Friday Hack Chat: Trusting The Autorouter

February 21, 2018 by Brian Benchoff 41 Comments

Ah, the autorouter. Inside every PCB design tool, there’s a function called the ‘autorouter’. This function, when used correctly, is able to automagically lay traces between pads, producing a perfect board in under a minute. The trouble is, no one uses it. We have been told not to trust the autorouters and we hear a lot of other dire warnings about it. The autorouter never works. The autorouter will put traces everywhere. The autorouter doesn’t consider floorplanning, and sometimes you’re going to get traces that go right through the edge of your board. Is avoiding the autorouter sound advice?

For this week’s Hack Chat, we’re talking about trusting the autorouter. The autorouter is just a tool, and like any tool, it will do exactly what you tell it. The problem, therefore, is being smart enough to use the autorouter.

Our guest for this week’s Hack Chat is Ben Jordan, Director of Community Tools and Content at Altium. Ben is a Computer Systems engineer, with 25 years experience in board-level hardware and embedded systems design. He picked up a soldering iron at 8, and wrote some assembly at 12. He’s also an expert at using an autorouter successfully.

In this Hack Chat, we’re going to talk to Ben about Altium, Circuit Maker, and how to get the best performance out of an autorouter. How do you set the autorouter up? How do you test your settings? What, actually, is the technology and math that goes into an autorouter? What is the best way to design a multilayer board? How do you do multiboard designs? And what’s the deal with mixed signals?

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This Hack Chat is going down Friday, February 23rd at noon, Pacific time. Want to know what time this is happening in your neck of the woods? Here, look at the neat time zone converter thingy.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

3D Printed Skateboard Mount For Bikes

February 21, 2018 by Adam Fabio 16 Comments

[Matt Obal] had a problem. The local skatepark was too far to skateboard, but close enough to bike. Carrying a skateboard on a bicycle is a rather awkward (and unsafe) maneuver. [Matt’s] answer to the problem is Truck Stop, a bicycle mounted skateboard carrier he developed and is manufacturing himself.

[Matt’s] work on Truck Stop began about a year ago, with his purchase of a 3D printer. He designed a seat back mounted device that secures the skateboard by wedging between the truck and the board itself. The design is printed in PLA and is hollow. Truck Stop’s strength comes from being filled with resin and fiberglass cloth.

If you’ve worked with resin, you probably know that some formulas get hot while they harden. This caused a few melted prints until [Matt] figured out that a dunk in cold water at the right time would allow the resin to complete it’s hardening process while keeping the heat below the melting temperature of PLA. He’s since switched to a different resin formula that generates less heat.

[Matt] is selling the Truck Stop at his website, and spent quite a bit of time working on a silicon mold so he could cast as many mounts as he wanted. The problem was fiberglass poking through the final cast part. In the end, he decided to stick with the resin filled PLA of his prototypes.

The King Of Machine Tools

February 21, 2018 by Quinn Dunki 68 Comments

The lathe is known as the King of Machine Tools for a reason. There are very few things that you can’t make with one. In fact, people love to utter the old saw that the lathe is the only machine tool that can make itself. While catchy, I think that’s a bit disingenuous. It’s more accurate to say that there are parts in all machine tools that (arguably) only a lathe can make. In that sense, the lathe is the most “fundamental” machine tool. Before you harbor dreams of self-replication, however, know that most of an early lathe would be made by hand scraping the required flat surfaces. So no, a lathe can’t make itself really, but a lathe and a skilled craftsperson with a hand-scraper sure can. In fact, if you’ve read the The Metal Lathe by David J. Gingery, you know that a lathe is instrumental in building itself while you’re still working on it.

We’re taking trip through the machining world with this series of articles. In the previous article we went over the history of machine tools. Let’s cut to the modern chase now and help some interested folks get into the world of hobby machining, shall we? As we saw last time, the first machine tools were lathes, and that’s also where you should start.

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Learning The 555 From The Inside

February 21, 2018 by Steven Dufresne 6 Comments

One way to understand how the 555 timer works and how to use it is by learning what the pins mean and what to connect to them. A far more enjoyable, and arguably a more useful way to learn is by looking at what’s going on inside during each of its modes of operation. [Dejan Nedelkovski] has put together just such a video where he walks through how the 555 timer IC works from the inside.

We especially like how he immediately removes the fear factor by first showing a schematic with all the individual components but then grouping them into what they make up: two comparators, a voltage divider, a flip-flop, a discharge transistor, and an output stage. Having lifted the internals to a higher level, he then walks through examples, with external components attached, for each of the three operating modes: bistable, monostable and astable. If you’re already familiar with the 555 then you’ll enjoy the trip down memory lane. If you’re not familiar with it, then you soon will be. Check out his video below.

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An Especially Tiny And Perfectly Formed FM Bug

February 21, 2018 by Jenny List 17 Comments

It used to be something of an electronic rite of passage, the construction of an FM bug. Many of us will have taken a single RF transistor and a tiny coil of stiff wire, and with the help of a few passive components made an oscillator somewhere in the FM broadcast band. Connect up a microphone and you were a broadcaster, a prankster, and probably set upon a course towards a life in electronics. Back in the day such a bug might have been made from components robbed from a piece of scrap consumer gear such as a TV or VCR, and perhaps constructed spider-web style on a bit of tinplate. It wouldn’t have been stable and it certainly wouldn’t have been legal in many countries but the sense of achievement was huge.

As you might expect with a few decades of technological advancement, the science of FM bugs has moved with the times. Though you can still buy the single transistor bugs as kits there is a whole range of fancy chips designed for MP3 players that provide stable miniature transmitters with useful features such as stereo encoders. That’s not to say there isn’t scope for an updated simple bug too though, and here [James] delivers the goods with his tiny FM transmitter.

Gone is the transistor, and in its place is a MAX2606 voltage-controlled oscillator. The on-chip varicap and buffer provided by this device alleviate some of the stability issues suffered by the transistor circuits, and to improve performance further he’s added an AP2210 low-dropout regulator to catch any power-related drift. If it were ours we’d put in some kind of output network to use both sides of the differential output, but his single-ended solution at least offers simplicity. The whole is put on a board so tiny as to be dwarfed by a CR2032 cell, and we can see that a bug that size could provide hours of fun.

This may be a small and simple project, but it has found its way here for being an extremely well-executed one. It’s by no means the first FM bug we’ve shown you here, just a few are this one using scavenged SMD cellphone parts, or this more traditional circuit built on a piece of stripboard.

DIY Peristaltic Pump Keeps The Booze Flowing

February 20, 2018 by Kristina Panos 30 Comments

A few months ago we showed you a bar bot built by [GreatScott] that uses peristaltic pumps to food-safely move the various spirits and mixers around behind the curtain. The bar bot uses three of them, and at $30 each for pumps with decent flow rate, they added a lot to the parts bill. These pumps are pretty much the ideal choice for a bar bot, so what do you do? [GreatScott] decided to see if it was worth it to make them instead.

Peristaltic pumps are simple devices that pump liquids without touching them. A motor turns a set of rollers that push a flexible tube against a wall. As the motor turns, the rollers move liquid through the tube by squeezing it flat from the outside in turns. Typically, the more you pay for an off-the-shelf peristaltic, the higher the flow rate.

[GreatScott] figured it was cheaper to buy the motor and the control circuitry. He chose a NEMA-17 for their reputation and ubiquity and a DRV8825 controller to go with it. The pump is driven by an Arduino Nano and a pot controls the RPM. After trying to design the mechanical assembly from scratch, he found [Ralf]’s pump model on Thingiverse and modified it to fit a NEMA-17.

The verdict? DIY all the way, assuming you can print the parts. [GreatScott] was trying to beat the purchased pumps’ flow rate of 100mL/minute and ended up with 200mL/minute from his DIY pump. Squeeze past the break for the build video and demonstration.

Is there a bar bot build on your list? No? Is it because you’re more of a single-malt scotch guy? Build a peristaltic pachyderm to pour your potion.

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Dungeons And Dragons TV Tabletop!

February 20, 2018 by James Hobson 26 Comments

With little more than pen, paper, dice, and imagination, a group of friends can transport themselves to another plane for shenanigans involving dungeons and/or dragons. An avid fan of D&D and a budding woodworker, Imgurian [CapnJackHarkness] decided to build gaming table with an inlaid TV for their inaugural project.

The tabletop is a 4’x4′ sheet of plywood, reinforced from underneath and cut out to accommodate a support box for the TV. Each leg ended up being four pieces of 1’x4′ wood, laminated together with a channel cut into one for the table’s power cable. An outer ledge has dice trays — if they’re even needed in today’s world — ready for all those nat 20s, cupholders because nobody likes crying over spilled drinks, and electrical outlets to keep devices charged. Foam squares cover the tabletop which can be easily removed and washed if needed — but more on that in a second. [CapnJackHarkness] painted the table as the wood rebuffed many attempts at staining, but they’re happy with how it turned out.