Month: December 2015

Hacking The Leapfrog TV To Play Doom

December 24, 2015 by 16 Comments

In a few hours, millions of fresh-faced children will be tearing open presents like the Leap TV, a Wii for the pre-school crowd that has a number of educational games. And, once they get bored with them, what could be more educational than fighting your way through a horde of demons to save the earth? Yup, [mick] has hacked the Leap TV console to play Doom. After some poking around he discovered that the Leap TV is built around a quad-core nxp4330q arm7-A processor, with 1GB of RAM and 16GB of flash memory, while the controller links to the main console using Bluetooth LE. That’s more than enough to run Doom on (in fact… too much), so he whipped out his handy compiler and got Doom and SDL running with only a few minor code changes.

This isn’t [Mick]s first such hack: he previously hacked the V-Tech InnoTab, a cheap tablet for kids, which persuaded the manufacturers to release the full source code for the tablet. Will Leapfrog follow suit? That remains to be seen, but in the meantime, [Mick]s work gives us some insight into the internals of this device.

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POV Globe Display Spins Up Full Color Tupac

December 24, 2015 by 11 Comments

Persistence of vision projects were once all the rage, judging by a quick review of the literature here on Hackaday. They’ve tapered off a bit lately, but this impressive full-color globe display might just kick-start some new POV projects.

Built as a final project for an EE course, [Evan] and [Kyle]’s project is more about the control electronics and programming than the mechanical end of the build. Still, spinning a 12″ ring of 1/4″ thick acrylic with a strip of APA102 LEDs glued to the edge takes some thoughtful engineering. While the build appears sturdy, [Evan] does admit to a bit of wobble under full steam, which was addressed by adding some weight to the rig. We wonder if mounting half the LEDs on each side of the ring to balance the forces wouldn’t have worked better. True, it would have complicated the coding for the display, but maybe that would have been good for extra points. In any case, the display turned out well and the quality of the images is great. And as an aside: how awesome is it that we live at a time when you can order a six-circuit slip-ring for a project like this for less than $20?

It’s the end of the semester and we love seeing the final projects that have just made it across the finish line. This globe is one, yesterday we saw a voice-controlled digital eye exam, and if you have or know of a final project, don’t forget send us the link!

If POV globes are your thing, be sure to set the Hackaday WABAC machine a few years and check out this Death Star design from 2012 or this globe from 2010.

23 Superconference Talks You Shouldn’t Miss

December 24, 2015 by 7 Comments

November marked our inaugural Hackaday Superconference, something we’ve been wanting to do for a very long time. Hackaday already has a massive and vibrant online community, but until now, we haven’t asked people to come together for a hardware conference that spans a full weekend. The Supercon is Hackaday incarnate, and hundreds of very cool people showed up for a few dozen talks, amazing workshops, and a lot more.

Over the past month, we’ve been putting together a compilation of everything that happened at the first Hackaday Superconference. This includes videos of all the talks, relevant asides, and posts for everything that happened over a two-day conference. Even if you couldn’t make it out to our first con, this great material that should be shared by all.

Below is a YouTube playlist of all the talks. If you’re looking for eight hours to kill over the holiday weekend, well, there you have it. After the break is the complete conference indexed by day and speaker, with links to the talk and accompanying Hackaday post.

We’d like to thank everyone who came out to the first Hackaday Supercon, with a huge shout-out to the speakers, workshop organizers, and volunteers. It couldn’t have happened without the full support of the Hackaday community. That’s good, because we’re going to be doing this again next year.

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Hackaday At 32C3 And Shmoocon

December 24, 2015 by 4 Comments

We are just a few days away from the 2015 Chaos Communications Congress in Hamburg Germany and we’re happy to say that a couple of the Hackaday crew will be on hand.
The annual event is one of the premier hacker conferences in the entire world. CCC-fairydustBoth [Voja Antonic] and [Nava Whiteford] will be attending this year’s 32C3, which runs from Sunday the 27th through Wednesday the 30th.

[Voja] will be pretty busy working a booth that will show off two of his projects. One is his Single-Chip Gaming System and the other is his DIY Book Scanner. If you do want to track him down, he dusted off his Twitter account, @Voja_Antonic, just for the event.

[Nava] will be less tied town, and looking for the best there is to see at the conference. If you want to connect with him, give his Twitter account a jingle: @new299.

2016 Shmoocon

schmoocon-bikerShmoocon is in the middle of January and boasts “Less Moose than Ever”. It’s notoriously hard to get a ticket for the annual hacker convention held in Washington, DC. We asked for three press passes and they were kind enough to provide one. We tried and failed to get tickets during the second public release, which sold out 900 passes in 7.58 seconds.

We’re Looking for One More Ticket!

We were able to purchase a single ticket second-hand, so along with the press pass we now have two. [Mike] and [Brian] are both planning to attend, but we’d like it if [Sophi] could be there as well. If you know of an extra ticket which we can buy at face value, please email mike at Hackaday with the details.

Will you be at Shmoocon? Want to meet up with [Brian], [Mike], and hopefully [Sophi], or know of an activity there we just shouldn’t miss? Ping us on Twitter (@szczys, @bbenchoff, @sophikravitz).

Also, how are our choices on con attendance so far? Leave a comment below and let us know what hacking events you think we just shouldn’t miss in the coming year.

You Can Learn A Lot From A Dummy (Load)

December 24, 2015 by 53 Comments

If you work on RF circuits–even if you aren’t a ham radio operator–you ought to have a dummy load. A dummy load is a non-radiative “antenna” with known impedance that you can use to test your RF circuit without radiating. For radio work, you usually just need a 50-ohm resistor that is non-inductive (at least at the frequencies you are interested in) and that can dissipate the amount of power you’ll expect it to handle (at least for a short time). [VO1PWF] wanted a dummy load and built his own.
CantennaThe Cantenna (not the Pringle’s kind; see right) was a famous dummy load design when Heathkit was in business. It was a single carbon rod immersed in a paint can full transformer oil (which we now know was full of dangerous PCBs; and we don’t mean printed circuit boards). [VO1PWF’s] design is a little more practical, using some resistors in parallel (20 1K resistors), a plastic pipe housing, and mineral oil to keep it all cool.

The reason for the parallel resistors is to maximize the power handling capability. The resistors are 3W units, so the dummy load–in theory–can handle 60 watts. Often, high power resistors are wire wound and thus have a good bit of parasitic inductance that makes the dummy load reactive (not a good thing since that makes the load impedance vary by frequency). They do make non-inductive wire wound resistors, but these aren’t truly non-inductive. The wire winds in two different directions, so the inductance tends to cancel out. We wouldn’t trust them to be a pure resistance in a high-power dummy load design.

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Nick Sayer: Making 10ⁿ Isn’t The Same As Building One

December 24, 2015 by 27 Comments

Building one of something is tremendously easy. If you’re making one of something, you can cover the insides with hot glue, keep everything held together with duct tape, and mess around with it enough that it mostly works most of the time. Building more than one of something is another matter entirely. This is the thought behind DFM, or Design For Manufacturing. [Nick Sayer] is an experienced seller on Tindie and he’s put together enough kits to learn the ins and outs, rights and wrongs of building not one, but an inventory of things. Check out this last talk of the 2015 Hackaday SuperConference, then join us below for a bit more on the subject.

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Beyond Control: Maths Of A Control System

December 24, 2015 by 28 Comments

Control systems are all around us, and understanding them is going to make you much better at hardware design. In the last article — Beyond Control: The Basics of Control Systems — we looked at an overview of what a control systems are in general with the example: “everything in between water and time is a control system”. We also observed control systems in nature, where I described my keen ability to fill a glass of water without catastrophic results. That discussion involved the basic concept of a block diagram (without maths) and we expanded that a bit to see what our satellite dish example would look like (still without maths).

I promised some big ugly maths in this article, and we’ll get to that in a bit, never you fear. First let’s have a look at how some basic elements: resistors, inductors, and capacitors are defined in the time domain. Don’t let these first few definitions turn you off. No matter how you feel about calculus, you don’t necessarily need to fully understand each equation. What’s more important is how the equations themselves combine to solve the circuit. Also important is that I will do everything possible to get out of doing difficult math. So stick with me through the article and you’ll learn that agony-saving trick for yourself!

A quick recap on transfer functions before we get going might be beneficial. A control system is used to define electromechanical behavior. For example: our satellite dish (from the previous article) at some point will need to be moved from one position to another position and as control engineers it is our job to determine just how this action will take place. I’m not talking about setting the mood for the big emotional robotic rotation, more like: not damaging the equipment or any people that might be nearby when moving the dish. For many reasons the dish would need to be moved with extreme care and in a very precise manner. The control system is the mathematical definition of that movement. Often the maths of the definition are nasty differential equations, (remember I’m avoiding any math that can be avoided, right?) so, instead of using differential equations to define the system, the transfer function will define the system with algebra, relating the output of the system to the input.

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