Air Rocket Launch Pad UI Entertains Eager Kids

September 26, 2015 by Rud Merriam 9 Comments

Last spring [Mike] built a foam rocket launchpad which was a hit with the kids in his neighborhood. But the launch system was merely a couple of buttons so the early enthusiasm quickly wore off. He went back to the drawing board to make improvements and really hit the jackpot!

The original launch system had one button for building up air pressure with a second big red button of doom for launching the rocket. The problem was a complete lack of user feedback; all the kids could do is guess how long they needed to hold the button to achieve the highest launch. This revision adds flashing LEDs to hold the attention of the wee ones but to also function as a gauge for the new pressure control system. The visually fascinating control board also includes a removable key to prevent accidental launches.

The particulars of this are as you’d expect: it’s a bunch of plumbing to manage the air pressure, an Arduino to control it all, and additional electronics in between to make them work together.

We’re especially impressed by the leap in features and quality from the first version to this one. It’s a testament to the power of quick proofs-of-concept before committing to a more involved build. Great work [Mike]!

We’ve seen rocket launchers for adults and some neat mission control panels but [Mike’s] kid friendly launch controller really is out of this world (sorry, couldn’t resist). You’ll find a video demo of this launcher after the break.

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Learn Flip Flops With (More) Simulation

September 24, 2015 by Al Williams 6 Comments

In the previous installment, we talked about why flip flops are such an important part of digital design. We also looked at some latch circuits. This time, I want to look at some actual flip flops–that is circuit elements that hold their state based on some clock signal.

Just like last time, I want to look at sequential building blocks in three different ways: at the abstraction level, at the gate level, and then using Verilog and two online tools that you can also use to simulate the circuits. Remember the SR latch? It takes two inputs, one to set the Q output and the other to reset it. This unassuming building block is at the heart of many other logic circuits.

A common enhancement to the SR latch is to include an enable signal. This precludes the output from changing when the enable signal is not asserted. The implementation is simple. You only need to put an additional gate on each input so that the output of the gate can’t assert unless the other input (the enable) is asserted. The schematic appears on the right.

In the case of this simulation (or the Verilog equivalent), the SR inputs become active high because of the inversion in the input NAND gates. If the enable input is low, nothing will change. If it is high, then asserted inputs on the S or R inputs will cause the latch to set or reset. Don’t set both high at the same time when the enable is high (or, go ahead–it is a simulation, so you can’t burn anything up).(Note: If you can’t see the entire circuit or you see nothing in the circuit simulator, try selecting Edit | Centre Circuit from the main menu.)

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This Project Will Be Stolen

September 24, 2015 by Brian Benchoff 30 Comments

What do you get when you take a flight case from Harbor Freight, fill it up with random electronics junk, and send it off to a stranger on the Internet? The travelling hacker box. It’s a project I’m putting together on hackaday.io to emulate a swap meet through the mail.

The idea is simple – take a box of random electronics junk, and send it off to a random person on hackaday.io. This person will take a few items out of the box, replace those items with something sitting on their workbench, and send it off to the next person. This is repeated until the box is stolen.

Has something like this been done before? Yes, yes it has. The Great Internet Migratory Box of Electronics Junk was a thing back in the ‘aughts, with Hackaday (via Eliot) receiving a box (code name: Rangoon) from [John Park], before sending it off to [Bre Pettis]. The box subsequently disappeared. There were many migratory boxes of electronics junk, but most didn’t travel very far. Already the Travelling Hacker Box has 2,525 miles on its odometer, and plans are in the works for travelling 25,000 miles – the circumference of the Earth – before heading out of the United States.

If you’re wondering what’s in the box, here’s a mostly complete inventory. With the exception of a few items from the swag bag from the Open Hardware Summit last weekend, it’s mostly random electronics stuff I’ve had sitting around on my workbench and desk. The first recipient grabbed a few dev boards and replaced them with a Teensy LC and enough tubes to make a small amplifier.

The current plan for the Travelling Hacker Box is to bounce across the United States for the circumference of the Earth until departing for more exotic lands. There are people queued up to receive the box from across the world, and the box will eventually be hitting Europe, India, Africa, Asia, and Australia. Everyone is welcome to participate as it is passed from hacker to hacker as a migratory box of electronic toys.

Learn Flip Flops With Simulation

September 23, 2015 by Al Williams 19 Comments

Digital design with combinatorial gates like AND, OR, and NOT gates is relatively straightforward. In particular, when you use these gates to form combinatorial logic, the outputs only depend on the inputs. The previous state of the outputs isn’t important in combinatorial logic. While this is simple, it also prevents you from building things like state machines, counters, and even CPUs.

Circuits that use their own outputs as inputs are known as sequential circuits. It is true that at the fundamental level, sequential circuits use conventional logic gates. However, you usually won’t deal with them as gates, but will deal with abstractions like latches, flip flops, and even higher level constructs. Learning about these higher level constructs will allow you to make more advanced digital designs that are robust. In fact, if you are using an FPGA, building blocks like flip flops are essential since a large portion of the chip will be made up of some kind of flip flop.

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Omaha Mini Maker Faire: Recycle All The Things

September 21, 2015 by Kristina Panos 13 Comments

A young maker named [Allie] drew a lot of attention at the 2nd annual Omaha Mini Maker Faire. Her booth was full of the various creations she has designed and built herself throughout the course of her short life. The biggest draw was her green design dollhouse, which focuses on environmentally friendly living. With the exception of the LEDs lighting the interior, some tape, and the requisite bit of hot glue, the entire structure and its contents were made from recycled materials.

The cardboard structure features a kitchen, living room, bedroom, bathroom, and attic. Every piece of furniture and all the decorations are made from salvaged materials and packaging. One side of the roof holds a Snap Circuits board with a solar panel that powers some blue LEDs on the bedroom wall. [Allie] poured water down the other side of the roof to demonstrate the rain water collection system. The house’s rain barrel was made from a grated parmesan cheese container, which is perfectly designed for the airline tubing running into it from the recycled plastic guttering.

One of [Allie]’s other projects is a disagreeable owl fashioned from cardboard and a salvaged canister. Hidden away beneath the owl’s platform lies a simple gear system attached to a key on the front. Turning the key causes the owl’s head to swivel back and forth. We tried to make it spin all the way around, but the full range of motion is about 270 degrees. She also brought Mountain Dew, a hummingbird model made from a spark plug and other metal bits and bobs, including a pair of soda can wings.

In addition to her crafty skills, [Allie] is one well-spoken tween. She was more than happy to discuss her creations in detail to anyone who would listen, which included at least two local journalists and this impressed reporter. We learned through a bit of light research that a robot [Allie] built a few years ago inspired a British toy company to produce a new doll, the Robot Girl Lottie. She’s an inspiration to makers of all ages.

Ctrl-X, Ctrl-V For DNA

September 20, 2015 by Dan Maloney 23 Comments

Once upon a time, the aspiring nerdling’s gift of choice was the Gilbert chemistry set. Its tiny vials of reagents, rack of test tubes, and instruction book promised endless intellectual stimulation and the possibility of stink bombs on demand. Now a new genetic engineering lab-in-a-box Kickstarter, with all the tools and materials needed to create your own transgenic organisms, may help the young biohacker’s dreams come true.

The Kickstarter has been wildly successful. The initial goal was $1200AUD was met in a day, and currently stands at almost $6200AUD. Despite that success, color me skeptical on this one. Having done way more than my fair share of gene splicing, there seem to be a few critical gaps in this kit. For example, the list of materials for the full kit includes BL21 competent E. coli as the host strain. Those cells are designed to become porous to extracellular DNA when treated with calcium chloride and provided with a heat shock of 42°C. At a minimum I’d think they’d include a thermometer so you can control the heat shock process. Plenty of other steps also need fairly precise incubations, like the digestion and ligation steps needed to get your gene into the host. And exactly what technique you’d be using to harvest DNA from the animal, plant or fungal cells is unclear; the fact that most of the techniques for doing so require special techniques leads me to believe there’s a lot less here than meets the eye.

To be fair, I’ve been off the lab bench for the better part of two decades, and the state of the art has no doubt advanced in that time. There could very well be techniques I’m not familiar with that make the various steps needed to transform a bacterial culture with foreign DNA trivial. It could also be the case that the techniques I used in the lab were optimized for yield and for precise data, while the GlowGene kit provides the materials to get a “good enough” result. I hope so, because a kit like this could really expand the horizons of hackerdom and start getting the biohacking movement going.

[Thanks, Michael!]

Organize That Messy Prototype

September 20, 2015 by Rud Merriam 35 Comments

You’re working away busily at your project. A pcb here cabled to a breadboard in the middle, and over there some motors and other devices. It should work but it doesn’t. Time to hook-up the multimeter but the test point is on the other side. As things are moved around to reach the point, the magic smoke escapes from a critical component. Should have put those pliers away.

Workbenches are always messy. [Ryan Clark] may have an idea that can help. His Jigmod system — currently running a kickstarter campaign — uses ~~an acrylic~~ a polycarbonate sheet with a grid of mounting holes to keep prototyping hardware in place. If you need to move the prototype around there is no strain on the wiring and no way to set a circuit down on that pair of pliers. The positioning of everything is your decision.

[Ryan] is also providing breakout type boards for connectors like USB and Ethernet, switches, battery holders, and other typical components. This is one place where the system really shines. A lot of these interface connectors tend to be breadboard-unfriendly and the terminal blocks these modules offer solves those issues. When you need to demonstrate your project it’s easy to transport since everything is attached to the plate. No more disconnecting cables, especially jumper wires, and hoping you get them all hooked back the right way at the destination.

With so many dev boards out there we really enjoy seeing jigs that can hold them along with a breadboard. This Stickvise-inspired 3D printed jig sticks out in our minds as a favorite. Do you have your own system of organizing your prototype builds? We’d love to hear about it in the comments!