A Simple Touch Probe Made With Basic Tools

January 5, 2022 by Dave Rowntree 14 Comments

Six points of contact detect any displacement.

LinuxCNC contributor and machining enthusiast [Andy Pugh] is certainly not afraid to try making specialised tools to see how well they work out, and this time he’s been busy making a touch probe (video, embedded below) for checking the accuracy of machining operations and general measuring applications.

These things are not cheap, since they are essentially ‘just’ a switch with a long probe, But, as with anything specialised and machined with tight tolerances, you can understand why they cost what they do.

After inspecting and spending some time reverse-engineering such a unit, [Andy] then proceeded to grab some PEEK bar he had lying around and chuck it into the lathe (get it?). He notes Delrin would be more cost effective for those wishing to reproduce this, but as long as you have the ability to machine it and it’s non-conductive, there are many other options you could try.

Using no special tools other than a collet block (like this one) all the angled holes and slots were made with ease, with the help of a specially 3D-printed mount for the vise. A nice, simple approach, we think!

[Andy] tested the repeatability of the probe, mounted over his CNC-converted Holbrook lathe, reporting a value of 1 um, which seems rather good. Centering of the probe tip within the probe body was off a bit, as you’d expect for something made practically by hand, but that is less of a problem as it would seem, as it results in a fixed offset that can be compensated for in software. Perhaps the next version will have some adjustability to dial that out manually?

The whole assembly is formed from two plastic parts, a handful of ground-finished hardened steel pins, and a big spring. The only part remotely special is an off-the-shelf probe tip. During the electrical hookup, you may notice the use of a self-fluxing verowire pen, which was something this scribe didn’t know existed and has already placed an order for!

The reference 3D model for the design is shared from [Andy]’s Autodesk Drive for your viewing pleasure.

Of course, this isn’t the first DIY touch probe we’ve seen, here’s one for example, and over on Hackaday.IO, here’s an attempt to make one using a piezoelectric transducer.

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USB Power Has Never Been Easier

January 5, 2022 by Brian McEvoy 48 Comments

USB cables inevitably fail and sometimes one end is reincarnated to power our solderless breadboards. Of course, if the cable broke once, it is waiting to crap out again. Too many have flimsy conductors that cannot withstand any torque and buckle when you push them into a socket. [PROSCH] has a superior answer that only takes a couple of minutes to print and up-cycles a pair of wires with DuPont connectors. The metal tips become the leads and the plastic sheathing aligns with the rim.

The model prints with a clear plus sign on the positive terminal, so you don’t have to worry about sending the wrong polarity, and it shouldn’t be difficult to add your own features, like a hoop for pulling it out, or an indicator LED and resistor. We’d like to see one with a tiny fuse holder.

If you want your breadboard to have old-school features, like a base and embedded power supply, we can point you in the right direction. If you are looking to up your prototyping game to make presentation-worthy pieces, we have a host of ideas.

3D Printering: One Bed Level To Rule Them All

January 5, 2022 by Al Williams 23 Comments

In an ideal world, your FDM 3D printer’s bed would be perfectly parallel with the print head’s plane of movement. We usually say that means the bed is “level”, but really it doesn’t matter if it is level in the traditional sense, as long as the head and the bed are the same distance apart at every point. Of course, in practice nothing is perfect.

The second best situation is when the bed is perfectly flat, but tilted relative to the print head. Even though this isn’t ideal, software can move the print head up and down in a linear fashion to compensate for the tilt. Things are significantly worse if the bed isn’t itself flat, and has irregular bumps up and down all over.

To combat that, some printer firmware supports probing the bed to determine its shape, and adjusts the print head up and down as it travels across the map. Of course, you can’t probe the bed at every possible point, so the printer will have to interpolate between the measured reference points. Marlin’s bilinear bed leveling is an example.

But if you have enough flash space and you use Marlin, you may want to try unified bed leveling (UBL). This is like bilinear leveling on steroids. Unfortunately, the documentation for this mode is not as plain as you might like. Everything is out there, but it is hard to get started and information is scattered around a few pages and videos. Let’s fix that.

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A PoE adapter's RJ45 jack added inside an Acer laptop

Laptop Empty Space Filled With RS485 And PoE

January 5, 2022 by Arya Voronova 6 Comments

Out of all the laptop upgrade options typically available, you wouldn’t expect this specific one. [controlmypad] decided to take a part of his RS485 device programming workflow and put it inside of a spare laptop he picked up for cheap. Typically, he’d occupy some desk space and lay out an unwieldy combination of a USB-RS485 dongle, a PoE power injector, a PSU for that injector, and a few cables to join it all – being extra weight in the tool bag, cluttering the workspace when laid out, and the RS485 adapter slowly wearing out the USB ports during the work-related motions. No reason that all of this couldn’t be packed inside a laptop, however.

What helps a lot is that, in many modern cheap laptops, the motherboard is fairly small, and the DVD drive plastic placeholder can be omitted without second thought. Cutting off the plastic molding from both of the adapters turns them into a nicely reusable circuit board and a small PoE module, respectively. After laborious yet careful cutting of the laptop case with a hobby knife, the PoE injector fits right in and, essentially, adds an extra RJ45 port to the laptop. From where the Hackaday.io write-up left off, it doesn’t seem like this mod got fully completed, but most of the important details are there for us to learn from. What got left out is connecting it to an internal USB port (should help that the motherboard’s schematics are available online), as well as creating 12V-24V from the laptop’s power rails. At this point, however, this mod is a big step forward usability-wise, even if it still requires an external PSU.

Laptop internal upgrade projects are rare but cherished – it’s a combination of “daring”, “inquisitive” and “meticulous” that results in people successfully hacking on a thing they certainly were not meant to hack, and have that thing serve their needs better. Apart from all the EEE PC upgrade options that set the bar for a generation of laptop modders, there’s a myriad of unconventional laptop modification vectors – you could do a thorough from-scratch Type-C charging port conversion, replace your webcam with an FSF-endorsed open firmware WiFi dongle, build in a “12-axis” sensor for auto-orientation and data-logging, or invent a remote self-destruct mechanism for your laptop. Those are, indeed, quite a few things you won’t typically find in the list of available options while customizing your laptop at the manufacturer website.

Does This Lead Make My Car Look Fat?

January 5, 2022 by Lewin Day 64 Comments

When looking at the performance of a vehicle, weight is one of the most important factors in the equation. Heavier vehicles take more energy to accelerate and are harder to stop. They’re also more difficult to control through the corners. Overall, anything that makes a vehicle heavier typically comes with a load of drawbacks to both performance and efficiency. You want your racecar as light as possible.

However, now and then, automakers have found reason to intentionally add large weights to vehicles. We’ll look at a couple of key examples, and discuss why this strange design decision can sometimes be just what the engineers ordered.

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Dice Rolls From The Beginning Of Time

January 5, 2022 by Bryan Cockfield 30 Comments

Generating random numbers might seem like a trivial task, that is until the numbers need to be truly random for cryptography or security reasons. When that’s the case, it turns out that these numbers are really “pseudo-random” and follow a predictable pattern. Devices that can produce truly random numbers often do it by sampling random events in the real world rather than relying on a computer to do it directly, like this machine which simulates a dice roll by looking at the cosmic microwave background radiation.

The cosmic microwave background radiation exists in the infrared at the farthest edges of the observable universe as a remnant of the big bang. It’s an excellent source of randomness, but tapping into it poses a bit of a challenge. For this build, [iSax] is using an old Soviet-era Geiger tube to detect the appropriate signal, and a Nixie tube to display the dice roll. After the device detects two particles from the Big Bang, the device measures the amount of time that passed between the detection of both particles and uses this number to calculate the dice roll.

While it takes a little bit longer to roll this dice than a traditional one since it has to wait to detect the right kind of particles, if you really need the randomness it can’t be beat. It certainly works as dice, but we can also see some use for generating truly random numbers for other applications as well. For some other sources of random inspiration be sure to check out our own [Voja Antonic]’s deep dive into truly random number generation.

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WiFi bird box with phone showing video of a rubber ducky

Building A WiFi-Enabled Bird Box On The Cheap

January 5, 2022 by Orlando Hoilett 12 Comments

[Jude] was looking for a fun DIY project for him and his son and thought that a bird box might be a good option. He wanted to equip the box with a WiFi camera so he could watch his little guests from his phone but didn’t find any suitable, inexpensive, commercially-available options. So with that, he built one himself.

He did, however, start with a generic bird box, which he bought online, and then modified with his particular features of interest. He wanted the project to be scalable so after-school programs and other kids clubs could easily implement his design within a classroom setting. He figured minimizing the woodwork would make the project easier for children.

He added a dowel to the generic bird box he bought online, but cautions that readers need to investigate if a dowel would attract invasive species in their area. He found a relatively inexpensive WiFi-enabled endoscope that he noted was far more affordable than the camera-equipped, commercially-available bird boxes he found earlier. He craftily used a plastic syringe as a waterproof spy hole that housed the endoscope, allowing him to easily slip the camera in and out of the bird box without disturbing its occupants. He noted that the 3 mL syringe had the perfect inner diameter to fit the endoscope rather snugly.

[Jude] doesn’t intend to have the endoscope active 24/7, so he needed a way to seal the access hole when the camera was not in use. His many years at Dyson taught him that implementing a removable, water-tight, rubber seal is not as easy as people may think. Fortunately, the rubber stopper at the tip of the syringe’s plunger was naturally a perfect removable seal and he could use it to plug the access hole when the endoscope was not in use.

The endoscope was mostly waterproof, except for the WiFi transmitter, so [Jude] needed to place that end of the device in a waterproof enclosure. He said these are often called “IP rated” enclosures and he figured these could come in handy for any number of outdoor electronics projects so we imagine this might come in handy for a lot of our readers as well.

Mother nature has certainly inspired many projects here at Hackaday and [Jude]’s bird box is no exception. Cool project!