Author: Danie Conradie

426 Articles

Litter Buggies Haul Trash Off The Beach

July 5, 2021 by 28 Comments

There is a depressing amount of trash in our oceans, and a lot of it is washes up on beaches. [Glenn Morris] has turned collecting all this trash into a favourite pastime, using a series of custom radio-controlled Litter Buggies to haul the load.

The most basic versions of these buggies are off the shelf RC rock crawlers, usually a Traxxas TRX-4, with a basket mounted in place of the body. However, [Glenn] has developed the buggies far beyond that, making extensive use of 3D printing to create purpose-built trash haulers. He has created several frame systems to hold removable baskets, buckets, lights and tools. Most of the buggies use lithium power tool batteries to allow quick swapping, and the electric motors, ESCs and gearing is selected for low speed and high torque. Since the buggies spend a lot of time exposed to salt water, almost all the steel hardware on the chassis are replaced with stainless steel. To allow for one handed control, [Glenn] attached 3D printed levers to the steering knobs of the standard RC controllers, allowing steering to be done with his thumb.

We really like what [Glenn] has been doing with these buggies, and think they might be a good platforms for adding some autonomous capabilities. Add a smartphone for target following or obstacle avoidance, or some solar panels and a GPS autopilot system.

Continue reading “Litter Buggies Haul Trash Off The Beach” →

Convert Your Mouse Into A Paddle Controller

July 4, 2021 by 4 Comments

Early game consoles had a wide and interesting variety of controllers, many of which fell by the wayside as consoles evolved. One of these is the Atari 2600 paddle controller, which was the preferred interface for playing games like Kaboom!, Tempest, and Pong.  While it is possible to play these games with a mouse, [Retro Gaming I Guess] wanted to do it the historically correct way, so he created a simple hack to convert an optical mouse into a paddle controller.

The main idea Is to attach a rotary knob to the bottom of the mouse, with the optical sensor located just inside the edge of the knob. To the optical sensor, it appears that the bottom surface of the knob is moving in a straight line, so the mouse pointer will move in a straight line as the knob rotates. The 3D printed knob (or bottle cap) is magnetically attached to the bottom of the mouse, by gluing one magnet into the center of the knob, and the other on the inside of the mouse under the PCB. This allows for quick conversion back to a normal mouse. You could off course sacrifice an old mouse to the cause to create a dedicated paddle controller, and make it closer to the original by adding end stops and a spring return.

We really like the simplicity of this hack, and we’re sure our readers can come up with a few other use cases for it in the comments below. You can also approach old Atari games from the opposite end, like adding a machine vision powered laser blaster. While many may think the Atari 2600 was the first gaming console, that honor actually goes to the Magnavox Odyssey, which was the start the of the multi-billion dollar home gaming industry we know today.

Extreme Canine Mask For Protection From Foxtails

July 4, 2021 by 33 Comments

Our canine partners are fortunately not affected by the current global pandemic, but it turns out there are other dangers that might necessitate them to wearing masks: Foxtail seeds. After getting a $400 vet bill for extracting a foxtail from his dog, [Hildeguard]’s ear, [Amos Dudley] decided to take the threat seriously and made her a form-fitting 3D printed mask.

The only commercial solution [Amos] could find was the “OutFox Field Guard”, which is a $50 vinyl-coated mesh bag that covers the dog’s entire head. It had the unfortunate side effects of causing some other dogs to try and rip it off and does not allow easy access to the mouth for treats or balls. [Hilde]’s custom mask was designed in CAD after creating a rough 3D scan of her head with an iPhone app. The bottom is open to allow [Hilde] to freely use her mouth, while the nose and ears holes are covered with mesh. Custom heat-formed polycarbonate lenses cover the eye holes. The mask itself was printed using Draft resin, and the inside was padded with a thin layer of foam. It might also be possible to create a silicone version using a 3D-printed mold. The top features an integrated GoPro mount, and we can’t help but wonder what other electronic upgrades could be fitted to this sci-fi-looking mask.

In the field, the mask worked well and did not seem to bother [Hilde]. Unfortunately, it did not solve the problem of other dogs trying to rip it off at the park, so for the moment [Amos] is only using it for more solitary activities like hiking.

It doesn’t look like [Amos] is struggling in that department, but if you need some help burning of your dog’s energy, you can always built them a 3D printed automatic ball launcher.

 

E-Ink Equipped Sourdough Starter Jar

July 3, 2021 by 2 Comments

One of the unexpected side effects of our this pandemic is a sudden growth in the global population of captive colonies of Lactobacillus bacteria and yeast. Also known as sourdough starters, they are usually found in jars with curious names written on top, living off a mixture of flour and water. They require close monitoring to keep them healthy and to determine when they are ready for baking. [Noah Feehan] has been working to instrument and automate the process for the past two years, and has created a high-tech jar to keep an eye on his sourdough starter.

For a sourdough starter to stay active, it must be kept within a certain temperature range, and performance is measured by how much the level inside the jar rises. Existing open source and commercial projects monitor these two parameters and transmit data out, but [Noah] wanted to include a few more features. The height of a sourdough starter rises due to the production of CO2, so he added an SCD-30 sensor module, which includes a temperature and humidity sensor. For level monitoring, an VL6180 time-of-flight sensor is mounted over a hole on top of the jar. [Noah] wanted to be able to see recent CO2 production and height stats right on the jar, a ESP32 module with onboard E-ink display was used. To draw air over the CO2 sensor at a constant rate, a small extraction fan was also added. Power is provided by a small LiPo battery. For long term logging, the data is sent over MQTT to a server running Mycodo environmental regulation software.

There are still several software improvements [Noah] would like to make, including battery life, user interface and alerts, but everything is open-source and available on GitHub, so feel free to jump in and build your own.

$10 000 Physics Wager Settles The Debate On Sailing Downwind Faster Than The Wind

July 2, 2021 by 95 Comments

By now, many of you have seen the video of [Rick Cavallaro]’s Blackbird, the controversial wind-powered land vehicle that can outrun the wind. The video has led to a high-profile $10 000 wager between [Derek Muller] aka [Veritasium] and [Alex Kusenko], a professor of physics from UCLA. [Veritasium] won the wager with the help of a scale model built by [Xyla Foxlin], and you need to watch the videos after the break for some excellent lessons in physics, engineering, and civilized debate.

After seeing [Veritasium]’s video on Blackbird, [Professor Kusenko] contacted him and said the performance claims and explanation were incorrect. After a bit of debate [Veritasium] proposed a wager on the matter, which [Professor Kusenko] accepted, and it was made official with a written agreement witnessed by [Neil deGrasse Tyson], [Bill Nye], and [Sean Carrol]. From the start, it was agreed that the entire debate would be made public.

[Professor Kusenko] made a very thorough and convincing argument, backed by calculations, against the claims in the video. He claimed the observations were due to a combination of gusty winds, a vertical wind gradient. He was convinced and that the vehicle would not be able to maintain a speed higher than the wind, directly downwind. By [Veritasium]’s own admittance, his original video could have contained more details and proof of performance claims of the Blackbird vehicle. He added these to the latest video and included two model demonstrations. The model that brought the concept home for us is at 13:46 in the video, and substitutes the propeller for a large wheel being driven by a piece of lumber being bushed across it. The second model, built by [Xyla Foxlin] was designed to demonstrate the concept on a treadmill. The 4th version of [Xyla]’s model was the first to be successful after she found out from [Rick Cavallaro] that the key design detail is the Vehicle Speed Ratio, which must be 0.7 or less. It is the pitch of the propeller divided by the circumference of the driven wheel, assuming a 1:1 gear ratio. All the 3D files and details are available if you want to build your own downwind cart. Continue reading “$10 000 Physics Wager Settles The Debate On Sailing Downwind Faster Than The Wind” →

A Robot To Top Up Your Tesla

July 2, 2021 by 37 Comments

The convenience of just plugging in your car in the evening and not going into a gas station is great as long as you remember to do the plugging. You really don’t want to get caught with an empty battery while you’re in a rush. [Pat Larson]’s Tesla plugging robot might be a handy insurance policy if you count forgetfulness among your weaknesses.

The robot consists of a standard Tesla charging plug attached to a 2-axis robotic arm mounted on [Pat]’s garage wall. Everything is controlled by a Python script running on Raspberry Pi 4. After taking a picture with a camera module, it uses a Tensor Flow Lite machine learning model to determine the position of a reflector on the charging port cover. The platform moves back and forth to align with the charging port, after which it opens the charging port using the Tesla API. It then extends the arm towards the charging port, using ultrasonic proximity sensors for distance control, and again uses the camera module and Tensor Flow to look for the illuminated Tesla logo adjacent to the charging port. The charge plug is flipped out using a large servo, and after some final position adjustment, it takes the plunge. While robot won’t be winning any interior design contests, it does the job well, and adds a bit of convenience and peace of mind.

Other Tesla hacks we’ve seen include building a working Model S for $6500, turning an old Honda into a speed demon using Tesla parts, and a Casio F-91W that can unlock your Tesla.

Dumping 90’s Honda ECU Programming With Arduino

July 2, 2021 by 19 Comments

[P1kachu] owns a pair of early 1990’s Honda’s with custom tuning on their stock ECUs, and after having to get the ECU repaired on his ’93 civic, he found himself going down the rabbit hole of Honda ECU EPROM chips.

During the repair process, the tuning shop owner, or [Tuner-san] as [P1ikachu] refers to him, made a backup of the custom tuning to another EPROM chip.  This was done with an old Advantest R4945A EPROM programmer, which [Tuner-san] supposedly also used to clone Famicom cartridges back in the day. After realizing that [Tuner-san] could only clone the contents, but not view or modify it, he started looking at ways to do that.

EPROMS are programmed using higher voltage (12.5 V – 25 V) but to read them 5 V is used. The memory address is selected by setting each of the 15 address pins high or low, and then reading the status of the 8 data pins to extract one byte of data. Rinse and repeat for each of the 256 memory addresses on the Microchip 27C256 EPROM. One of the previous owners of [Pikachu]’s Civic made some unknown tuning changes, so he is in the process of looking at the dumped data to see what was changed. Once he has completed figuring out the programming table of the EPROM, he plans to do some testing with [Tuner-san] to possible smooth out the rev limited.

An interesting aspect of EPROMs is that they are erased using UV light, which sets all the memory bits to 1. During programming, selected bits can be set to 0, but it’s not possible to set them back to 1 without erasing the entire chip again.

Messing around with the computers in cars is not only for tuning, but can also expose some rather serious security flaws, especially in modern vehicles.