Author: Danie Conradie

427 Articles

Open Source CAM Software In The Browser

March 1, 2021 by 24 Comments

3D printers, desktop CNC mills/routers, and laser cutters have made a massive difference in the level of projects the average hacker can tackle. Of course, these machines would never have seen this level of adoption if you had to manually write G-code, so CAM software had a big part to play. Recently we found out about an open-source browser-based CAM pack created by [Stewert Allen] named Kiri:Moto, which can generate G-code for all your desktop CNC platforms.

To get it out of the way, Kiri:Moto does not run in the cloud. Everything happens client-side, in your browser. There are performance trade-offs with this approach, but it does have the inherent advantages of being cross-platform and not requiring any installation. You can click the link above and start generating tool paths within seconds, which is great for trying it out. In the machine setup section you can choose CNC mill, laser cutter, FDM printer, or SLA printer. The features for CNC should be perfect for 90% of your desktop CNC needs. The interface is intuitive, even if you don’t have any previous CAM experience. See the video after the break for a complete breakdown of the features, complete with timestamp for the different sections.

All the required features for laser cutting are present, and it supports a drag knife. If you want to build an assembly from layers of laser-cut parts, Kiri:Moto can automatically slice the 3D model and nest the 2D parts on the platform. The slicer for 3D printing is functional, but probably won’t be replacing our regular slicer soon. It places heavy emphasis on manually adding supports, and belt printers like the Ender CR30 are already supported.

Kiri:Moto is being actively improved, and it looks as though [Stewart] is very responsive to community inputs. The complete source code is available on GitHub, and you can run an instance on your local machine if you prefer to do so. Continue reading “Open Source CAM Software In The Browser” →

Shredding The Ice With Powered Skates

March 1, 2021 by 9 Comments

The availability of small and powerful brushless motors has been instrumental in the development of so-called micro-mobility vehicles. But if your commute involves crossing a frozen lake, you might find the options a bit lacking. Fortunately [Simon] from [RCLifeOn] now has a solution for you in the form of motorized ice skates.

[Simon] used 3D printed brackets to mount outrunner brushless motors to the back of a pair of ice-skates. The spinning outer housing of the motor is used as the wheel, with a bunch of studs threaded in it to dig into the ice and provide traction. At first [Simon] tried to use a pair of RC car springs to keep the motor in contact with the ice, but spring force was insufficient for the task, so he ended up rigidly mounting the motors. Getting proper traction on the ice from a standstill was still tricky, so he ended up leaning back to push the motor down, which also had the effect of putting him off balance, limiting the practical acceleration. The most obvious solution for the tracking problem seems to be stronger springs, but we assume he didn’t have any on hand. The batteries are held in a backpack, with cables running down to the skates, and a wireless electric skateboard controller is used for throttle control.

The obvious risk of these skates is of the studded motors inadvertently becoming meat grinders if you fall. It still looks like a fun project, and we wouldn’t mind having a go on those skates.

[Simon] likes messing around with brushless motors, and has done everything from a jet-powered surfboard to a gyro-stabilized RC “motorbike”.

Continue reading “Shredding The Ice With Powered Skates” →

Hidden TV-Out On The Nintendo DS Lite

February 28, 2021 by 34 Comments

The DS Lite was one of Nintendo’s most popular handheld gaming consoles, but unbeknownst to all, it has a hidden feature that could have made it even more popular. Digging through the hardware and firmware, the [Lost Nintendo History] team discovered the System-on-Chip (SoC) in the DS Lite can output a composite video signal.

The SoC can output a 10-bit digital output running at 16.7 MHz, but it is disabled by the stock firmware early in the boot process, so custom firmware was required. It still needs to be converted to an analog signal, so a small adaptor board with a DAC (digital-analog converter) and op-amp is attached to the flex cable of the upper screen. A set of buttons on the board allow you to select which screen is displayed on the TV. The adaptor board is open source, and the Gerbers and schematics are available on GitHub.

The current version of the adaptor board disables the upper screen, but the [Lost Nintendo History] team is considering designing a pass-through board to eliminate this disadvantage. The TV-out mod can also be combined with the popular Macro mod, in which the upper screen is removed to turn it into a Game Boy Advance. The Nintendo DS is a popular hacking subject, and we’ve been covering them for well over a decade.

Pool Noodle Robot Shines A Light On The Pros And Cons Of Soft Robots

February 27, 2021 by 4 Comments

[James Bruton]’s impressive portfolio of robots has always used conventional rigid components, so he decided to take a bit of a detour and try his hand at a soft robot. Using a couple of few inflatable pool noodles for quick prototyping, his experiments quickly showed some of the strengths and weaknesses of soft robots.

Most of the soft robots we see require an external air source to inflate cells in the robot and make the limbs actuate. Taking inspiration from a recent Stanford research project, [James] decided to take an alternative approach, using partially inflated tubes and squeezing them in one section to make the other sections more rigid. He bought a couple of cheap pool noodles and experimented with different methods of turning them into actuators. The approach he settled on was a pair of noodles tied together side by side, and then folded in half by an elastic cord. As one end is squeezed by a servo bellows, the internal pressure overcomes the tension from the elastic cord, and the “elbow” straightens out.

[James] tested various arrangements of these limbs to build a working hexapod robot but to no avail. The simple actuating mechanism was simply too heavy, and could just lift itself slightly. This highlighted a common theme in almost all the soft pneumatic robots we’ve seen: they carry very little weight and are always tethered to an external air supply. The combination of stretchy materials and relatively low pressure compressed air can only handle small loads, at least in Earth gravity and above water. Continue reading “Pool Noodle Robot Shines A Light On The Pros And Cons Of Soft Robots” →

Electric Airboat For Getting You Across Thin Ice

February 25, 2021 by 20 Comments

Even with all the technological progress civilization has made, weather and seasons still have a major impact on our lives. [John de Hosson] owns a cabin on an island in a Swedish lake, and reaching it involves crossing 500 m of water. In summer this is done with a conventional boat, and in winter they can simply walk across the thick ice, but neither of these is an option on thin ice in the spring or fall. To solve this [John] built an electric airboat, and it looks like a ton of fun in the video after the break

The construction is simple but functional. A 3.3 m flat-bottomed aluminum boat has used a base, and an aluminum frame was bolted on for the motor and propeller. The motor is an 18 kW brushless motor, with a 160 cm/63-inch carbon fiber propeller. Power comes via a 1000 A ESC from a 100V 3.7 kWh Lipo pack mounted in a plastic box. Steering is very similar to a normal airboat, with a pair of air rudders behind the propeller, controlled by a steering lever next to the driver’s seat. The throttle is an RC controller with the receiver wired to the ESC.

Performance is excellent, and it accelerates well on ice and slush, even with two people on board. [John] still plans to make several improvements, with a full safety cage around the propeller being at the top of the list. He is also concerned that it will capsize on the water with the narrow hull, so a wider hull is planned. [John] has already bought a large steering servo to allow full remote control for moving cargo, with the addition of an FPV system. We would also add an emergency kill switch and waterproofing for the electronics to the list of upgrades. It looks as though the battery box is already removable, which is perfect for getting it out of the cold when not in use.

Continue reading “Electric Airboat For Getting You Across Thin Ice” →

Demonstrating The Mars Rover Pendulum Problem With A Drone On Earth

February 25, 2021 by 39 Comments

The sky crane system used on the Perseverance and Curiosity Mars rovers is a challenging control system problem that piqued [Nicholas Rehm]’s curiosity. Constrained to Earth, he decided to investigate the problem using a drone and a rock.

The setup and the tests are simple, but clearly illustrate the problem faced by NASA engineers. [Nicholas] attached a winch mechanism to the bottom of a racing-type quadcopter, and tied a mass to the end of the winch line. At first, he built a foam model of the rover, but it proved to be unstable in the wake of the quadcopter’s propellers, so he used a rock instead. The tests start with the quadcopter taking off with the rock completely retracted, which is then slowly lowered in flight until it reaches the end of the line and drops free. As soon as the rock was lowered, it started swinging like a pendulum, which only got worse as the line got longer. [Nicholas] attempted to reduce the oscillations with manual control inputs, but this only made it worse. The quadcopter is also running [Nicholas]’s own dRehmFlight flight controller that handles stabilization, but it does not account for the swinging mass.

[Nicholas] goes into detail on the dynamics of this system, which is basically a two-body pendulum. The challenges of accurately controlling a two-body pendulum are one of the main reasons the sky crane concept was shelved when first proposed in 1999. Any horizontal movement of either the drone or the rock exerts a force on the other body and will cause a pendulum motion to start, which the control system will not be able to recover from if it does not account for it. The real sky crane probably has some sort of angle sensing on the tether which can be used to compensate for any motion of the suspended rover. Continue reading “Demonstrating The Mars Rover Pendulum Problem With A Drone On Earth” →

DIY USB-C Touch Monitor Is All Polished Brass

February 25, 2021 by 17 Comments

We’ve known for a while that you can buy interface boards to turn old laptop screens into standalone monitors, but complete sets with 4K panels and control boards are also now becoming widely available on sites like eBay and AliExpress, and prices are dropping. These sets are also available with low-profile connectors like micro HDMI and USB-C, which allow for some very compact builds.

[Matt] from [DIY Perks] used one of these sets to build a slimline USB-C monitor with a brass enclosure. Video after the break. The enclosure consists of brass sheets and U-channel pieces soldered and screwed together. There is quite a bit of residue and discoloration after soldering, but this was removed with a bit of sanding and polishing. A pair of adjustable legs were added to allow it to stand on its own, and an additional chamber on the back holds the control board, an old smartphone battery, and a battery protection circuit. [Matt] also added a pair of removable speakers, which are sealed speaker units covered in brass mesh and plate.

We’ve covered several DIY monitor builds over the years, and they are perfect as an additional monitor for a laptop, or for pairing with the Raspberry Pi 400 with its integrated keyboard. We really [Matt]’s builds, which include a smartphone-based 4K projector, and a very effective cooling system for an expensive DSLR camera. Continue reading “DIY USB-C Touch Monitor Is All Polished Brass” →