UDP between STM32-F4 Discovery boards


[The Backwoods Engineer] tested out a new accessory kit for the STM32-F4 Discovery board. The image above shows two boards communicating with the UDP protocol. Notice the extra PCB into which each Discovery board has been plugged. This is a third-party add-on which adds Ethernet, RS-232, SD card slot, and a connector for LCD or Camera. We’ve had one of these F4 Discovery boards on hand for a while and haven’t figured out a good way to connect external hardware to the huge dual pin-headers. This doesn’t solve the problem — the base board also includes dual headers to break-out all the pins — but having Ethernet, serial, and SD certainly reduces the need to add all that much more. The other drawback to the hardware is that the sample firmware is targeted at the IAR Embedded Workbench which is neither free, nor in the realm of affordable for hobbyists.

The NIC used on the baseboard has auto-crossover capabilities so the boards were connected using a regular Cat6 patch cable. This example has the boards constantly sending UDP packets with the module on the right reporting status information to a terminal via the serial connection.

Airsoft turret has turn, tilt, and auto-feed to keep those BBs flying


Yet another project that proves you need to acquire a laser cutter. This Airsoft turret rotates, tilts, and includes a hopper for ammo.

All of the pieces were cut from acrylic. The base includes a bracket which keeps the large rotating gear level by sandwiching it between the layers. That and the tilt mechanism are pretty straight forward. The module responsible for loading the BBs is pretty neat though. It uses a gear with round teeth the same diameter as the ammo. Once a BB is picked up it is forced upward into the tubing that feeds the gun. Get the full picture from the demo video after the break.

The one thing [The Liquider] is wondering about is how to provide feedback for the tilt and rotate functions. We can’t think of an easier way than to use simple rotary encoders. The Arduino Mega he wishes to use as a driver will have no problem interfacing with reflectance sensors and the acrylic makes it simple to mount this type of black and white encoder wheel.

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Cracking open a 24-port switch so you don’t have to


[Kenneth Finnegan’s] post about this 24-Port HP ProCurve 2824 Ethernet Switch teardown was a delight to read. He’s taking an introduction to networking class at California Polytechnic State University. One of their labs included virtual machines shooting thousands of new MAC addresses at the thing all at once. Despite it’s ability to switch data at a blazing fast rate, it’s ability to deal with that many new hardware identifiers was less than impressive. He wanted to find out why and it just so happened he had one of these in his parts bin at home (which he refers to as if it’s a high-powered RPG character).

The mainboard is divided into three major blocks: the power supply, the switching hardware, and the processor that makes this a manged switch. Although he covers all of these pieces (and the switching stuff is very interesting to learn about) it is the processor section that was causing the aforementioned slowdown. It’s a 266MHz PowerPC chip with a measly 64 MB of RAM. Of course this doesn’t need to be any more powerful since all traffic from previously ‘learned’ MAC addresses gets handled by the switching block and never touches the processor portion.

Don’t miss the end of his post where he discusses how the filtering caps, and semi-isolated ground planes help to tame the beast created from all of this high-speed switching.

Beginner’s Android/Arduino example shows the power of App Inventor

This is a simple project. It uses an Android device to switch an LED driven by the Arduino. Connectivity is provided by the Bluetooth module inserted in the breadboard. But one look at the UI on the Android device and you might think this is anything but simple. The truth is that [Kerimil] didn’t spend forever learning Java and programming the app. Instead he’s showing off the power of  App Inventor to get your Android controls up and running fast.

Check out the third button down; when was the last time you added voice commands to your project? It’s worth clicking through to see just how simple that portion was. App Inventor — a Google cast-out that is now maintained by MIT — is a graphical tool that unlocks the power of an Android handset to those with the most basic of programming understanding. For instance, the voice controls shown off after the break are provided by a single bracket which uses conditional statements to ‘listen’ for the words on, off, and blink. You’ll find the voice recognition diagram after the break as well.

You could try to go completely graphical with this project. There’s the option of programming the Arduino side of the project in a similar way.

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Quadcopter brain


This project is the warm center of [Alan Kharsansky’s] thesis in Electronic Engineering. It’s an all-in-one control board for a quadcopter. This is the second iteration of the board, the first version he actually etched himself. As you can see after the break the firmware is not quite ready for prime-time. But that doesn’t stop us from appreciating the design choices he’s made.

You can see the effort he made to keep the board symmetrical which will help when it comes time to balance the aircraft. At the center of the PCB is the jewel of the sensor array, a combination accelerometer and gyroscope. This location will help easy the trouble of designing PID algorithms to drive the four propellers. Also included in the sensor array is a magnetometer for navigation, and a barometric pressure sensor which can be used as an altimeter. There are four multipurpose connectors used to drive the motors and provide feedback to the boards. He also included two more sets of pads on the board (without their own connectors) in case he wants to add more motors in the future. The quadcopter can be controlled from a base station via the XBee module.

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An awesome, futuristic, all-in-one robot chassis


No matter how many advances in electronics we find, we’re constantly surprised at the lack of progress in robot chassis. Sure, it should be a simple task to make a capable robot that looks cool, but aside from the Veter project team, no one else seems to be advancing the state of robot mechanics.

We’ve seen robotic chassis and hardware from the Veter team before, and this new version brings a whole lot more to the table. While the camera. GPS, compass, and ultrasonic sensors are the same from the previous build, there’s a whole lot more software inspired by [Sebastian Thrun]’s autonomous car class to make this build a little more capable.

While the Veter team is using a Beagleboard for their on-board computer, it should be possible to change the hardware over to a more economical Raspberry Pi. Even then, it won’t be a cheap build, but we doubt you’ll find a better robotics platform for less.

Pulse jet snowmobile, or, what Swedes do during hibernation

jetSweden is coming out of the depths of a cold, dark winter. What better time, then, to enjoy the last few weeks of frigid temperatures, short days, and frozen lakes and rivers? That’s what Orsa Speed Weekend is all about; tearing across a frozen lake by any means necessary, including jet powered snowmobiles.

This pulse jet comes from the fruitful minds at Svarthalet Racing (Google Translation) who have put an amazing amount of work into their fuel-injected pulse jet snowmobile during these last cold winter months. They’ve even gone so far as to do some analysis regarding how much horsepower their snowmobile has. Surprisingly, it’s not much more horsepower than a small car, but that’s due to the hilarious inefficiency of pulse jets compared to more conventional engines.

This isn’t the first time we’ve seen jet powered snowmobiles build for Orsa Speed Weekend. We’ll just hope this year a few more videos will show up in our tip line.