The Progressive Snapshot is a small device that plugs into the ODB-II port on your car, figures out how terrible of a driver you are, and sends that data to Progressive servers so a discount (or increase) can be applied to your car insurance policy. [Jared] wondered what was inside this little device, so he did a teardown. There’s an Atmel ARM in there along with a SIM card. Anyone else want to have a go at reverse engineering this thing from a few pictures?
[Alex]’s dad received a special gift for his company’s 50th anniversary – a Zippo Ziplight. Basically, its a flashlight stuffed into the metal Zippo lighter we all know and love. The problem is, it’s battery-powered, and Zippo doesn’t make them any more. It also uses AAAA batteries. Yes, four As. No problem, because you can take apart a 9V and get six of them.
‘Tis the season to decorate things, I guess, and here’s a Hackaday snowflake. That’s from [Benjamin Gray], someone who really knows his way around a laser cutter.
HHaviing trouble wiith a debounce ciircut? HHer’s a calculator for just thhat problem. Put iin the logiic hhiigh voltage level, the bounce tiime, and the fiinal voltage, and you get the capaciitor value and resiistor value.
A harmonograph is a device that puts a pen on a pendulum, drawing out complex curves that even a spirograph would find impressive. [Matt] wanted to make some harmonographs, but a CNC and a printing press got in the way. He’s actually making some interesting prints that would be difficult if not impossible to make with a traditional harmonograph – [Matt] can control the depth and width of the cut, making for some interesting patterns.
The Mooltipass, the Developed On Hackaday offline password keeper, has had an interesting crowdfunding campaign and now it’s completely funded. The person who tipped it over was [Shad Van Den Hul]. Go him. There’s still two days left in the campaign, so now’s the time if you want one.
This wooden box is a wireless pinball controller and tablet stand. The idea is to set it on a workbench to give you some of the thrill of standing and playing the real thing. [Jeff] has been rather addicted to playing a pinball app on Android lately, and started the journey because he needed a way to give his thumbs some relief.
An Arduino monitors buttons on either side of this wooden controller. [Jeff] is new to working with hardware (he’s a Linux Kernel developer by trade) and was immediately struck with button debouncing issues. Rather than handle this in software (we’ve got a super-messy thread on that issue with our favorite at the bottom) he chose a hardware solution by building an SR latch out of two NAND gates.
With the inputs sorted out he added a BlueSMiRF board to the project which allowed him to connect a Nexus 7 tablet via Bluetooth. At this point he ran into some problems getting the device to respond to his control as if it were an external keyboard. His stop-gap solution was to switch to a Galaxy Tab 10.1 which wasn’t throwing cryptic errors. Hopefully he’ll fix this in the next iteration which will also include adding a plunger to launch the pinball, a part which just arrived in the mail as he was writing up this success.
We’ve embedded his quick demo video after the break.
Continue reading “Wireless pinball controller for tablet gaming”
Last month we asked you to send in your debounce code. You didn’t disappoint and it’s time to share the code received. There were some guideline for sending in code so if you don’t see yours here, it probably didn’t follow the rules, sorry. We also tried to weed out code that using delay loops for debounce. These tend to be a poor way to handle inputs because they monopolize the processor.
We wanted to add upvote/downvote buttons to each set of code to give some idea of a group consensus on code quality but there’s no good system available for multiple up/down vote widgets on one wordpress page. This results in a huge code dump for any one person to go through. If you’ve got any ideas on how to better organize this let us know: firstname.lastname@example.org.
We make no guarantees that this code is safe to use, or that it even works. Test it carefully before using for important tasks.
Join us after the break for a whirlwind of code examples.
If you’ve ever designed an embedded system with at least one button you’ve had to deal with button debouncing. This is also know as contact bounce, a phenomenon where a button press can be registered as multiple button presses if not handled correctly. One way to take care of this is with a hardware filter built from a resistor-capacitor setup, or by using a couple of NAND gates. We find that [Jack Ganssle] put together the most comprehensive and approachable look at contact bounce which you should read through if you want to learn more.
We’re interested in software solutions for debouncing buttons. This seems to be one of the most common forum questions but it can be hard to find answers in the form of reliable code examples. Do you have debounce code that you depend on in every application? Are you willing to share it with the world? We’d like to gather as many examples as possible and publish them in one-post-to-rule-them-all.
Here’s some guidelines to follow:
- Please only include debounce code. Get rid of other unrelated functions/etc.
- You should send C code. If you want to also send an assembly code version that’s fine, but it must be supplementary to the C code.
- Please comment your code. This will help others understand and use it. You may be tempted to explain the code in your email but this info is best placed in the code comments
- Cite your sources. If you adapted this code from someone else’s please include a note about that in the code comments.
As an example we’ve included one of our favorite sets of debounce code after the break. Please note how it follows the guidelines listed above.
Continue reading “Open Call: send us your Debounce code”