We say this with the greatest respect, but [Joel] — your exercise routine is horrible! Kudos for getting up and doing something, but 108 trips up and down the stairs? That sounds like torture, not exercise. Even [Joel] admits that it’s so boring that he loses count, and while we’d bet that he isn’t likely to restart the routine when that happens, it’s still annoying enough that he built this clever little lap counter to automate the task.
We kid, of course; any exercise is better than no exercise, and the stairs offer few excuses for skipping the daily workout. To bust the boredom problem, [Joel] toyed with a couple of ideas for toting up his laps before landing on a beam-break optical system with sensors at the top and the bottom of the stairs. Worried about the potential for false triggering by swinging arms and legs, he searched for ideas for bounceless switch circuits in the old “Engineer’s Notebook” by [Forrest Mims] and found a circuit close enough to modify for his needs. Each sensor setup has a high-output red LED and a phototransistor on one side of the stairwell, and a retroreflector on the opposite wall. Breaking the beam switches off the LED on that sensor and switches the other one on, to save on battery power.
The sensor’s flips and flops are counted and displayed on a three-digit seven-segment LED; [Joel] offers no detail on the counter itself, but with [Mims] as his muse, we suspect it’s something like the three-digit BCD counter circuit a few pages on from the bounceless switch circuit. The lap counter is shown in action in the brief video below.
That collective “Phew!” you heard this week was probably everyone on the Mars Ingenuity helicopter team letting out a sigh of relief while watching telemetry from the sixth and somewhat shaky flight of the UAV above Jezero crater. With Ingenuity now in an “operations demonstration” phase, the sixth flight was to stretch the limits of what the craft can do and learn how it can be used to scout out potential sites to explore for its robot buddy on the surface, Perseverance.
While the aircraft was performing its 150 m move to the southwest, the stream from the downward-looking navigation camera dropped a single frame. By itself, that wouldn’t have been so bad, but the glitch caused subsequent frames to come in with the wrong timestamps. This apparently confused the hell out of the flight controller, which commanded some pretty dramatic moves in the roll and pitch axes — up to 20° off normal. Thankfully, the flight controller was designed to handle just such an anomaly, and the aircraft was able to land safely within five meters of its planned touchdown. As pilots say, any landing you can walk away from is a good landing, so we’ll chalk this one up as a win for the Ingenuity team, who we’re sure are busily writing code to prevent this from happening again.
If wobbling UAVs on another planet aren’t enough cringe for you, how about a blind mechanical demi-ostrich drunk-walking up and down a flight of stairs? The work comes from the Oregon State University and Agility Robotics, and the robot in question is called Cassie, an autonomous bipedal bot with a curious, bird-like gait. Without cameras or lidar for this test, the robot relied on proprioception, which detects the angle of joints and the feedback from motors when the robot touches a solid surface. And for ten tries up and down the stairs, Cassie did pretty well — she only failed twice, with only one counting as a face-plant, if indeed she had a face. We noticed that the robot often did that little move where you misjudge the step and land with the instep of your foot hanging over the tread; that one always has us grabbing for the handrail, but Cassie was able to power through it every time. The paper describing how Cassie was trained is pretty interesting — too bad ED-209’s designers couldn’t have read it.
So this is what it has come to: NVIDIA is now purposely crippling its flagship GPU cards to make them less attractive to cryptocurrency miners. The LHR, or “Lite Hash Rate” cards include new-manufactured GeForce RTX 3080, 3070, and 3060 Ti cards, which will now have reduced Ethereum hash rates baked into the chip from the factory. When we first heard about this a few months ago, we puzzled a bit — why would a GPU card manufacturer care how its cards are used, especially if they’re selling a ton of them. But it makes sense that NVIDIA would like to protect their brand with their core demographic — gamers — and having miners snarf up all the cards and leaving none for gamers is probably a bad practice. So while it makes sense, we’ll have to wait and see how the semi-lobotomized cards are received by the market, and how the changes impact other non-standard uses for them, like weather modeling and genetic analysis.
Speaking of crypto, we found it interesting that police in the UK accidentally found a Bitcoin mine this week while searching for an illegal cannabis growing operation. It turns out that something that uses a lot of electricity, gives off a lot of heat, and has people going in and out of a small storage unit at all hours of the day and night usually is a cannabis farm, but in this case it turned out to be about 100 Antminer S9s set up on janky looking shelves. The whole rig was confiscated and hauled away; while Bitcoin mining is not illegal in the UK, stealing the electricity to run the mine is, which the miners allegedly did.
And finally, we have no idea what useful purpose this information serves, but we do know that it’s vitally important to relate to our dear readers that yellow LEDs change color when immersed in liquid nitrogen. There’s obviously some deep principle of quantum mechanics at play here, and we’re sure someone will adequately explain it in the comments. But for now, it’s just a super interesting phenomenon that has us keen to buy some liquid nitrogen to try out. Or maybe dry ice — that’s a lot easier to source.
The wheel is a revolutionary invention — as they say — but going back to basics sometimes opens new pathways. Robots that traverse terrain on legs are on the rise, most notably the Boston Dynamics Big Dog series of robots — and [Ghost Robotics]’ Minitaur quadruped aims to keep pace.
One of [Ghost Robotics] founders, [Gavin Knneally] states that co-ordination is one of the main problems to overcome when developing quadruped robots; being designed to clamber across especially harsh terrain, Minitaur’s staccato steps carry it up steep hills, stairs, across ice, and more. Its legs also allow it to adjust its height — the video shows it trot up to a car, hunker down, then begin to waddle underneath with ease.
How much access do you have to a 3D printer? What would you do if you had weeks of time on your hands and a couple spools of filament lying around? Perhaps you would make a two second stop-motion animation called Bears on Stairs.
An in-house development by London’s DBLG — a creative design studio — shows a smooth animation of a bear — well — climbing stairs, which at first glance appears animated. In reality, 50 printed sculptures each show an instance of the bear’s looping ascent. The entire process took four weeks of printing, sculpture trimming, and the special diligence that comes with making a stop-motion film.
This skateboard concept lets you travel down stairs almost as smoothly as gliding down a hill. This seems to be the eighth iteration in [PoChih Lai’s] attempts to add functionality to a board which will make it the ultimate ride for an urban outing. Check out the video after the break to see just how well he did.
We’ve seen hand carts that use six wheels to make stairs a breeze using a triad of wheels as a single-wheel replacement. This was actually the main concept early on in the design. But the drawback to this method is that the design takes up a lot of room and [PoChih] also made the deck much bulkier to keep you from getting a foot caught in the mechanism. The final design does away with the end-over-end concept and adopts a rocking mechanism. The board hangs from a bar which serves as the pivot between the two wheels. This way the wheels can absorb the brunt of the motions, and the base of the deck can slide across the fronts of the steps if needs be.
We were talking about this here at the Hackaday office and the point was made that this is like YT’s skateboard from Neal Stephenson’s Snow Crash. Did you hear that it’s headed to a theater near you?
We really like [Geert’s] take on accent lighting for his stairs. He built his own LED channels which mount under the bullnose of each step. The LED strips that he used are actually quite inexpensive. They are RGB versions, but the pixels are not individually addressable. This means that instead of having drivers integrated into the strip (usually those use SPI for color data) this strip just has a power rail and three ground rails for the colors. Ten meters of the strip cost him under forty dollars.
He did want to be able to address each step separately, as well as mix and match colors, so he designed the driver board seen above to use a set of TLC5940 LED drivers. These are controlled by the Arduino which handles color changing and animations. It will eventually include sensors to affect the LEDs as you walk up the stairs. Each strip is mounted in a piece of angle bracket, and they’re connected back to the driver board using telephone extension wire.
[Mike Li] is showing of his stair climbing robot. It’s a bot that cruises around on a pair of tank treads, but some interesting modifications gave him the traction needed to ascend a flight of stairs without slipping backward.
The image above shows this process in great detail. You can see the unaltered treads leaving the top of the image. In the foreground, strips of rubber-backed rug add some sticking power to the otherwise smooth surface. To really stop the bot from slipping, segments of CAT5 cable have been screwed to the tread at regular intervals, holding the carpeting tightly in the process.
You can see in the video after the break the little robot has no problem with rough terrain. The design was inspired by the iRobot Packbot which has a set of treaded appendages sticking off the front end. These ensure that the vertical face of an obstacle, such as the beginnings of a staircase, can still be reached by the main set of treads.
