USB infrared receiver looks good sitting in your livingroom


The problem with building your own electronics for the living room is that the final product may not fit your decorating style. This was true with [Itay's] prototype of a universal USB IR receiver. So after testing it out for a few weeks he decided to build a final version that started by selecting an enclosure he could be proud of.

He came across an LED flash light at the dollar store which has an aluminum body. When we read about this we envisioned a cheap version of a Mag Light from which he removed the cylinder that holds the batteries. But actually, the pod seen above is the entire flashlight (with an added base). It forced him to design a tiny surface mount PCB to fit everything inside.

It’s not too much of a stretch since IR receivers tend to be small anyway. [Itay's] design put a PIC 18F2553 on one side of the board. The other side hosted the through hole components: an IR receiver, LED for feedback, and the connections for the USB cable that exit through the rubber button cover that used to switch the flashlight on. He had a problem with one of the resistor values which took a while to figure out. But eventually he got it working. It’s been in use now for six months.

Wristwatch made of sandwiched PCBs


Here’s a wristwatch concept we haven’t seen before. Instead of trying to sandwich everything inside of a case it uses a stack of PCBs as the body of the watch.

[Mats Engstrom] wrote in to tip us off about his build. The design goes with LEDs which is nothing new. But unlike previous offerings [Mats] didn’t go with one LED for each minute. When the touch sensor in the middle of the watch is activated the twelve LEDs on the face will let you know the hour and the nearest five minutes. A video of this is embedded after the break.

The design uses three different circuit boards. The bottom board is the largest and provides slots through which the wrist bands can connect. It also serves as one of the two battery connectors. The second PCB is a spacer with a cutout for the coin cell that powers the device. The top board is where all the magic happens. It’s dual sided to host the LEDs and touch senor, with the PIC microcontroller and support circuitry on the other side.

[Read more...]

Perpetual pong


[Jeff Joray] wrote in to show off this perpetual Pong device he built. The six by ten LED matrix acts as a game board for Pong but there are no controls. The board simply plays against itself. It’s pretty much a pong clock without the clock.

The brain of the device is a PIC 16F684 which drives the six rows of the display directly. He went with a decade counter (CD74HC401) to scan the rows one at a time. Now what would you expect to find on the underside of this hunk of protoboard? A rat’s nest of point to point wiring? If so you’re going to be disappointed. [Jeff] spent the time to generate a schematic and board layout in Eagle. While at it, he knew he was going to be using protoboard so the artwork is designed to use solder bridging as much as possible. What he ends up with is one of the cleanest mutiplexed one-off projects you’re going to find. See it in action after the jump.

[Read more...]

MP3/USB/Aux hack hidden behind cassette facade


[Ivan] made something special with this car stereo hack. He altered the head unit to play MP3 files from USB and added an auxiliary line-in. But looking at it you’d never know. That’s thanks to the work he did to create a false button hiding the audio jack, and a false cassette hiding the USB port and MP3 player display. Possibly the best part is that the radio itself still works like it always did.

There are several components that went into making the system work. It starts with the cassette/radio head unit. To that he added an MP3 player with remote which he picked up on Deal Extreme. He wasn’t a huge fan of the IR remote that came with it so he rolled in a remote that mounts on the steering wheel. To pull everything together he used a PIC 16F877a. The microcontroller controls the lines which tell the head unit if a tape has been inserted. When [Ivan] selects either the Aux input or wants to play MP3s from a thumb drive the uC forces the head unit into cassette mode and the audio from the player is injected into the cassette player connections.

To help deter theft [Ivan] created two false fronts. The end of a cassette tape plugs into the USB port. The rewind button plugs into the Aux jack. You can get a good look at both in the demo after the break.

[Read more...]

A homebrew binary wristwatch


There are 2 types of people in the world; those who know binary, those who don’t, and those who know ternary. [Emanuele] thought a binary wristwatch is the pinnacle of nerd and set out to build his own. The resulting binary clock not only screams nerd as intended, but is also a functional time piece, as well.

The idea of a binary wristwatch came to [Emanuele] while he was working with PICs at school. Not wanting to let that knowledge go to waste, he used a PIC16F628 microcontroller for this build. There are four LEDs for the hours and six LEDs for the minutes, each attached to a separate microcontroller pin for easy programming.

To keep time, [Emanuele] kept the PIC in sleep mode most of the time, only waking it up when a an internal timer’s register overflows. The watch spends most of its time sleeping, sipping power from a coin cell battery with a battery life that should last weeks, at least.

The entire circuit is tucked away in a PVC enclosure with a wonderful rainbow ribbon cable band. We’re not so sure about how that feels against the skin all day, but it does exude the nerd cred [Emanuele] was looking for.

Fabricating custom displays for a commercial coffee roaster


Roasting the perfect coffee bean is an art form. But even the most talented of roasters can use a little feedback on what’s going on with their equipment. [Ludzinc] recently helped out a friend of his by building this set of 7-segment displays to show what’s happening with this coffee roaster.

The yellow modules hiding underneath the display panel are responsible for setting the speed of the hot air blower and the rate at which the drum turns. They’re adjustable using some trimpots, but it sounds like the stock machine doesn’t give any type of speed feedback other than direct observation.

The solution was to patch into those speed controllers using the ADC of a PIC chip. They each output 0-10V, which [Ludzinc] measures via a voltage divider. After the speed is quantified the microcontroller outputs to one of the displays. Since there’s a different chip for each readout, the firmware can be custom tuned to suit the operator’s needs.

Keep this in mind if you’re still planning to build that coffee roaster out of a washing machine.

Another salvo in the PIC vs. AVR holy war

holy war

Ah, PIC vs. AVR, the never-ending battle of electronic design supremacy. Some people swear by Atmel’s AVR microcontrollers, while others are wrong. [majenko] is firmly planted in Microchip’s PIC camp, so he wrote up a nice comparison of Atmel’s AVR versus Microchip’s PIC family of microcontrollers. The results aren’t that surprising; PIC microcontrollers come out as a better product that no hobbyist uses because no hobbyist uses them.

Atmel and their series of AVR microcontrollers has seen a huge increase in popularity in the hobbyist market in the last few years, no doubt thanks to the Arduino and other AVR-powered dev boards. This isn’t to say Microchip and PIC haven’t seen their time in the lime light; there was a time when you could actually buy electronic components at Radio Shack, including kits containing Microchip’s very popular but somewhat outdated Basic Stamp.

After going over the capabilities of the Atmel AVR ATMega328p, the similarly equipped Microchip’s PIC PIC18F25K80, and TI’s MSP430G2533, [majenko] found the perennial favorite, the AVR, lacked in some very important categories. The AVR has a lower resolution ADC, fewer PWM pins, fewer 16-bit timers, while costing about $0.75 more.

Of course [majenko]‘s analysis doesn’t take into account the intangibles of choosing a PIC over an AVR. Thanks to the Arduino’s adoption of the AVR, there are many, many more code and schematic examples floating around on the Internet for just about every project imaginable. The development tools for PIC are a bit more expensive than their AVR equivalents; A PICkit2 runs about $50 while AVR ISP programmers can be found just about everywhere for pocket change.

It’s a lazy Sunday, so all ‘yall can go on and argue in the comments.


Get every new post delivered to your Inbox.

Join 91,896 other followers