Professor Mark Csele writes:
When your hobby is collecting old computers (including a few 6800 processors on old arcade machines), a logic analyzer proves invaluable to diagnose a multitiude of problems. This particular project is a blend of hardware, both discrete logic and microcontrollers, and software in both assembly code and C++. The actual analyzer was inspired from the original article “High Speed Logic Analyzer for Windows 95″ appearing in Circuit Cellar Dec. 97 pp. 46 by Francis Deck. The basic system uses a special FIFO chip (7204) which is dual-ported to store logic-state samples which are transferred into a PC and displayed using a Win-32 front-end. The original analyzer hardware, built back in 1998, featured a front-end written in BASIC however there are many shortcomings to this approach and the system ‘hangs’ if an invalid trigger channel is selected. In this updated project (now over twelve years old and updated many times), a multi-threaded Win-32 front-end was written allowing good user control of the hardware. The system shown here features a 50MS/s sample rate, 4K sample depth, a trigger system to start sampling on a rising or falling edge on any particular channel, 3.3V and 5V logic family compatibility, and a high-speed USB interface.
USB Logic Analyzer IV - [Link]
There are any number of projects for which it would be handy to animate LEDs from a PC. Not a microcontroller, but a full-on PC. Media — music and video — are a natural for PCs, and tools like Max/MSP and Processing are a natural for creating media-based software sketches. (We use “PC” here in the generic “personal computer” sense, not in opposition to Mac; Using a combination of Processing and Arduino, everything shown here runs as well on Mac or Linux as it does on a Windows system!)
As a first demonstration, we’ll build a simple “Ambilight ” clone. Ambilight is a feature of some Philips televisions that projects colored light onto the wall behind the display , synchronized with the content on the screen to create an immersive effect. The authentic Philips system is well-integrated into the TV and works from any video source. Our facsimile, being computer-driven, works specifically with media content from your PC. This means its perfect for watching Youtube, TV or Movies on your PC or playing games!
Adalight – Make your own DIY Arduino-powered ambient “Ambilight”-like lighting rig - [Link]
Put a voltage meter anywhere with this very handy display. These are often used by RC hobbyists for keeping track of batteries but we thought it would be great on a breadboard or enclosure.
Simply connect the red wire to the positive supply, and black to negative ground. The display has a microcontroller that will read the voltage, compare it to a stable reference and display the voltage with 0.1V precision on a 3-digit 7-segment display. It works from 3.2V up to 30V so it will be good for nearly any electronic project! The meter draws 3-4mA to power the microcontroller and display. This particular LED display is a nice vivid green, which we found very readable. Mounting tabs make this module easy to attach to any box or plate. [via]
Mini Volt Meter - [Link]
This articles describes about making a general purpose I/O board that is easy to construct and is very useful for rapid prototyping of microcontroller-based projects. The board basically contains the most frequently used I/O devices and peripherals such as LCD, EEPROM, tact switches, LEDs, buzzer, etc. All the necessary pins of the devices on the board are accessible through female headers that allows easy connection of the board to a breadboard circuit or other development boards using male jumper wires.
Experimenter’s I/O board - [Link]
Breadboards are a great tool for designing and testing electronics circuits. Here Embedded Lab suggest some plug-in modules that would make your breadboarding life easier. These modules serve very common functions but their use will not only reduces the number of wire connections on breadboard, but also expedite your prototyping and makes debugging of the circuit easier.
Breadboard modules for rapid prototyping of microcontroller projects - [Link]
The keyboard is the most common way for humans to input information into a computer. It has been around since before computers were main-stream and everyone was still using typewriters. Because of this prevalence in society, it’s important that we understand how to interface to the basic PS/2 keyboard.
This article will describe and show you an example of how to create a system capable of interacting with a keyboard in order to understand what keys have been pressed. The example system will be built on a breadboard using a PIC microcontroller to communicate with the keyboard and display output.
PS/2 Keyboard Interface - [Link]
This was actually the first time I ever needed to multiplex analog channels so it was a good opportunity to learn how to use them. My task was to measure the temperature of 32 thermistors (NTC) with a microcontroller and later process that data. Obviously you cant find that much analog input channels on your common microcontroller so you need to multiplex the signals. First I looked for large analog multiplexers with 16 input channels but those are way too expensive. As it turns out its cheaper to use more smaller 8ch multiplexers(example Digikey pricing: 2pcs 16:1 mux from TI is $7.84 while 3pcs of 8:1 mux from TI is $1.53). I was able to get the 74HC4051 at a good price so I started creating the design around it.
74HC4051 Analog Multiplexer - [Link]
A lot of times we need to keep track of data from a device or a sensor located in a remote location from the point where it is processed. In other situations we desire wireless solutions for ease. Using long cables, infrared (IR) or other means are often tedious and not loss-less. Imagine collecting pH level data from a chemically lethal or toxic treatment plant where human presence is highly health hazardous. Running long cables from the pH sensor to the control or monitor station will surely introduce noisy signals and signal-to-noise ratio will thus drastically decrease. The result is erroneous data acquisition and thereby false decisions may be generated. If infrared signals or other optical means including lasers are used, they will need good obstacle-free line of sight or expensive and delicate optical fibers. Thus the solution stays in the radio frequency (RF) domain. This article talks about interfacing low cost RF modules (KST-TX01 and KST-RX806) for transmitting data between two remotely located PIC microcontrollers.
Wireless data transmission between two microcontrollers using KST-TX01 and KST-RX806 rf modules - [Link]
Rob writes in… [via]
I’ve seen quite a few hacks related to controlling appliances, lights, etc over the years and just wanted to share a little info so that everyone has access to a cheap way to do it relatively safely. By trade I work in the building controls/integration industry and as a result I use these relays at work and at home(chicken coop control,light,etc)quite a bit.
The interface between your microcontroller of choice and the relay is a simple 555 relay driver circuit. I have included the pdf that inspired me to do it this way. The relay I use is the RIBTU1C. The reason I prefer this relay is that the coil will run on 9VC @ 20mA and the contacts will switch 10A @ 120VAC. Total cost for the RIB and a 555 is under $15 if you shop around. In addition the RIB has a partition inside the box between the line and control sides. There’s also room for a Radio Shack breadboard in there!
Safety First! Switching 120vac loads with a microcontroller - [Link]
PIC microcontrollers’ Sleep feature is an extremely useful mechanism to minimize power consumption in battery-powered applications. This experimental tutorial from Embedded Lab describes how to put a PIC microcontroller into Sleep mode and then compares the PIC current consumption during Sleep mode and the normal operation mode.
Sleep and Wake PIC microcontrollers - [Link]