3D Printers Get A Fuel Gauge: Adding A Filament Scale To OctoPrint

August 10, 2018 by 17 Comments

It seems a simple enough concept: as a 3D printer consumes filament, the spool becomes lighter. If you weighed an empty spool, and subtracted that from the weight of the in-use spool, you’d know how much filament you had left. Despite being an easy way to get a “fuel gauge” on a desktop 3D printer, it isn’t something we often see on DIY machines, much less consumer hardware. But with this slick hack from [Victor Noordhoek] as inspiration, it might become a bit more common.

He’s designed a simple filament holder which mounts on top of an HX711 load cell, which is in turn connected to the Raspberry Pi running OctoPrint over SPI. If you’re running OctoPrint on something like an old PC, you’ll need to use an intermediate device such as an Arduino to get it connected; though honestly you should probably just be using a Pi.

On the software side, [Victor] has written an OctoPrint plugin that adds a readout of current filament weight to the main display. He’s put a fair amount of polish into the plugin, going through the effort to add in a calibration routine and a field where you can enter in the weight of your empty spool so it can be automatically deducted from the HX711’s reading.

Hopefully a future version of the plugin will allow the user to enter in the density of their particular filament so it can calculate an estimate of the remaining length. The next logical step would be adding a check that will show the user a warning if they try to start a print that requires more filament than the sensor detects is currently loaded.

This is yet another excellent example of the incredible flexibility and customization offered by OctoPrint. If you’re looking for more reasons to make the switch, check out our guide on using OctoPrint to create impressive time lapse videos of your prints, or how you can control the printer from your mobile device.

A Display Made From Shoelaces

August 10, 2018 by 5 Comments

In our time here at Hackaday, we have seen many display builds, but this one from [Brian Lough] has to be a first. He’s created a 7-segment display made from shoelaces, and it works rather well.

Before you imagine the fabric cords you’re used to with your trainers, it’s worth explaining that these aren’t shoelaces in the traditional sense, but transparent light pipe taken from commercially available light-up shoelaces. He’s created a 3D-printed frame with receptacles for each end of the light pipe sections he’s used as segments, and spaces for addressable LEDs on the rear. He makes no bones about his soldering job being less than perfect, but the result when hooked up to an Arduino is very impressive. A large 7-segment LED display that’s visible in the glare of his bench lighting and not just in subdued illumination. Future plans include replacing the messy wiring with stripboard sections for a better result.

This isn’t the first 7-segment display using a light pipe that we’ve seen here at Hackaday, a previous effort used a more novel substance. But perhaps this Nixie-inspired take on the same idea also deserves a mention.

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Op Amps Before Transistors: A 600V Vacuum Tube Monster

August 9, 2018 by 11 Comments

Op amps. Often the first thing that many learn about when beginning the journey into analog electronics, they’re used in countless ways in an overwhelmingly large array of circuits. When we think about op amps, images of DIPs and SOICs spring to mind, with an incredibly tiny price tag to boot. We take their abundance and convenience for granted nowadays, but they weren’t always so easy to come by.

[Mr Carlson] serves up another vintage offering, this time in the form of a tube op amp. The K2-W model he acquired enjoyed popularity when it was released as one of the first modular general purpose amplifiers, due to its ‘compact form’ and ‘low price’. It also came with large application manuals which helped it to gain users.

In order to power up the op amp and check its functionality, +300V and -300V supplies are needed. [Mr Carlson] is able to cobble something together, since it’s very apparent that he has an enviable stash of gear lying around. A 600V rail to rail supply is not something to be taken lightly, though it does give this particular model the ability to output 100V pk-pk without any distortion.

The op amp is set up as an inverting amplifier, and once powered on proves to work flawlessly. As always, the video is an entertaining watch, stuffed full of retro electronics trivia. We’re big fans of [Mr Carlson]’s work, and have previously written about his adventures with a colossal walk-in AM radio transmitter, as well as his restoration of a 1930s oscilloscope and subsequent transformer de-potting.

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High Tech Drone Scarecrows Can Make Airports Safer

August 9, 2018 by 8 Comments

If you pay attention to airplane news — or you watched the film Sully — you know planes have problems with birds. Sully was about US Airways flight 1549 which struck a flock of geese and ditched in the Hudson river.  Engineers at Caltech say that was the inspiration for them to develop a control algorithm that enables a single drone scarecrow to herd flocks of birds away from airports.

Airports have tried a lot of things to discourage birds ranging from trained falcons to manually-piloted drones. Apparently, herding birds is harder than you would think. If you fly the drone too far from a flock, it will ignore the threat. If you get too close, the flock will scatter making it both threaten a larger area and harder to control.

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Python Resurrects Dot Matrix Printing

August 9, 2018 by 54 Comments

These days a printer — especially one at home — is likely to spray ink out of nozzles. It is getting harder to find home laser printers, and earlier printer technologies such as dot matrix are almost gone from people’s homes even if you’ll still see a few printing multipart forms in some offices.

[Thomas Winningham] bought an old Commodore dot matrix printer in a fast food parking lot for $20. How hard could it be to get it working? How hard, indeed. Check out the video below to see the whole adventure. The principle behind the printer is simple enough. The head has one or two rows of pins each controlled by a solenoid. The head moves across the paper and your job — should you decide to accept it — is to make the pins push out at the right spot. An ink ribbon like a typewriter uses — oh yeah, more vanishing tech — leaves ink on the paper where it gets punched by the pin.

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First Look At DEF CON 26 Official Badge

August 9, 2018 by 25 Comments

To the delight of everyone, this year’s official DEF CON badge is an electronic badge chock full of entertainment. Of course there is blinky, the board is artistic, and everyone hopefully maybe gets one (it’s rumored 27,000+ were manufactured) if they don’t run out. But the badge contest at DEF CON is legendary — solve all the puzzles you are awarded the coveted black badge.

The creators of this badge are no strangers to the Hackaday community. Displayed proudly on the board and in the firmware, we discover that The Toymakers are the ones who have put it all on this line this year. Kudos to the dynamic hardware collective from Minnesota. There is no larger pressure cooker in the world of badges than this, and they pulled it off marvelously. Let’s take a look at all the goodies inside.

Most importantly, become a team member of the Hackaday.io DC26 badge solving project page to help discover all that’s involved in this badge. Okay, now let’s dive in!

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Big Power, Little Power, Tiny Power, Zap!

August 9, 2018 by 4 Comments

Our Hackaday Prize Challenges are evaluated by a panel of judges who examine every entry to see how they fare against judging criteria. With prize money at stake, it makes sense we want to make sure it is done right. But we also have our Hackaday Prize achievements, with less at stake leading to a more free-wheeling way to recognize projects that catch our eye. Most of the achievements center around fun topics that aren’t related to any particular challenge, but it’s a little different for the Infinite Improbability achievement. This achievement was unlocked by any project that impressed with their quest for power, leading to some overlap with the just-concluded Power Harvesting Challenge. In fact, when the twenty Power Harvesting winners were announced, we saw that fourteen of them had already unlocked the achievement.

Each of the Power Harvesting winners will get their own spotlight story. And since many of them have unlocked this achievement, now is the perfect time to take a quick tour through a few of the other entries that have also unlocked the Infinite Improbability achievement.

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