digital caliper

Ask Hackaday: What Tools Do You Reach For First?

October 13, 2017 by 173 Comments

Let’s face it, in your workshop there are convenient tools, and there are quality tools, but so often they aren’t both. Think back to the tools you reach for first. Very often for me, speed and convenience win out. I don’t want to look too hard for that drill or saw, and want them to work as expected when I reach for them. At the same time, there are some tools that simply must be stored away, and can’t perch on my workbench forever or sit on a shelf.

It really is a balancing act sometimes. I don’t have a sure fire formula for when to break out the expensive tools, and what jobs are easy with the less expensive. I’ll lay out some of my most-often utilized tools in my arsenal, then I want to hear from you on your own faves.

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Making an Inexpensive DRO

May 26, 2017 by 19 Comments

[Andrew] wanted a digital readout (DRO) for his mini lathe and mini mill, but found that buying even one DRO cost as much as either of his machines. The solution? You guessed it, he built his own for cheap, using inexpensive digital calipers purchased off eBay.

The DRO he created features a touch screen with a menu system running on an LPCXpresso, while smaller OLED screens serve as labels for the 7-segment displays to the right. The DRO switches back and forth between the lathe and mill, and while the software isn’t done, [Andrew] hopes to be able to transfer measurements from one machine to the other.

In a very sweet touch, [Andrew] hacked cheap digital calipers to provide measurements for each axis, where they provide a resolution of 0.01mm. There are six daughter boards, one for each caliper, and each has a PIC that converts from serial to I2C, freeing the main firmware from dealing with six separate data streams.

The DRO doesn’t have a case, [Andrew] has it positioned out of chip-range from either machine.

A previous DRO we featured in 2012 used an Android tablet as its display.

Giving digital calipers Bluetooth

June 20, 2013 by 28 Comments

[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.

Reverse engineering salvaged part footprints

February 1, 2013 by 35 Comments

reverse-engineering-component-footprints

So you just pulled a fancy component off of a board from some broken electronics and you want to use it in your own project. What if the data sheet you found for it doesn’t include measurements for the footprint? Sure, you could pull out your digital calipers, but look at the measurements in the image above. How the heck are you supposed to accurately measure that? [Steve] found an easy answer for this problem. He uses microscope software to process an image of the board.

One common task when working with a microscope is measuring the items which are being viewed under magnification. [Steve] harnessed the power of a piece of free software called MiCam. One of its features is the ability to select an area of the photograph so serve as the measuring stick. To get the labels seen in the image above he selected the left and right edges of the board as the legend. He used his digital calipers to get a precise measurement of this area, then let the software automatically calculate the rest of the distances which he selected with his cursor.

MiCam is written for Windows machines. If you know of Linux or OSX alternatives please let us know in the comments.

Hold, fast, and max features on a digital caliper

January 12, 2011 by 63 Comments

While adding an RJ-11 connector to his digital calipers [BadWolf] slipped, shorting out a pin and accidentally discovered new features. He intended to add a port for reading measurement data electronically, but after the slip-up an ‘H’ appeared on the LCD screen and the measurement was frozen at the same number. At first it seemed like he may have killed the device, but this is actually a hold function. A little bit more playing around and he discovered that a combination of button presses can also enable a fast function which speeds up the rate at which the display changes its reading. There is even a max function that only updates the display if the reading is higher than any previously displayed measurement. These are nice features which he uses by connecting a momentary push switch between two of the output pins, details we gleaned from the annotated video after the break. He doesn’t say which pins work for him, but we’d bet one of them is the ground pin on the port, and the other is one of the two data pins. Do some investigating with your own calipers and let us know what you find in the comments.

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