Robot K-9 Scares Off the Daleks

[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.

Wireless Water Level Sensor from PVC Pipe

[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”

Castellated Breakout is Pitchin’ Brilliant!

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.

Water Tank Monitoring System Is Now Slug-Proof

[Peter] is doing his part toward protecting the environment and conserving water. He’s built a rainwater collection system complete with an underground storage tank. Since he wanted to monitor the water level in the tank, he made a level indicating system. Everything was going well until one day out of nowhere it stopped working, only returning 0’s as the level. [Peter] took a look and found that I slug had made its way into the electronics enclosure and slimed up the traces on the PCB, causing short circuits.To fix the problem [Peter] decided to redesigned the system. This time it would be built into an all-weather electrical box. The system uses a standard hobby ultrasonic range finder to measure the distance from the top of the tank to the level of the water. Two holes cut into the electrical box allow the sender/receiver components to peek outside of the enclosure. Any gaps were then filled with sealant. [Peter] also added a thermistor to measure the temperature inside the tank.The sensor values are read by an Arduino and sent wirelessly to [Peter]’s computer via a pair of XBee’s and a second Arduino with an ethernet shield. The data are sent in 3 minute intervals and automatically stored in a MySQL database for quick reference of level and temperature trends. Now [Peter] can monitor his rain water remotely and adjust his usage habits accordingly. Want to read more about water tanks? Check out this overflow monitor system.

A 1920’s Doorbell is Upgraded with 2010’s Technology

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.

THP Semifinalist: Honeybee Hive Monitoring

[Ken] keeps his bees remotely and can’t check on them as often as he might like to. He wanted some way of knowing when they were out of space, because that slows down their nectar collection. He knew he could do this by remotely tracking the weight and internal temperature of the hives.

His first prototype revolved around a postal scale that couldn’t be turned off between readings. This meant that he needed a bigger solar panel and battery than originally intended. For about a week, the hives were sending data to Thingspeak through an Arduino Fio over XBee.

The current iteration measures the load cells with an HX711 24-bit ADC. This sends the scale data to an Apitronics Bee unit, which adds in temperature data from the hives and sends everything to an Apitronics Hive. [Ken] will also stream it to a cloud service so he can monitor them in real-time. [Ken] wants to see as much data as possible and contribute to NASA’s HoneyBeeNet program, so he has a second Bee unit set up to handle a nearby Apitronics weather station.

SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize.

Changing Poi Colors Based on Speed and Velocity

LED toys have become synonymous with the underground rave culture as party-goers gaze into vortexes of spinning light known as poi. Most of these objects come pre-programmed, but some can be custom coded. However, only a few tap into an accelerometer changing the colorful circles of energy depending on how fast they move through space. One stunning example is this LED device called the ‘Center Flee’ that translates accelerometer data into sequences of alternating RGB colors.

The LED values are ‘printed’ to the tethered objects at specific points in the rotational arc. The devices are controlled with an Arduino, and a XBee wireless module transmits data to a computer nearby, eliminating the need to manually remove an SD card after each spinning session.

When spun, the poi acts like a colorful, twirling extension of the performer that produces a mesmerizing, vibrant effect. It’s nice to see the progression of glow sticks tied to shoelaces into g-force sensing devices that can captivate surrounding audiences.

Other examples of similar types of ideas include this accelerometer poi that was cut with a CNC machine and these LED staffs for the ultimate portable rave.

Below is a video playlist of the Center Flee being tested out.

Continue reading “Changing Poi Colors Based on Speed and Velocity”