Hello FPGA hobbyists! Ever wondered what it would be like to see sound? The author thveryat very same curiosity for close to 10 years, and kept a constant vigilance for ideas to build something that would help him materialize his dreams. The Daredevil camera, built using a bunch of MEMS microphones and a FPGA actually lets you see sound.
The author started the project wielding inspiration from the Duga RADAR. However, the scale of the project becomes huge and something beyond what hobbyists can afford. The author then tried a more practical but tedious and time consuming design approach which involved using an array of microphones. Each microphone in the array picks the sound relative to its position and displays it on screen, which will always be different from the next microphone because of the difference in position.
While the logic behind this is sound, implementing an array of microphones, each having a Pre-amp stage and then an ADC stage before feeding inputs to the FPGA is not practical. The cost and time put into the project becomes huge, and even then error margins can be significantly high.
This is the reason why the author used a set of MEMS microphones. MEMS microphones have an inbuilt Pre-amp and ADC stage, and thus the project collapses in complexity. All that is needed is an array of MEMS microphones and an FPGA board to implement the project. FPGAs are FFT friendly and this has a huge part in the project.
The author has shared the PCB design layout here. Besides this a number of fail safes such as spare patterns for a Flash chip, SOIC and DIP. He also used micro SD cards for each array to store the data and send it for processing to get an output of close to 30 frames per second. The FPGA, a great tool for pipelining is used to get his output.
The author then tried out the theory in an 8×8 array and arrived at the conclusions that the device is pretty sensitive as it even picks up sound way reflections from surfaces. But since anechoic chambers are impossible to build at home, he went on to build a 16×16 array.
While the results can be seen in this page, the author is yet to perfect his design. There are persistent issues with micro SD card since its storage algorithm conveniently cuts off data to compress data, which is essential for the FPGA to build a 30 Frame/sec output.
To be heard…or seen.
In today´s article the author describes a project developed by one of the prize winners. What prize winners? What prize at all? Ok, let´s rewind a little here. The author talks wonders about Silego´s GPAK chip and so those guys were very excited about the interest generated that they decided to give the author 25 development kits of the GPAK4 (the prize). What could our starring character do with 25 dev kits on his hands??? He launched a contest and the 25 winners, those whose projects were most interesting, would win one of the dev kits.
Well, now that we all know what we are talking about…Wait, what is a GPAK4? Fair enough. A GPAK4 as the author defines it is “a super-small, mixed-signal FPGA that you can literally design and program in just a few minutes, and that cost only a few cents each”.
After this quick introduction, I would say that the article moves on to explaining some of the details of the logic design implemented on the GPAK4 FPGA for its multi-peripheral controller. The main advantages of implementing this tiny device are offloading the host MCU, saving GPIOs and simplifying PCB layouts. You will be able to see some of the simulation results and if you are interested you can download the whole design file here.
Stay tuned for the remaining 24 projects and for another giveaway…
Today´s post presents a great article for almost everybody. Whether you like real making from scratch, writing code or just working with an FPGA, keep reading.
Somehow the author was fascinated by LED digit displays at some point in his life and so he decided he had to build his own giant LED digit grid. The final design consists of 64 panels of 7-segment digits displays (8 taking into account the decimal point), a total of 4096 LEDs! These diodes are grouped by 16, each group having its own PCB with input and output headers and a LED driver/controller. Then the whole design is controlled by a Spartan 3E FPGA. This guy chose to write the animations on Processing and send them over the FPGA serial port. So you can see there are candies for every taste in this store.
Read the full article to find out that the first draft of the design did not include the use of an FPGA…In the end it did and so did the Verilog code.
The schematic and the layout are given so those who love the smell of the solder can get straight hands on. And code guys are also lucky, there is no Verilog provided and just an example of a processing sketch for displaying the first 512 digits of pi, so you can do what you love to.
Today´s article will teach you how to create your own FPGA-based tilt sensing device. It is one of those really thorough tutorials where almost nothing is left to your imagination but the infinite applications you may develop. Cool right?
This project is based around the DEo-Nano board and its built-in tilt sensor. I am pretty sure you know what a tilt sensor is, but do you know how it works? Read this to find out the real physics behind this highly useful tiny device.
Another cool thing you will learn if you invest some time reading this article is to create your own, home-made, PCBs. You need to build one in order to be able to access the I/O pins of your DEo-Nano board. Everything couldn´t be easy, otherwise it wouldn´t be challenging and so boring.
All the rest you need is given, schematics, parts lists, code…So, what´s left for you to do is the funny stuff: building things and playing!
Using a electronic design to mesh your mechanical design can be quite a difficult task. 3D printers come to the rescue to facilitate this process, especially when using an Eagle to design a PCB.
In the following post, the designer used several LEDs to build a clock which worked fine but there was a slight light leakage around his custom made 7 segment numbers. More information on this project in the link below.
When designing double-sided PCBs, Retromaster kept running into the same annoying problem: how in the world do I set my vias without them sticking out too much? A via must protrude from the board only very little, otherwise it cannot be placed under an IC. So placing copper wire in the via hole and soldering both ends is out. In light of this, Retromaster came up with a great solution. Use some copper wire and a vice. Sounds easy enough, right? Fantastic news – it is!
The best solution I’ve come up with so far is using “mechanical vias”. In a nutshell, I place a small piece of copper wire in the via hole. It needs to be a tight fit so that it won’t slip out of the hole. I trim the ends of the wire so that very little (perhaps less than a millimeter) of it sticks out of the hole in both sides. Then, I place the board in something like a vice (what I referred to as a “via press” …) and applying pressure to the board crushes both ends of the copper via and produces what seems like a reliable connection between the two sides.
It’s really simple to set one of these “via presses” up. Pretty much all you need for instructions on this is to refer to the picture above, and make sure you’re using steel plates on your vice which your PCB will be sandwiched in between. This is just to ensure that the copper wire gets crushed correctly, as the steel plates are harder than the copper wiring.