, 2019 by Donald Papp 11 Comments

Sometimes it’s necessary to make do with whatever parts one has on hand, but the results of squashing a square peg into a round hole are not always as elegant as [Juan Gg]’s programmable DC load with rotary encoder. [Juan] took a design for a programmable DC load and made it his own in quite a few different ways, including a slick 3D-printed enclosure and color faceplate.

The first thing to catch one’s eye might be that leftmost seven-segment digit. There is a simple reason it doesn’t match its neighbors: [Juan] had to use what he had available, and that meant a mismatched digit. Fortunately, 3D printing one’s own enclosure meant it could be gracefully worked into the design, instead of getting a Dremel or utility knife involved. The next is a bit less obvious: the display lacked a decimal point in the second digit position, so an LED tucked in underneath does the job. Finally, the knob on the right could reasonably be thought to be a rotary encoder, but it’s actually connected to a small DC motor. By biasing the motor with a small DC voltage applied to one lead and reading the resulting voltage from the other, the knob’s speed and direction can be detected, doing a serviceable job as rotary encoder substitute.

The project’s GitHub repository contains the Arduino code for [Juan]’s project, which has its roots in a design EEVblog detailed for an electronic load. For those of you who prefer your DIY rotary encoders to send discrete clicks and pulses instead of an analog voltage, a 3D printed wheel and two microswitches will do the job.

Multiple OLEDs? Save Pins By Sharing The I2C Clock

February 27, 2019 by Donald Papp 17 Comments

Inexpensive OLED displays with I2C interfaces abound, but there is a catch: they tend to be stuck on I2C address 0x3C. Some have a jumper or solder pads to select an alternate (usually 0x3D), but they lack any other method. Since an I2C bus expects every device to have a unique address, this limits the number of displays per bus to one (or two, at best.) That is all still true, but what [Larry Bank] discovered is a way to get multiple OLED displays working with considerably fewer microcontroller pins than usually needed.

While bit-banging I2C to host one display per bus on the same microcontroller, an idea occurred to him. The I2C start signal requires both clock (SCL) and data (SDA) to be brought low together, but what would happen if the displays shared a single clock line? To be clear, each OLED would — logically speaking — still be on its own I2C bus with its own data line, but they would share a clock signal. Would a shared clock cause attached devices to activate unintentionally?

A quick test consisting of four OLED displays (all with address 0x3C) showed that it was indeed possible to address each display with no interference if they shared a clock. Those four individually controlled displays needed only five I/O lines (four SDA, one shared SCL) instead of eight. The Multi_OLED library is available on GitHub, and in case it is useful for devices other than OLED displays, bit-banged I2C with support for shared clock lines is available separately.

There’s more to do with OLEDs than get clever with signals: check out these slick number-change animations, and that even looks to be a project that could benefit from a few saved GPIO pins, since it uses one small display per digit.