Bamboo Plant Becomes A Stylish Light Switch

If flipping a regular old light switch or pressing buttons isn’t an adequately pleasing way to use your appliances around the house, how about poking at the leaves of a plant to turn on your lamp? [Xkitz] has provided a thorough breakdown of how to turn any conductive object in your living space into a nifty capacitive touch switch that adds a bit of charm to such an everyday action.

Creating an electrostatic field around a conductive medium, the capacitive touch relay constantly monitors this field and will toggle when any minuscule change to the capacitance is detected. [Xkitz] uses a bamboo plant as his trigger. Gently touching any leaf will still act as an adequate trigger — as cool demonstration of how the electrostatic field works.

Continue reading “Bamboo Plant Becomes A Stylish Light Switch”

Kansas City Maker Faire: Pi-Plates

As soon as he spied the Jolly Wrencher on my shirt, [Jerry Wasinger] beckoned me toward his booth at Kansas City Maker Faire. Honestly, though, I was already drawn in. [Jerry] had set up some interactive displays that demonstrate the virtues of his Pi-Plates—Raspberry Pi expansion boards that follow the HAT spec and are compatible with all flavors of Pi without following the HAT spec. Why not? Because it doesn’t allow for stacking the boards.

[Jerry] has developed three types of Pi-Plates to date. There’s a relay controller with seven slots, a data acquisition and controller combo board, and a motor controller that can handle two steppers or up to four DC motors. The main image shows the data acquisition board controlling a fan and some lights while it gathers distance sensor data and takes the temperature of the Faire.

The best part about these boards is that you can stack them and use up to eight of any one type. For the motor controller, that’s 16 steppers or 32 DC motors. But wait, there’s more: you can still stack up to eight each of the other two kinds of boards and put them in any order you want. That means you could run all those motors and simultaneously control several voltages or gather a lot of data points with a single Pi.

The Pi-Plates are available from [Jerry]’s site, both singly and in kits that include an acrylic base plate, a proto plate, and all the hardware and standoffs needed to stack everything together.

Fail of the Week: Arachno∙fail∙ia

Going down the list (FCC, CE, UL, etc.) we can’t think of a regulating body that will test for this failure mode. Reportedly, a $1M irrigation system was taken down by a spider. And an itsy-bitsy spider at that.

This fail turned up as a quick image post over on /r/mildlyinteresting but I wasn’t the only electronics person attracted like a moth to a flame. Our friend [Sprite_TM] popped in to answer a question about conformal coating. Seems this board was sealed in a waterproof enclosure but was obviously not conformally coated.

fotw-spider-short-relay-diagram[Sprite_TM] also helped out with some armchair-engineering to guess at what happened. It’s not hard to tell that the footprint on the board looks like a set of mechanical relays all in a line. He looked up the most likely pinout for the relay.

We’ve superimposed that pinout on the board to help illustrate the failure. High voltage comes in on the pin shown with the red trace leading away from it. On either side of that pin are the connections for the low voltage coil which switches from normally closed (the pin in the upper right that is not connected to anything) to the normally open pin (which has the wide trace leading away from it).

So there sat the high voltage pin in between the coil pins when, along came a spider. It shorted the pins and presumably all the way back to the power supply for the low voltage rail. [Fugly_Turnip] (the OP) share some additional detail about the system and this failure; in addition to this card it fried the control module as well.

Another comment on the same thread shares a different story of two boards mounted next to each other with a bug shorting a 1/4″ air gap between two boards and causing similar carnage. Have you encountered Arachno-fail-ia of your own? Let us know below.

2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which celebrates failure as a learning tool. Help keep the fun rolling by writing about your own failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Punch Cards

Before the Commodore 64, the IBM PC, and even the Apple I, most computers took input data from a type of non-magnetic storage medium that is rarely used today: the punched card. These pieces of cardstock held programs, data, and pretty much everything used to run computers in the before-time. But with all of that paper floating around, how did a programmer or user keep up with everything? Enter the punch card sorter and [Ken Shirriff[‘s eloquent explanation of how these machines operate.

Card sorters work by reading information on the punched card and shuffling the cards into a series of stacks. As [Ken] explains, the cards can be run through the machine multiple times if they need to be sorted into more groups than the machine can manage during one run, using a radix sort algorithm.

The card reader that [Ken] examines in detail uses vacuum tubes and relays to handle the logical operation to handle memory and logic operations. This particular specimen is more than half a century old, rather robust, and a perfect piece for the Computer History Museum in Mountain View.

It’s always interesting to go back and examine (mostly) obsolete technology. There are often some things that get lost in the shuffle (so to speak). Even today, punched cards live on in the automation world, where it’s still an efficient way of programming various robots and other equipment. Another place that it lives on is in voting machines in jurisdictions where physical votes must be cast. Hanging chads, anyone?

Continue reading “Punch Cards”

Controlling Mains Power Rube Goldberg Style

[g3gg0] has some nice radio equipment including an AOR AR-5000 receiver and a HiQ SDR. They are so nice that it appears they lack an on/off switch. [g3gg0] grew tired of unplugging the things, and decided to nerdify his desk with a switch that would turn his setup on and off for him. He decided to accomplish this task by emulating the Scroll, Number and Caps Lock LEDs on his keyboard via a Digispark board. He uses the LEDs to issue commands to the Digispark allowing him to control a 5V relay, which sits between it and the AC.

Starting off with some USB keyboard emulation code on the Digispark, he tweaked it so he could use the Scroll Lock LED as sort of a Chip Select. Once this is pressed, he can use the Caps Lock and the Number Lock LED to issue commands to the Digispark.

It’s programmed to only stay on for a total of 5 hours in case he forgets to turn it off. Let us know what you think about this interesting approach.

DDR-ing a Simon Game with a Raspberry Pi

Since 1998 we’ve been privileged to partake in an arcade game known as Dance Dance Revolution, but before that, way back in the 70’s, was the Simon game. It’s essentially a memory game that asks the player to remember a series of lights and sounds. [Uberdam] decided to get the best of both worlds and mixed the two together creating this giant foot controlled Simon game. (English translation.)

The wood platform that serves as the base of the project was fitted with four capacitive sensors, each one representing a “color” on the Simon game. When a player stomps on a color, a capacitive sensor sends a signal to a relay which in turn notifies the Raspberry Pi brain of the input. The Pi also takes care of showing the player the sequence of colored squares that must be stepped on, and keeps track of a player’s progress on a projector.

This is a pretty good way of showing how a small, tiny computer like the Raspberry Pi can have applications in niche environments while also being a pretty fun game. We all remember Simon as being frustrating, and we can only imagine how jumping around on a wooden box would make it even more exciting. Now, who can build a robot that can beat this version of Simon?

Continue reading “DDR-ing a Simon Game with a Raspberry Pi”

Hackaday Prize Entry: Controlling Relays Over WiFi

It’s been less than a year since the ESP8266 WiFi Module was released. This is a chip whose original data sheets were only available in Chinese, could only be controlled through AT commands, and was (originally) only sold through Seeed Studio and other various Chinese retailers. It had one thing going for it: it was five dollars. For the price of a crappy sub, you can blink an LED from the Internet. Needless to say, the ESP8266 is now very popular.

There are a lot of ESP8266 projects in The Hackaday Prize this year, and [David]’s project is making great use of the relatively meager pinout of this module. He’s built an 8-channel relay controller with a WiFi interface to control industrial equipment. It’s a great project, but just of many ESP projects in the prize this year.

The ESP doesn’t have a huge number of pins, but there are enough for some serious work with the right hardware. He’s using the ESP-12 module to get the most pins, and using an SPI port expander to drive an octet of relays. It’s a simple board, but everything you need to control a bunch of relays over WiFi is right there: LEDs, reset buttons, and RS232 level conversion.

You can check out a pair of very satisfying videos of relays clicking below.


The 2015 Hackaday Prize is sponsored by:

Continue reading “Hackaday Prize Entry: Controlling Relays Over WiFi”