SPATA: shaving seconds and saving brainpower whilst 3D-modeling

If you’ve spent some late nights CADing your next model for the 3D printer, you might find yourself asking for a third hand: one for the part to-be-modeled, one for the tool to take measurements, and one to punch the numbers into the computer. Alas, medical technology just isn’t there yet. Luckily, [Christian] took a skeptical look at that third hand and managed to design it out of the workflow entirely. He’s developed a proof-of-concept tweak on conventional calipers that saves him time switching between tools while 3D modeling.

His build [PDF] is fairly straightforward: a high-resolution digital servo rests inside the bevel protractor while a motorized potentiometer, accelerometer, and µOLED display form the calipers. With these two augmented devices, [Christian] can do much more than take measurements. First, both tools are bidirectional; not only can they feed measurement data into the computer with the push of at button, both tools can also resize themselves to a dimension in the CAD program, giving the user a physical sense of how large or small their dimensions are. The calipers’ integrated accelerometer also permits the user to perform CAD model orientation adjustments for faster CAD work.

How much more efficient will these two tools make you? [Christian] performs the same modeling task twice: once with conventional calipers and once with his tools. When modeling with his augmented device, he performs a mere 6 context switches, whereas conventional calipers ratchet that number up to 23.

In a later clip, [Christian] demonstrates a design workflow that combines small rotations to the model while the model is sculpted on a tablet. This scenario may operate best for the “if-it-looks-right-it-is-right” sculpting mindset that we’d adopt while modeling with a program like Blender.

Of course, [Christian’s] calipers are just a demonstration model for a proof-of-concept, and the accuracy of these homemade calipers has a few more digits of precision before they can rival their cousin on your workbench. (But why let that stop you from modifying the real thing?) Nevertheless, his augmented workflow brings an elegance to 3D modeling that has a “clockwork-like” resonance of the seasoned musician performing their piece.

[via the Tangible, Embedded, and Embodied Interaction Conference]

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Trinket EDC Contest: USB Calipers

[Lou]’s entry for the Trinket EDC Contest is a great addition to the ubiquitous digital calipers found on workbenches and eBay resellers the world over. It translates the value displayed on the calipers to a USB HID interface for logging all those tricky measurements at the push of a button.

Most of the digital calipers you’ll find at Harbor Freight or on eBay are pretty much the same. There are two pads on the caliper’s PCB that give any microcontroller the ability to read what is being measured. It’s done with a 24-bit encoding scheme, where each bit is a nearly-BCD measurement in units of 1/1000 of an inch or 1/100 of a millimeter. After decoding the value, [Lou]’s trinket sends a few numbers to a computer over a USB HID interface.

Simply sending a measurement to a computer over USB wasn’t enough for [Lou]. He added three buttons to the project for typing multiple characters. The first button just sends Enter to the computer, the second sends a comma, and the third sends “/2 (Enter)”, exactly what you need to input the radius of something when measuring the diameter.

This was a project for the Trinket EDC Contest that ended a few hours ago. Nobody knows who the winner is, but there are some pretty cool prizes up for grabs including the new Rigol scope, a Fluke 179, and a soldering station.

Supercharging your digital calipers


A dead battery in your digital calipers usually means a trip to the store for a new button cell. Not for [Trevor]. His hack substitutes a super capacitor, guaranteeing you’ll never need to rummage around for one of those pesky watch batteries again.

These calipers require only 20 seconds to reach a full charge that can last for a few days. Better still, [Trevor] designed a simple circuit with a voltage regulator at the end of the cord to allow charging via USB: just remember to flip the switch from “discharging” to “charging” mode. Although this is a fairly straightforward hack, its design is impressively tidy. The super capacitor fits perfectly at the end of the display and slides along with it, keeping it away from any important printed numbers. If these are the same calipers everyone seems to have these days, it looks like it may still fit in the provided case, too.

If you’re looking for more ways to beef up your calipers, try upgrading them with a Bluetooth module.

Giving digital calipers Bluetooth

[Fede]’s wife uses a pair of digital calipers to take measurements of fruits, leaves, and stems as part of her field research. Usually this means taking a measurement and writing it down in a log book. All things must be digitized, so [Fede] came up with a way to wirelessly log data off a pair of cheap Chinese calipers with a custom-made Bluetooth circuit.

Most of these cheap Chinese digital calipers already have a serial output, so [Fede] only needed to build a circuit to take the serial output and dump it in to an off-the-shelf Bluetooth module. He fabbed a custom circuit board for this, and after seeing the increased battery drain from the Bluetooth module, decided to add an external battery pack.

In addition to etching his own board for sending the serial output of the calipers to a Bluetooth module, [Fede] also put together a custom flex circuit to connect the two boards. It’s just a small bit of brass glued to a transparency sheet etched with ferric chloride, but the end result looks amazingly professional for something whipped up in a home lab.

Talking digital calipers make engineering more accessible


The team over at NerdKits recently put together a device aimed to help make the process of measuring things more accessible to those with disabilities. [Terry Garrett] is a Mechanical Engineering student, and as anyone who is in the field knows, it’s a discipline which requires taking tons of measurements. Since [Terry] cannot see he was often asking classmates to assist in measuring items during labs, but when he got a job at a nearby design studio, he knew he would have to find a way to take those measurements on his own.

Enter NerdKits.

[Humberto] wrote in to share how he and his team built a set of talking digital calipers to assist [Terry] in his daily tasks. They based the design off a previous project they worked on, getting digital readout data from a set of calipers. The DRO information is fed into an ATmega382p, which pieces together pre-recorded sound bites to announce the size of the object being measured.

As you can see in the video below, the system looks to work very well, and [Terry] is quite pleased with his new talking tool. We love seeing these sorts of hacks, because they truly make a difference in people’s lives – excellent job!

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Digital caliper modding

This particular hack is actually used in a kit design, but it’s still pretty sweet. This is a digital read out unit that’s a kit sold by shumatech. I’ve even mentioned it in passing before. The design takes in the pulses from inexpensive chinese made digital scales/calipers, and allows one stop calibration and ouput of three axis’s of measurement. Using the interface and a usb enabled pic, and you could make your own usb digital calipers… (Hmm, I might have to make some.)