Month: January 2020

DIY Autonomous Mower In The Wild

January 10, 2020 by 35 Comments

Mowing the lawn is one of those repetitive tasks most of us really wish we had a robot for. [Kenny Trussell] mowing needs are a bit more strenuous than most backyards, so he hacked a ride-on mower to handle multi-acre fields all on it’s own.

The mower started out life as a standard zero turn ride on lawn mower. It’s brains consist of a PixHawk board running Ardurover, an Ardupilot derivative for ground vehicles. Navigation is provided by a RTK GPS module that gets error corrections from a fixed base station via an Adafruit LoRa feather board, to achieve centimetre level accuracy. To control the mower, [Kenny] replaced the pneumatic shocks that centred the control levers with linear actuators.

So far [Kenny] has been using the mower to cut large 5-18 acre fields, which would be a very time-consuming job for a human operator. A relay was added to the existing safety circuit that only allows the mower to function when there is weight on the seat. This relay is wired directly to the RC receiver and is controlled from the hand-held RC transmitter. It will also stop the mower if it loses signal to the transmitter. To set up mowing missions, [Kenny] uses the Ardupilot Mission Planner for which he wrote a custom command line utility to create a concentric route for the mower to follow to completely cover a defined area. He has made a whole series of videos on the process, which is very handy for anyone wanting to do the same. We’re looking forward to a new video with all the latest updates.

This mower has been going strong for two years, but in terms of hours logged it’s got nothing on this veteran robotic mower that’s been at it for more than two decades and still runs off an Intel 386 processor.

A Luggable Computer For The Raspberry Pi Era

January 10, 2020 by 25 Comments

Today, computers are separated into basically two categories: desktops and laptops. But back in the early 1980s, when this ideological line in the sand was still a bit blurry, consumer’s had a third choice. Known as “portable computers” at the time, and often lovingly referred to as luggables by modern collectors, these machines were technically small enough to take with you on a plane or in the car.

Improvements in miniaturization ultimately made the portable computer obsolete, but that doesn’t mean some people still don’t want one. [Dave Estes] has been working on his own modern take on idea that he calls Reviiser, and so far it looks like it checks off all the boxes. With the addition of a rather hefty battery pack, it even manages to be more practical than the vintage beasts that inspired it.

In the video after the break, [Dave] walks us through some of the highlights of his luggable build, such as the fold-down mechanical keyboard, gloriously clunky mechanical power switches, and the integrated touch screen. We also really like the side-mounted touch pad, which actually looks perfectly usable given the largely keyboard driven software environment [Dave] has going on the internal Raspberry Pi 4. With a removable 30,000 mAh battery pack slotted into the back of the machine, he’ll have plenty of juice for his faux-retro adventures.

[Dave] mentions that eventually he’s looking to add support for “cartridges” which will allow the user to easily slot in new hardware that connects to the Pi’s GPIO pins. This would allow for a lot of interesting expansion possibilities, and fits in perfectly with the Reviiser’s vintage aesthetic. It would also go a long way towards justifying the considerable bulk of the machine; perhaps even ushering in a revival of sorts for the luggable computer thanks to hardware hackers who want a mobile workstation with all the bells and whistles.

Right now there isn’t a lot of detail on how you can build your own Reviiser, but [Dave] says more info will be added to his site soon. In the meantime, you can check out some of the similar projects we’ve seen recently to get some inspiration for your own Luggable Pi.

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HiFi Audio On The Commodore 64 – 48KHz, Yo!

January 9, 2020 by 34 Comments

Prior to the development of CD-quality audio hardware in the mid-1990s, home computers and consoles typically made do with synthesized music. Due to the storage and RAM limitations of the time, there weren’t a whole lot of other practical options. If you’re willing to ignore practicality, however, you can do some wonderful things – such as playing high-quality audio on a Commodore 64!

The project is the work of [Antonio Savona], who set out to play hi-fi audio on a Commodore 64 using only period-correct hardware. That means no 16MB RAM expansions, and no crazy high-capacity carts. The largest carts of the era were just 1MB, as produced by Ocean, and [Antonio] intended to cram in a full 90 seconds of music.

Targeting a sample rate of 48 KHz with 8-bit samples would mean the cartridge could only fit 20 seconds of raw audio into its 1MB of storage. This wasn’t good enough, so the audio would have to be compressed, with the target being a 4:1 ratio to reach the 90 second goal. With the C64’s CPU running at just 1MHz, there are just 21 clock cycles to deal with each sample when playing at 48 KHz.

Obviously, [Antonio] had set quite the challenge, and some masterful assembly coding was used to get the job done. The final result has the audio sounding impressively good, given that it’s being pumped out by a 6502 that is surely sweating to get the job done.

We love a good C64 hack around these parts, and it’s now even possible to build a new one from scratch if that’s your particular itch. Video after the break.

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Don’t DIY This Surgical Robot At Home

January 9, 2020 by 11 Comments

The LVL1 Hackerspace in Louisville hosted a hackathon for useless and impractical devices a couple of years ago and this makeshift Duh-Vinci Surgical Robot was one of the “successful” results. While it’s not necessarily a project that should ever be used for its intended purpose, its miniature setup is certainly an interesting one.

The project builds on top of the MeArm Open Source Robot and a camera controlled by a Blynk board. Servos are wired into the base of each of the robotic arms for freedom in rotating. A separate microcontroller is used for the motor controllers for the arms and for the camera, partially due to the current draw for the camera power supply. The remote control system runs on an Android tablet and is used to control each of the arms.

The ESP32-Cam supplied video input is configured as a RTSP stream. As for the operation, while the movements are jerky and the range of dexterity limited, the robot is technically able to handle the sharps. Its final setup looks a bit like a deranged game of Hungry Hungry Hippos meets Operation and definitely not something to be making its way to surgical tables anytime soon.

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Add-On Makes ESP32 Camera Board Easier To Program

January 9, 2020 by 16 Comments

Don’t you just hate it when dev boards have some annoying little quirk that makes them harder to use than they should be? Take the ESP32-CAM, a board that started appearing on the market in early 2019. On paper, the thing is amazing: an ESP32 with support for a camera and an SD card, all for less than $10. The trouble is that programming it can be a bit of a pain, requiring extra equipment and a spare finger.

Not being one to take such challenges lying down, [Bitluni] has come up with a nice programming board for the ESP32-CAM that you might want to check out. The problem stems from the lack of a USB port on the ESP32-CAM. That design decision leaves users in need of a USB-to-serial adapter that has to be wired to the GPIO pins of the camera board so that programs can be uploaded from the Arduino IDE when the reset button is pressed. None of that is terribly complex, but it is inconvenient. His solution is called cam-prog, and it takes care of not only the USB conversion but also resetting the board. It does that by simply power cycling the camera, allowing sketches to be uploaded via USB. It looks to be a pretty handy board, which will be available on his Tindie store.

To demonstrate the add-on, he programmed his ESP32-CAM and connected it to his enormous ping pong ball video wall. The video quality is about what you’d expect from a 1,200 pixel display at 40 mm per pixel, but it’s still pretty smooth – smooth enough to make his interpretive dance moves in the last few minutes of the video pretty interesting.

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Hiking Pole Turned Lightweight Yagi Antenna

January 9, 2020 by 10 Comments

Among amateur radio enthusiasts, there’s a subset of users who climb mountainous areas to use their gear from elevated positions. Anyone looking to take part in what’s known as Summits on the Air (SOTA) will obviously want to keep their equipment as light and small as possible. For [Stuart Thomas], that meant a collapsible yagi antenna he could easily pack away.

But one day he wondered why he was carrying around a separate antenna boom when his aluminum hiking pole would make a perfectly good substitute. All he had to do was figure out a way to mount the elements to the pole in a way that could be easily assembled in the field. He initially tried to use the sort of insulated electrical clamps used to hold down conduit, but he found they weren’t quite what he was after.

[Stuart] eventually ended up designing and 3D printing his own element mounts that use an M3 bolt to tightly clamp onto the hiking pole, preventing them from twisting while still being very lightweight and easy to adjust. To further reduce the packed size of the antenna, he cut each element in half with a pipe cutter and flared the ends slightly so he could reassemble them on location with inserts.

Even if you aren’t the type of person who owns hiking poles, let alone climbs mountains for fun, there’s still plenty of interesting applications for a lightweight yagi antenna. We’ve seen custom yagis built out of carbon fiber before and of course cobbling one together out of PVC and tape measures is a classic hack, but we think the solution [Stuart] has come up with strikes a nice balance between the extremes.

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Mini Space Station Keeps Tabs On The Real One

January 9, 2020 by 2 Comments

Over the years, we’ve seen a number of projects that can blink an LED or otherwise notify you when the International Space Station is overhead. It’s a neat trick that brings space a little closer to home, but not exactly a groundbreaking achievement in 2020. That said, we think this version built by [Lance] deserves some special recognition for the unbearably adorable miniature ISS he designed it around.

Especially once you realize that its tiny little solar panels are actually functional. Well, more or less. [Lance] says conditions have to be pretty ideal for the panels to actually charge up the internal battery, so there’s the option to top things off with a USB cable if need be. To try and reduce power consumption as much as possible, he uses some pretty aggressive power saving tricks which are interesting in their own right.

As the ISS silently passes over your head several times per day, the notifier can’t spend too much time sleeping on the job. The Particle Photon needs to wake up regularly to pull down the time of the next pass given the current geographical position, then go back to sleep until right before showtime. When the Station is nearby, it blinks an Adafruit Smart NeoPixel positioned under a small 3D printed model of the Earth, and finally goes back to sleep until the process starts over.

If you’re looking for something a little less complicated, this two dimensional representation of the Space Station might be more your speed. Then again, an even more complicated take on the idea using lasers sounds pretty good too.