USB Gameboy Cart

August 28, 2009 by Zach Banks 20 Comments

gamecart

[Jose Torres] sent in his latest attempt at creating a custom Gameboy game cartridge. We’ve featured his projects before, and he’s come a lot closer over the last 2 years. He’s aiming to create an easy interface for homebrewers that doesn’t require any other special equipment. In this revision, he’s using a PIC and a memory controller to interface between an SD card and the Gameboy. The cart also has USB support for uploading files to the SD card and reprogramming the PIC. Because it’s just USB mass storage, it will work on almost any modern OS. He’s currently testing the device, but hopes to be selling them soon for $40.

Interfacing A Digital Rotary Switch

August 27, 2009 by Mike Szczys 19 Comments

digital_rotary_switch

[hw640] has put together a well written and detail packed explanation of how to interface with a digital rotary switch. These digital opto encoders have just two outputs with four possible logic levels (00, 10, 11, 01). The relative position of the switch is insignificant but the direction of rotation is what matters.

The short and dirty: Each of the switch’s 2 output pins is attached to a pin change interrupt on the microcontroller. Every time the switch moves it generates either a rising edge or a falling edge on one of the two pins; both edges cause an interrupt. By checking which pin caused the interrupt, then comparing the logic levels of the two pins after that interrupt, we can determine the direction the switch was rotated.

Although this explanation uses a PIC and code written in PicBasic Pro the concepts are discussed in the abstract and would easily be adapted to an AVR or another microcontroller of your choice.

Adding A DisplayLink Monitor To A Linux Router

August 24, 2009 by Matt Schulz 14 Comments

slugterm_dl

Routers aren’t just for routing network traffic any more. With the help of alternative operating systems such as DD-WRT, Tomato, and OpenWrt, routers are now extremely customizable and can be utilized to suit a number of needs. The main issue with projects built around routers is the need to telnet or SSH into them to get to a console. [Sven Killig] came up with a useful solution that utilizes the USB ports available on an Asus router to display video on a DisplayLink device, allowing a user to sit down and use the device as though it were a physical terminal. This would be a good DIY alternative to commercially available routers that display network graphs, system information, incoming email, and other data.

Klipsch Speaker Mods

August 23, 2009 by Caleb Kraft 8 Comments

P1010021 (Custom)

[Patrick] has a pair of Klipsch speakers that continually needed the volume knob cleaned. After a bit of research, he found it was a common problem with the potentiometer chosen for the task. He decided to resolve the problem, not by replacing that potentiometer, but by modifying the speakers to be passive and running them from an external amp. While this does sound simple at first, he wanted to retain the rest of the electronics in the unit, so a bit of hacking was required. You can follow along through the whole process on his site.

Second Hard Drive In A Macbook Pro

August 23, 2009 by Caleb Kraft 23 Comments

Picture 4 (Custom)

[Reid] wrote in to show us how to add a second hard drive to his Macbook Pro. He found that he hardly ever used his DVD drive, so sacrificed it in favor of added storage. What he found was that it had a proprietary adapter that he was unable to find for sale anywhere. Making an adapter may seem like a pretty simple hack, but this could save some people considerable time. Its also worth noting that upgrading the firmware got him an 18% speed increase, so don’t ignore those updates. We don’t see too many mac hacks around here, you may recall the mac tablet hacks and the logo monitor.

Collect And Analyze ECG Data

August 22, 2009 by Zach Banks 14 Comments

ecg

Although we’ve covered DIY ECGs before, [Scott Harden] sent in his version that gives an in-depth explanation of what to do with the collected data. He built a basic battery-powered op-amp-based ECG for under $1. The circuit just amplifies the signal from the chest leads and feeds it into a computer via the microphone port. He then used GoldWave to record, filter, and save the signal. From there, he used python to analyze the heartbeat and calculate his heart rate and further manipulate the data. His previous blog posts go into more detail on how the python code works and why he chose software over hardware filters.

Arduino USB Host Shield

August 21, 2009 by Phil Burgess 18 Comments

UsbHostShield

Circuits@Home has been journaling their development of a USB host mode shield for Arduino, which could bring the platform a veritable explosion of mass storage, keyboard input and countless other peripheral options (and a corresponding raft of new hacks). Currently at the prototype stage, a ready-made shield and library are forthcoming, so keep checking back. Meanwhile, for embedded developers wanting to learn the ropes of USB, the in-progress articles will likely provide some valuable insights.

[thanks Kersny]