PIC-based Ham Radio Autotuner

April 7, 2011 by Mike Nathan 6 Comments

cw_autotuner

A few years back, [Floyd, K8AC] built a high frequency autotuner as an addition to his Ham radio setup. Based off a design he saw in QST magazine back in the early ’90s, he has been using the tuner almost daily for the last few years, on both the 3.5 MHz and 7 MHz bands.

Built into the wall in his radio room, it is a pretty impressive sight. His “L” circuit is controlled by a pair of mechanically coupled inductors which are driven in concert by a pair of two-way motors. The positioning of the C and L components are monitored by a PIC controller which stores the tuning data for up to 30 predefined frequencies. A couple of button presses on his controller’s front end sends the tuner into action, dialing in his unit’s inductors and capacitor to their proper settings. The PIC monitors the tuner’s progress, informing him when the proper frequency has been tuned in, or if the frequency can not be set, indicating issues with the equipment.

His setup has undergone several revisions over the years, with the most recent iteration being the most automated of the bunch. Check out his site for plenty more details, or keep an ear out for [K8AC] on 40 or 80 meters.

[Thanks, Rich V]

Reverse Engineering LED Vodka Bottle Displays

April 6, 2011 by Mike Nathan 10 Comments

wireless_led_marquee

When [Tyler] heard about the LED matrix display that Medea Vodka was building into their bottles, he immediately wanted to get his hands on one. Who could blame him? Someone had finally combined two things we love dearly: booze and LEDs.

He struggled to find a bottle at any of his local stores for the longest time, but was absolutely stoked when he finally came across one of their reps promoting the brand while he was out shopping.

Once he got home, he pulled the display off the bottle and began poking around to see what made it tick. The display is made from a flexible PCB, and attached to the bottle with some clear elastic film. It is powered by two CR2032 batteries and controlled by a PIC16F chip, which pulls stored messages from a small Atmel EEPROM.

Once he figured out how to control the LED matrix, he uploaded his own fonts and added a LINX wireless module to remotely send messages to the board. He mounted it in a wooden frame and now uses it as a simple marquee display.

If you have one of these displays hanging around your house, be sure to swing by his site for schematics of his wireless interface board as well as the code he uses to drive the marquee. You can check out a video of the display in action there as well.

Gun Turret Built Into A Cake Box

April 3, 2011 by Mike Szczys 17 Comments

Couch potatoes have a new line of defense thanks to this remote-controlled turret. The gun itself is a hacked down airsoft model. The mount started with a servo motor in the center of a plastic cake box. A thin strip of plywood was added, along with a couple of sliding furniture feet to stabilize the platform as it rotates. A second servo mounts to that platform, which allows the trajectory of the projectile to be adjusted up or down. A PIC 18F4520 controls both of the motors, as well as the firing of the airsoft module, all while listening for commands from an IR receiver. Just adjust the firmware to match an unused device on your universal remote and the power to annoy your roommates will be at the tips of your fingers.

You can see an overview of the build process, as well as a demonstration of the final project in the video after the break. The page linked at the top has a very detailed build log but some of the ‘next’ buttons on that page don’t work for us. Luckily you’ll see a table of contents in the right column which lets you navigate around these bad links.

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Super Pong Table Doubles The Fun

March 29, 2011 by Mike Nathan 8 Comments

super_pong

While Pong has traditionally been a game played between two individuals, Instructables user [Brad] has put together a variation that doubles the fun. His Pong coffee table has the ability to support up to four users at once, and makes for quite the living room centerpiece.

The table is made from sheets of MDF and incorporates a grid of 900 LEDs, all controlled by a PIC18 micro controller. The MCU is installed on a control board he designed, along with the other additional bits required to drive the LED array. A set of old Atari paddle controllers were disassembled and installed around the table, making this a true retro Pong experience.

As you can see in the video, the action is pretty frantic. It’s hard to tell who is winning until the game is over, but [Brad] says that a scoreboard will come in a future revision.

4-way Pong is a really cool idea! ~~, but it looks like there are no open source schematics or code for the control board. We’re hoping someone sees this project and puts together a version for all to use, free of charge.~~

We were mistaken about the status of this project in relation to whether or not it was open source. [Brad] wrote to us letting us know that his code was not originally included with the Instructable as a result of a late night omission. As always, his projects are open source, and you can now download all of the source code and schematics at the page linked above (and in the first step of the Instructable, no less). Mea culpas all around, thanks for the update, [Brad]!

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POV Business Card Is Guaranteed To Get You Noticed

March 21, 2011 by Mike Nathan 17 Comments

Some say that handing out business cards is an antiquated practice due to the ubiquity of smart phones which can be used to trade or record contact information in mere moments. Instructables user [sponges] however, doesn’t agree and is pushing a “business card renaissance” of sorts with his POV business card.

Hand-built in his basement, the cards feature a handful of SMD LEDs that display his name, followed by his phone number when waved back and forth. Constructed to be nearly the same size as a standard business card, his verison uses a PIC to manage the display as well as a tilt sensor to monitor the card’s motion. His walkthrough is quite thorough, and includes tutorials for each of the steps required to build the card. He discusses constructing your own etching tank, converting a laminator for PCB transfer purposes, building a solder reflow oven controller, as well as hacking an aquarium pump for use as a vacuum-powered pick and place.

The end result is a sharp looking business card that ensures you won’t forget meeting him. Keep reading to see a video of the card in action.

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Building A Home Automation Mesh Network

March 19, 2011 by Mike Szczys 12 Comments

[Ian Harris] designed a bunch of home automation for his parents using X10 hardware. He was a bit disappointed by the failure rate of the modules and the overall performance of the system so he set out to replace it with his own hardware. Lucky for use he’s documented the journey in a four-part series about mesh networks.

The hardware seen above is his test rig. He’s using a couple of Sparkfun breakout boards to develop for nrf2401a RF transceiver chips. These could be used as slave modules, with a central command device, but due to the home’s architecture wireless signals don’t propagate well from one end of the house to the other. The solution is to build a mesh network that will allow each module to act as a network node, receiving and passing on messages until they arrive at the target device. He’s trying to do this with cheap hardware, selecting the PIC 16F88 which boasts 7 KB or program memory and 368 bytes of ram. In the end it doesn’t take much code to get this running, it’s the concepts that take some time and research before you’ll be comfortable working with them.

[Thanks Oakkar7]

Pitch Shifter Makes Your Band Sing Higher

March 17, 2011 by Mike Szczys 23 Comments

[Markus Gritsch] tipped us off about this little module he built to shift the pitch of audio playback. It uses a PIC 24FJ along with a couple of LM386 amplifier chips to manage the input and output signals. At the push of a button, audio being fed through the device can be modulated to a different key without changing the playback rate. Here it’s being used with a iPod but because this device just sits between an audio source and a signal input we wonder if you can have some fun on the cellphone with this circuit?

Check out the video after the break to hear it in action. We must compliment [Markus] on his layout. We haven’t seen the underside of that protoboard but he’s done a great job of fitting everything into a small area. You can find the schematic for the circuit by following the link at the top of this feature. He took a picture of his hand-drawn plans which saves him time from laying it out with something like KiCAD but still gives us the details that we love to see with your projects.

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