Here’s a project that you don’t want to bring into an airport, ship through the mail, or probably even remove from your home. [ProjectGeek] has built himself a simple kitchen timer masquerading as a bomb. The build is actually pretty simple, but the end result is something that would look at home in a Hollywood action flick.
The timer circuit is built from four simple components. An 8051 microcontroller board is used as the primary controller and timer. The code is available on GitHub. This board is attached to a another board containing four momentary push buttons. These are used to program the timer and to stop the buzzing. Another board containing four 7-segment displays is used to show the remaining time on the timer. A simple piezo buzzer is used to actually alert you when the timer has run out. All of these components are connected with colorful jumper wires.
The physical part of this build is made from easily available components. Old newspapers are rolled up to form the “explosive” sticks. These are then covered in plain brown paper ordinarily used to cover text books. The rolls are bundled together and fixed with electrical tape. The electronics can then be attached to the base with some hot glue or double-sided tape.
This is it. It’s time to step up and be a hardware hacker.
If you haven’t submitted your entry for The Hackaday Prize, get out that graph paper and mechanical pencil and start scribbling. The coming fortnight is your time to shine.
As of right now you have exactly fifteen days to tell us about your concept for an Open, Connected device. This doesn’t mean you have to finish the build, there’s time for that after the August 20th deadline. What you do need to do is describe your idea and explain how you plan to build a working prototype for the final deadline in early November.
I’ve appealed to your vanity — it’s hard to call yourself a hacker if you sit on the sidelines for this one! Now I’ll appeal to your want of recognition and the prizes that dreams are made of. Right now we haven’t quite crossed the 500 entry mark. When was the last time you had a chance as good as 1 in 500 for such a huge bag of booty?
Sure, it’s time to get the countdown clocks ready to ring in the new year, but why limit it to just one night? If you end up building a six-foot digital display you can count down trivial events; like the remaining seconds of freedom before you have to pimp yourself out in that drab cubicle.
This seven-segment display is homemade and boasts six full-sized digits and two smaller digits with each pair separated by colons. You have probably already guessed that the construction was greatly simplified by using LED strips rather than individual components. This is part of the reason for the size of the display. The strips can be cut, but only down to a minimum of 3 LEDs per segment. That explains the small digits, with their larger siblings doubled in size. But there is a benefit to this constraint, it means that current limiting is already taken care of for you.
The main assembly is a wooden frame surrounding two polycarbonate sheets. The LED strips are sandwiched between those sheets, with segment and digit driver buses exiting a one point on the side. The build doesn’t detail a driver for the display but it shouldn’t be hard to find a multiplexing example that will serve the purpose.
[John Graham-Cumming] was all set to start a new project based on the Raspberry Pi. Well, that was until shipment was delayed due to manufacturing issues. Not to fret, he transitioned over to a router board which displays the arrival countdown for mass transit bus service.
He based the build on a web page the Transport for London provided. You can load it up and see if your bus is running on time or not. There’s no published API, but by studying the source code from the site [John] was able to figure out how the JSON commands were formatted.
The next step is building a standalone device to pull the data and display it. The board seen above is from a Linksys WRT54GL router. This longtime favorite has a serial port header which can be driven from the Linux kernel. He wired up a jack on the router’s case, and uses an extension cable to get from it to the 7-segment displays mounted in a model of the bus. Since there’s four digits the display can tell you minutes until the arrival of two different buses.
[Thanks Pseudo Lobster]