Flipping a coin is often the initial example used to help teach probability and statistics to maths students. Often, there is talk of how, given a fair coin, the probability of landing heads or tails should approach 0.5. Of course, if you want to test this, it pays to have a machine do the hard work for you. [Andrew Consroe] has the rig to do just that.

The build consists largely of 3D printed parts. A large cylindrical shroud is used to keep the coin within the flipping area. A spring-loaded dowel is actuated by a stepper motor spinning a cam, which flips the coin. Once the coin has landed, it is photographed with a webcam. An image processing pipeline then determines whether the coin landed heads or tails. A black spot is used on one side of the coin to aid analysis, as the poor-quality webcam images weren’t good enough to recognise the coin in its standard form. Once the flip has been analysed, a sliding aperture is used to push the coin back towards the flipper for the next cycle.

The machine completes a flip approximately every two seconds, meaning 10,000 flips would take approximately 2.5 days. Unfortunately, due to noise and occasional coin escapes, [Andrew] hasn’t yet been able to achieve his goal. He aims to increase speed significantly before making an all-out attempt.

Coin flips can make for decent random numbers, but if you need better ones, perhaps NIST can help you out. Video after the break.

source https://hackaday.com/2020/07/21/flipping-a-coin-10000-times-with-a-dedicated-machine/

The Raspberry Pi HQ camera module is an exciting product that for the first time puts something close to a decent quality interchangeable lens camera into the hands of hardware hackers. It’s already attracted the attention of those who have a wish to explore the boundaries of camera form factors. Our latest entrant in this field comes courtesy of [BBまどーし], who has opted for a very good 3D-printed analog of a conventional compact camera.

On the front as you might expect is the module, concealed behind a smart plastic ring. Behind that is a battery compartment, concealing not the brace of 18650s or the bare LiPo pouch that you might expect, but a 10,400 mAH USB power bank. Behind that is something approaching a conventional Raspberry Pi case, designed to take a Hyperpixel screen. The battery might seem an unadventurous choice, but it serves to highlight just how much bang for your buck can now be found in compact power banks. It may not have a hacker aesthetic, but you can’t argue with its cost and simplicity.

The details are the interesting part of this design, for instance it has a standard accessory shoe printed into its top. There is also a shutter button, but they admit to not being a software wizard enough to get it working. Perhaps a quick look at this Pi Camera in a 1970s Merlin game would be in order.

source https://hackaday.com/2020/07/21/a-stylish-raspberry-pi-camera/

If you want to easily control the power in a circuit, you’ll probably reach for the classic toggle switch. While there’s certainly nothing wrong with that, physical toggles are a bit dated at this point. A soft power switch that turns your gadget on and off at the tap of a finger is far more 21st century. You might think this kind of modern trickery is too difficult to implement on a DIY project, but as [Sasa Karanovic] shows, it’s actually a lot easier than you might think.

Now to be fair, that wasn’t actually his goal. All [Sasa] was trying to do was come up with a slick way to control the LED lighting in his 3D printer enclosure. Which, as you can see in the video below, he accomplished. But the hacked together circuit he used to do it could easily be adapted for other electronic projects. If you’re using a LM2596 DC-DC converter module to power your gadget, you can add a touch sensitive soft switch for literally pennies.

The trick is utilizing the enable pin on the LM2596. The common buck converter modules tie this pin to ground so the regulator is always enabled, but if you lift the pin off the PCB and connect it to the output of a TTP223 capacitive touch sensor, you can simply tap the pad to control the regulator. Power for the touch sensor itself is pulled from the input side of the regulator, so even when the power is cut off downstream, the sensor is still awake and can kick the chip back into gear when you need it.

If you’re not interested in touch control, you could try connecting the enable pin on the regulator to an ESP8266 and making a cheap Internet-controlled DC power supply.

source https://hackaday.com/2020/07/21/a-simple-soft-power-switch-using-common-modules/

Gears of War is a franchise famous for its giant gun with a big chainsaw on the front. [Eric] laid his hands on a toy replica, and decided it had to become a usable motion controller for the game.

The build is straightforward, following the usual format for motion controller builds. Fitted with a gyroscope and accelerometer, it’s interfaced to the PC using a microcontroller. The toy has a trigger which is hooked up to the fire button in game. Additional buttons were added to the shell for movement and other actions such as reloading and finding cover. As a nice final touch, the large pull handle on the left of the weapon is used to activate the chain saw in-game.

While it’s unlikely to be competitive with a mouse or even gamepad in practice, it’s hard to argue against the fun of wielding a full-size, 10-pound weapon when playing Gears of War 5. [Eric] has also shared a basic controller hacking guide for those eager to get into similar builds themselves. We’ve featured [Eric]’s work before, too – with this epic Minecraft pickaxe build. Video after the break.

source https://hackaday.com/2020/07/20/life-size-lancer-becomes-gears-of-war-motion-controller/

3D printed parts are generally no way near the strength of an equivalent injection moulded part and techniques such as a sustained heat treatment, though effective usually distort the part beyond use.

[CNC Kitchen] was investigating the results of a recent paper, that described a novel ABS filament reinforced by a “star” shaped Polycarbonate core, an arrangement the authors claim is resilient to deformation during the annealing process often necessary to increase part strength. While the researchers had access to specialised equipment needed to manufacture such a composite material, [CNC Kitchen’s] solution of simply using his dual extruder setup to directly print the required hybrid filament is something we feel, strongly resonates with the now old school, RepRap “print your printer” sentiment.

The printed filament seems to have reasonable dimensional accuracy and passing the printed spool through a heater block without the nozzle attached, ensured there would be no obvious clogs. The rest of the video focuses on a very thorough comparison of strength and deformation between the garden variety Polycarbonate, ABS and this new hybrid filament after the annealing process. Although he concludes with mixed results, just being able to combine and print your own hybrid filament is super cool and a success in its own right!

Interested in multi-material filaments? Check out our article on a more conventional approach which does not involve printing it yourself!

source https://hackaday.com/2020/07/20/can-a-3d-printer-print-better-filament-for-itself/

Bowling is great and all, but the unpredictability of that little ball jump in Skee-Ball is so much more exciting. You can play it straight, or spend a bunch of time perfecting the 100-point shot. And unlike bowling, there’s nothing to reset, because gravity gives you the balls back.

In one of [gcall1979]’s earlier Skee-Ball machines, gravity assisted the scoring mechanism, too: each ball rolls back to the player and lands in a lane labeled with the corresponding score, which is an interesting engineering challenge in its own right. He decided to build automatic scoring into his newest Skee-Ball machine.

At the bottom of each cylinder is an arcade machine coin door switch with a long wire actuator. These had to be mounted so they’re close enough to the hole, but out of the way of the balls.

Each switch is wired up to an Arduino Mega along with four large 7-segments for the score, and a giant 7-segment to show the number of balls played. Whenever the game is reset, a servo drops a door to release the balls, just like a commercial machine.

The arcade switches work pretty well, especially once he bent the wire into hook shape to cover more area. But they do fail once in a while, maybe because the targets are full-size, but the balls are half regulation size. For the next one, [gcall1979] is planning to use IR break-beam targets which ought to work with any size ball. If you prefer bowling, you won’t strike out with break-beam targets there, either.

source https://hackaday.com/2020/07/20/skee-ball-scoring-with-coin-slot-switches/

Minecraft is a game about exploring procedure-generated worlds. Each world is generated from a particular “seed” value, and sharing this seed value allows others to generate the same world in their own game. Recently, the distributed computing project Minecraft@Home set about trying to find the seed value of the world shown in the Minecraft title screen, and have succeeded in their goal.

The amount of work required to complete this task should not be underestimated. 137 users contributed 181 hosts with 231 GPUs to the effort, finding a solution in under 24 hours. The list of contributors to the project is a long one. It appears the method to find the seed involved comparing screenshots from various seed worlds to the original image. This took a lot of reverse engineering in order to calculate the camera FOV and other settings of the original capture, such that the results could be compared accurately. Interestingly, the group found two seeds that can generate the requisite world, suggesting the world generator code has some collisions between seed values.

We’re not sure what’s more astounding, the amount of work that went into the project, or that there’s a distributed computing project tackling advanced Minecraft research. Either way, we’re no strangers to Minecraft hacks around these parts. Video after the break.

source https://hackaday.com/2020/07/20/finding-the-random-seed-of-minecrafts-title-screen/