[RCLifeOn] happened upon an old petrol-powered ATV that had seen better days. He decided it was the perfect candidate for a conversion to electric drive.
First up, the chassis was stripped back and cleaned, before being given a fresh coat of paint. It then got fresh valve stems for the tires and was ready for its drivetrain conversion.
The motor of choice is a brushless type, rated for 42 kW at 120 V. [RCLifeOn] doesn’t have batteries capable of maxing out those specs, yet, but carried on with the build. The motor was mounted on the chassis, and a 3D printed hub was installed to get the sprocket on the end of the motor.
The first drive was rough and ready, as the speed controller wasn’t sensored, the gearing wasn’t quite right, and the chain wasn’t very tight. However, it did successfully make it around the grass, slowly. Further improvements then included a water cooling circuit for the speed controller and the addition of a battery compartment. That wasn’t enough to stop the speed controller bursting into flames during a difficult uphill climb, though.
Fundamentally, though, the project shows promise. Bigger batteries, a sensored speed controller, and appropriate gearing should make it a quick beast. 42 kW of power is a good amount for a light ATV, plus there’s the benefit of instant-on torque from an electric motor.
We’ve seen [RCLifeOn] tackle some high-powered electric builds before, like his impressive powered surfboard. With the right parts, we’re sure he’ll have this thing ripping about at pace before long!
When most of us approach a project, we have a certain problem to solve. 3D printing, microcontrollers, batteries, and all kinds of technologies are usually tools to accomplish some task. This is not necessarily true in the art world, though, where the intrinsic nature of these tools can be explored for their own sake rather than as a means to an end. The latest one that came across our desk is this light-powered sound generator.
The art piece looks a bit like a mobile with rotating arms, holding various small solar cells each connected to a speaker. As the arms pivot, the light falling on the cells changes which drives a specially-designed circuit connected to a speaker. The circuit acts as an oscillator, passing the changing voltage from the cell through various capacitors and transistors to produce changing tones in the speaker.
The effect of the rotating solar panels is not only oscillations from the speakers as the light changes, but oscillations in the sound of the speakers as they rotate towards and away from the observer. It’s a unique project and perfect for the art show it was in. It’s also not the only sound-focused art installation we’ve ever seen before, be sure to check out this one based on an ESP32.
First attempts involved heating in a microwave or chilling the cookies in the freezer. Neither helped in the slightest. A vacuum chamber only served to delaminate the cream from both sides of the cookie entirely, while water jet cutting made an awful mess.
[Ian] ended up realizing that crack propagation could be used to prepare Oreos for a perfect split. A knife was used to score a groove all around the cream layer, right down the middle. The Oreos were then frozen, turning the cream effectively solid. When the Oreo is then twisted, the groove serves as a starting point for a crack that propagates across the surface, splitting the cream neatly between both halves.
[Ian] took things further by building a 3D-printed lathe that grooves Oreos using a sterilized scalpel blade. This allows cookies to be quickly prepped for a perfect split. However, you are left eating frozen Oreos at the end of it, with some sacrifices to freshness.
It’s a neat way to approach the Oreo splitting problem, even if it’s only one step removed from simply using a knife. We’ve seen [Ian]’s work before, too, in the form of the radioactively-powered Game Boy. Video after the break.
While on the search for an alternative to directly buying the fairly expensive MH-Z19 CO2 sensor, [spezifisch] came across a ‘BreeRainz’ branded gadget (also found under other brands) that claimed to use an NDIR (Non-Dispersive Infrared) sensor for measuring CO2 levels, while costing only €25. This type of sensor allows for CO2 levels to be measured directly, rather than inferred, making them significantly more precise.
After cracking the gadget open (literally, due to the hidden screws), the CO2 sensor is clearly visible. While superficially identical to an MH-Z19, the NDIR sensor is actually called ‘HC8’, is produced by 广州海谷电子科技有限公司 (Guangzhou Haigu Electronic Technology Co., Ltd.). While being pin-compatible with the MH-Z19, its UART protocol is not the same. Fortunately there is a datasheet to help with implementing it, which is what [spezifisch] did.
This raises the question of whether harvesting NDIR CO2 sensors like this is worth it to save a few Euros. A quick look on German Amazon shows that the device in question currently costs €35, while a genuine MH-Z19 can be bought for €25 or less. There are also many MH-Z19 models (B, C and D), which cover an even wider price range. All of which points to finding an NDIR sensor-containing device can be interesting when it’s on sale, but if all you care about is the sensor itself, it’s probably best to just buy them directly.
Sun Chaser is essentially a robotic solar panel, tasked with filling up its batteries as much as possible. It can then be used as a power supply for campsites or other remote areas, and used to charge devices as required.
A Raspberry Pi runs the show, paired with a Squid motor controller to run the drive system. Sun Chaser has a motorized solar panel onboard which can track the sun for maximum output, with the aid of six photoresistors to guide the positioning. A camera is used to image the area around Sun Chaser, too, and processing is used to identify sunny regions which will provide the most energy.
If your friend told you their car had a backup camera, a digital dashboard, climate control, could scan for radio stations, and even helped stay on the road, you wouldn’t think much about it. Unless the year was 1969. The car — the Hurricane by Australian automaker Holden — was never a production vehicle. But it was way beyond the state of the art in 1969 and isn’t too dated, even today. The concept car was actually found in 1988 and restored by 2011. Honestly, it still looks great.
The car looks amazing and was meant to be a research vehicle and — probably — nice eye candy for the car shows. Seating two passengers with a mid-mounted 253 cubic inch V8, it featured many things we take for granted now: a backup camera, temperature control, and a (somewhat) digital dashboard, for example. There was a system to help it stay in lane, but that required magnets in the road — it was 1969, after all.
The fiberglass body was unique and had a canopy instead of doors. The power seats lifted up when the canopy came up and went down for driving. The passenger compartment was a steel cage. The vehicle featured headrests, a foam-lined fuel tank, and a fire warning system. Two of the brakes were even oil-cooled.
When interfacing with the real world, there are all kinds of sensors available which will readily communicate with your microcontroller of choice. Moisture, pH, humidity, temperature, location, light, and essentially every other physical phenomenon are readily measured with a matching sensor. But if you don’t have the exact sensor you need, it’s sometimes possible to use one sensor as a proxy for another.
[Brian Wyld] needed a way to monitor the level of a remote body of water but couldn’t use a pressure or surface-level sensor, so he used a sensor typically intended for geolocation instead. This particular unit, an STM-type device with a built-in accelerometer, is attached to a rotating arm with a float at one end. As the arm pivots, the microcontroller reports its position and some software converts the change in position to a water level. It’s also paired with a LoRa radio, allowing it to operate off-grid.
Whether there is a design requirement to use an esoteric sensor to measure something more common, or a personal hardware limitation brought about by a shallow parts drawer, there’s often a workaround like this one that can accomplish the job. Whatever the situation, we do appreciate hacking sensors into other types of sensors just as much as anything else.