What do you do when you want to rock out on your keytar without the constraints of cables and wires? You make your own wireless keytar of course! In order to get the job done, [kr1st0f] built a logic translator circuit. This allows him to transmit MIDI signals directly from a MIDI keyboard to a remote system using XBEE.
[kr1st0f] started with a MIDI keyboard that had the old style MIDI interface with a 5 pin DIN connector. Many new keyboards only have a USB interface, and that would have complicated things. The main circuit uses an optoisolator and a logic converter to get the job done. The MIDI signals are converted from the standard 5V logic to 3.3V in order to work with the XBEE.
The XBEE itself also needed to be configured in order for this circuit to work properly. MIDI signals operate at a rate of 31,250 bits per second. The XBEE, on the other hand, works by default at 9,600 bps. [kr1st0f] first had to reconfigure the XBEE to run at the MIDI bit rate. He did this by connecting to the XBEE over a Serial interface and using a series of AT commands. He also had to configure proper ID numbers into the XBEE modules. When all is said and done, his new transmitter circuit can transmit the MIDI signals wirelessly to a receiver circuit which is hooked up to a computer.
When I was in the 4th grade our teacher announced that we had a special guest visiting us from somewhere “Far, far away…” As we piled out of the classroom and into to the courtyard, my jaw hit the floor – It was R2D2! The droid started to move around, and made all the noises like the movie. I couldn’t believe what I was seeing. R2D2 was real, and he was right in front of me! (My young mind made the conclusion that if R2D2 was real, then all of Star Wars was real.) I had to turn around to see my friends’ reactions. Unfortunately, it’s at that moment, I saw a middle-aged man, holding a RC transmitter, with antenna extended, standing in the background operating the controls. Sigh. R2 wasn’t real – it’s just a remote-controlled robot. My dreams of becoming a Jedi were forever crushed.
[Chris James] of the R2 Builders Club has been working hard to make a pair of “Stealth RC” controllers to help keep the magic of R2D2 intact. These dual joystick, 3D printed, hand-held units can be easily hidden in the palm of your hand, or the front pockets of a loose jacket while you operate them. Loaded with features, these tiny controllers use XBee radios to talk to a receiver and custom PCB inside the droid, that in turn, can then control dozens of servos, motors, sound playback and more. Because some R2D2 builds will have dozens and dozens of functions, rather than have a button for each one, [Chris] has programmed in gesture controls in to the unit, so that two controllers and can control several dozen preprogrammed actions. [Chris] hasn’t finalized the design just yet – he still calls it a “beta” build, but so far his documentation is outstanding (PDF) – some of the best we’ve seen.
You can learn more about the R2 Builders Club and the controllers in the video after the break
Continue reading “These Are The Droid Controllers You’ve Been Looking For”
[Bithead942’s] love of the ever popular Dr Who series led her to develop a replica of the 4th Doctor’s robotic companion. It’s name is K-9, and was built from scratch in only 4 months. Its shell is made from HPDE – a light and bendable plastic. A custom plastic bender was constructed to get the angles just right, and custom laser cut parts were used in various places.
Its frame consists of aluminum channel, and is packed full of juicy electronics. An arduino with an XBee shield controls the remote voice, frickin’ laser and eye sensors. Another arduino is paired with a motor shield to control the linear actuator for the neck movement. And a Raspberry Pi keeps the LCD screen in order.
We’re not done, folks. Because this puppy is radio controlled, a custom controller is needed. Sparkfun’s Fio paired with another XBee is used along with a 16×2 LCD and various other electronics to keep the robot on an invisible leash.
Be sure to check out the blog site, as it goes into great detail on all the various parts used to construct this complicated but awesome project.
[Bob] was having trouble keeping up with his water troughs. He had to constantly check them to make sure they weren’t empty, and he always found that the water level was lower than he thought. He decided it was time to build his own solution to this problem. What he ended up with was a water level sensor made from PVC pipe and a few other components.
The physical assembly is pretty simple. The whole structure is made from 1/2″ PVC pipe and fittings and is broken into four nearly identical sensor modules. The sensors have an electrode on either side. The electrodes are made from PVC end caps, sanded down flat at the tip. A hole is then drilled through the cap to accommodate a small machine screw. The screw threads are coated in joint compound before the screw is driven into the hole, creating its own threads. These caps are placed onto small sections of PVC pipe, which in turn connect to a four-way PVC cross connector.
On the inside of the electrode cap, two washers are placed onto the screw. A stranded wire is placed between the washers and then clamped in place with a nut. All of the modules are connected together with a few inches of pipe. [Bob] measured this out so it would fit appropriately into his trough, but the measurements can easily be altered to fit just about any size container. The wires all route up through the pipe. The PVC pipe is cemented together to keep the water out. The joint compound prevents any leaks at the electrodes.
A piece of CAT 5 cable connects the electrodes to the electronics inside of the waterproof controller box. The electronics are simple. It’s just a simple piece of perfboard with an XBee and a few transistors. The XBee can detect the water level by testing for a closed circuit between the two electrodes of any sensor module. The water acts as a sort of switch that closes the circuit. When the water gets too low, the circuit opens and [Bob] knows that the water level has lowered. The XBee is connected to a directional 2.4GHz antenna to ensure the signal reaches the laptop several acres away. Continue reading “Wireless Water Level Sensor from PVC Pipe”
Radio, WiFi and similar modules are getting smaller by the day. Trouble is, they end up having non-DIY-friendly, odd pitch, mounting pads. Sometimes, though, simple hacks come around to help save the day.
[Hemal] over at Black Electronics came up with a hack to convert odd-pitch modules to standard 2.54mm / 0.1″. The process looks simple once you see the detailed pictures on his blog. He’s using the technique to add 2mm pitch modules like the ESP8266 and XBee by soldering them to standard perf board. Once they are hooked to the board, just add a row of male header pins, trim the perf board and you’re done. Couldn’t get simpler.
Another technique that we’ve seen is to solder straight across the legs and cut the wire afterward. That technique is also for protoyping board, but custom-sized breakout boards are one good reason to still keep those etchants hanging around. If you have other techniques or hacks for doing this, let us know in the comments.
When you move into an old house, you are bound to have some home repairs in your future. [Ben] discovered this after moving into his home, built in 1929. The house had a mail slot that was in pretty bad shape. The slot was rusted and stuck open, it was covered in old nasty caulk, and it had a built-in doorbell that was no longer functional. [Ben] took it upon himself to fix it up.
The first thing on the agenda was to fix the doorbell. After removing the old one, [Ben] was able to expose the original cloth-insulated wiring. He managed to trace the wires back to his basement and, to his surprise, they seemed to be functional. He replaced the old doorbell button with a new momentary button and then hooked up a DIY doorbell using an XBee radio. [Ben] already had an XBee base station for his Raspberry Pi, so he was wrote a script that could send a notification to his phone whenever the doorbell was pushed.
Unfortunately, the old wiring just didn’t hold up. The push button only worked sporadically. [Ben] ended up purchasing an off the shelf wireless doorbell. He didn’t want to have to stick the included ugly plastic button onto the front of his house though, so [Ben] had to figure out how to trigger the new doorbell using the nice metallic button. He used the macro lens on his iPhone to follow the traces on the PCB until he was able to locate the correct points to trigger the doorbell. Then it was just a matter of a quick soldering job and he had a functional doorbell.
Once the electronics upgrades were complete, he moved on to fixing up the look of the mail slot. He had to remove the rust using a wire brush and sandpaper. Then he gave it a few coats of paint. He replaced the original natural insulation with some spray foam, and removed all the old nasty caulk. The final product looks as good as new and now includes a functional wireless doorbell.
We’re big fans of salvaging old-school home hardware. Another example that comes to mind is this set of door chimes with modernized driver.