The world of hobby electronics have only started putting USB in projects for the last few years, and right now, pushing 1.5 Mbps down a USB port is good enough for most cases. This isn’t true for all cases; that’s a terrible data rate, really, and to get the most out of a USB connection, you can at least move up to USB Full Speed and 12 Mbps.
[Linas] is using the STM32F4 microcontroller for this example, an extremely large and very capable chip. [Linas] is using FTDI’s FT2232D USB UART to send data from an SPI port over USB. This chip does support 12 Mbps, but only after a few additions; an external EEPROM must be connected to the FTDI chip to provide a USB 2.0 device descriptor, otherwise the connection between the microcontroller and a computer is limited to 1.5 Mbps. Even using the USB on the STM32 would be a bottleneck in this case; [Linas] is moving data out of the processor using only the DMA controller – using the USB on the STM32 would eat up processor cycles in the microcontroller.
Thanks to the DMA controller inside the STM32, the microcontroller is capable of sending and receiving data through SPI at the same time. The STM32 is capable of reading and writing to the Tx and Rx buffer at the same time, but the computer is only capable of half-duplex operation – it can only read or write at any one time. [Linas] is setting up the DMA controller on the STM32 as a circular mode, putting everything in the buffer into the FTDI chip, and reading everything sent from the computer back into the STM32’s memory. After counting off the correct number of packets. the controller resets everything, moves the circular buffer back to the beginning, and starts the whole process over again.
The circuit was prototyped with an STM Discovery board. With Labview, [Linas] can see the bits coming out of the microcontroller, and send some bits back to the micro over USB. [Linas] has an extraordinarily detailed video tutorial on this project. You can check that out below.
Continue reading “12 Mbps Communication Between A PC and MCU”
[Gregory Charvat] continues to have a great time testing out radar systems. He and a friend have pointed the radar out the garage door and are using it to see who can reach a high running velocity.
The last time we looked in on [Greg’s] work he had acquired an old police radar unit and wired it up to use with a laptop. The hardware he’s working with now is a lot more bulky and we don’t think it will be hitting the road with him anytime soon (although it is on wheels). The video after the break starts off which an overview of the test system which is mounted in a waist-high rack. He illustrates how Labview is monitoring the radar inputs and then moves on to show off the hardware which is actually harvesting the data. The box is quite versatile, able to run five different systems and includes a slew of different connector types.
Continue reading “More continuous wave radar fun”
The gang over at Waterloo Labs decided to add a team-building aspect to a plain old Etch a Sketch. Instead of just twisting the two knobs with your own mitts, they’re converting this giant pencil’s movements into Etch a Sketch art.
The challenge here is figuring out a reliable way to track the tip of the pencil as it moves through the air. You may have already guess that they are using a Microsoft Kinect depth camera for this task. The Windows SDK for the device actually has a wrapper that helps it to play nicely with LabView, where the data is converted to position commands for the display.
On the Etch a Sketch side of things they’ve chosen the time-tested technique of adding gears and stepper motors to each of the toy’s knobs. As you can see from the video after the break, the results are mixed. We’d say from the CNC ‘W’ demo that is shown there’s room for improvement when it comes to the motor driver. We can’t really tell if the Kinect data translation is working as intended or not. But we say load it up and bring to a conference. We’re sure it’ll attract a lot of attention just like this giant version did.
Continue reading “Giant pencil used as an Etch a Sketch stylus”
In an effort listen to his music on shuffle without the need to touch the volume knob [Mike] build his own automatic volume leveling hardware. He knows what you’re thinking right now: there’s software to do that for you. But building the feature in hardware is a great stepping off point for a project.
He started the prototype using LabVIEW along with a Mobile Studio development board and a Bus Pirate. This project will be a mix of digital and analog components and it’s a bit easier starting off the exploration with these tools rather than jumping right into the AVR code.
The circuit will sample the incoming audio, modify it accordingly, and output the result. The output side is where the Bus Pirate really shines. He’s using some MCP42010 digital potentiometer chips to make the necessary changes to the levels. They communicate via SPI and it’s nice to have the Bus Pirate’s terminal to issue commands without the need to reflash a microcontroller.
[Mike] made a video showing an audio waveform with and without the hardware leveling. Sound quality is still great, and each clip is played at a reasonably comfortable listening level. We’ve embedded that demonstration after the break.
Continue reading “Microcontroller based audio volume level compressor”
Ah, the end of the 4th financial quarter – the magical time of increased sales, being at work the entire time the sun is up, and holiday parties. For [Andy] at National Instruments, though, things don’t seem too bad. He built a neat Christmas light suit to entertain everyone with his brilliant persona.
[Andy] always loves great Christmas light displays (he even blogs about them), so he figured a wearable light display synchronized with music would be very doable. The build is controlled with LabVIEW to convert .WAV files to power levels and frequency bands. This info is then piped into the Arduino that controls the lights.
[Andy] actually made two light suits, one for him and one for his friend [Richard]. Both guys have two light-up Christmas staffs to wield light mage powers on their coworkers. The lighsuits are controlled by Arduino/Xbee setups – one each for each suit and staff. The result is phenomenal, and should really get everyone in the holiday spirit.
Over 100,000 Lego pieces, 4 people a year to create, and a 12 foot by 12 foot chess board make this the largest most awesome Lego hack we’ve ever seen. Take that Lego Printer.
For a mere $30,000 you too can have such a setup. Not a lot of information is out yet, but we do know all the pieces are remote controlled via a PC with LabVIEW and a total of 38 NXT controllers are used. Oh, and of course you can see it live at the 2010 Brickworld. Check out a video of a replayed game after the jump.
Continue reading “Monster Chess”
Props go to [Michael Nash] for establishing an interface between National Instrument’s labVIEW and an Arduino (an example video using a potentiometer is above). Personally, from the one time we were forced to use labVIEW, we hated every second of it.
One reason it’s so terrible, is the Data Acquisition Modules cost well into the hundreds of dollars, yet the documentation and help resources are very scarce. By using an Arduino instead of the modules, the price and difficulty decrease a considerable amount. Which begs the question why has it taken so long to get a decent (and so simple) of a setup working?