Conductive filament means printable sensors

The 3D printer world has the creation of plastic trinkets pretty much down pat. The next step, obviously, is the creation of multi-material models, whether they be made of two different colors of plastic, or completely different materials entirely. A few folks from the University of Warwick and GKN Aerospace in Bristol, UK have come up with a way of putting electronic sensors directly into 3D printed objects.

These new sensors rely on a conductive filament custom-made for this study. So far, the researchers have created flex sensors, capacitive buttons, and a ‘smart’ mug that can sense how much water is contained within.

To produce their ‘carbomorph’ filament, the researchers stirred regular old carbon black to a sample of polycaprolactone dissolved in a solvent. After shaking well, the mixture was laid out on a piece of glass for an hour resulting in a thin film that could then be rolled into a 3mm filament. While this is a great way of producing small quantities of carbomorph filament, we’re sure a few Hackaday readers can come up with an easier way of rolling their own conductive filament. Send us a link if you’ve figured out a better way.

Tip ‘o the hat to [Evan] for this one

Hacking BodyBugg fitness sensors to get around subscription fee

This arm cuff is a sensor package which logs data whenever you’re wearing it. It records accelerometer data, skin temperature, and galvanic skin response. That data can then be analyzed to arrive at figures like calories burned. But… The company behind the device seems to have included a way to keep the cash flowing. Once you buy it you can read the data off of the device using a Java program they supply. But you can’t erase the data from the device unless you subscribe to their online service. Once it fills up, it’s useless. [Doug] wasn’t happy with this gotcha, so he reverse engineered the technique used to clear the BodyBugg’s memory.

There had been a few previous attempts at reverse engineering the device but that groundwork didn’t really help [Doug] on his quest. He ended up disassembling the Java classes from the original program. This helped him figure out how to initialize communications. Once there he was happy to find that the device will tell you how to use it. If you issue an invalid command it will respond with a list of all valid commands. Everything you need to get up and running can be found in his github repo.

Adding Node.js based sensors to the Parrot AR drone

[Max Ogden] wanted the option to add sensors to his Parrot AR Drone. This a commercially available quadcopter which runs Linux. This makes it rather easy for him to use Node.js to read the sensors from an Arduino board. The use of the Arduino is merely for easy prototyping. It is only needed to bridge the drone’s serial port with a sensor’s delivery method, so just about any microcontroller could be substituted for it.

There are some hardware considerations to take into account. The manufacturer was nice enough to populate a 0.1″ pitch pin socket on the serial port (if only this kind of invitation to mess with hardware was an industry standard). But the device expects 3.3V levels so pick your hardware accordingly. There is one commenter who tried the project for themselves and found that the drone wouldn’t boot up with the Arduino already connect — he had to boot and then complete connections. Troubles aside this makes adding your own sensor payload very simple and you don’t have to wait until landing to get at the data.

Maybe we’ll have to add some shock voltage data reporting to our shockerDrone.

Reading analog sensors with the Raspberry Pi

Adafruit just posted an awesome tutorial on reading analog sensors with the Raspberry Pi. It’s a great walkthrough that can be applied to your next Raspi project as well as any project where you just need one more analog input.

Earlier, the folks over at Adafruit posted a tutorial on using a MCP3008 ADC with the Raspi to directly read analog values using a Raspi. Sometimes, though, you don’t need eight analog inputs and a 12-bit ADC to get a project off the ground. Adafruit’s tutorial for reading analog values without an ADC relies on a single 1μF ceramic capacitor attached between a digital input and ground. By pulling the sensor line high for a millisecond or two, the capacitor charges at different rates depending on the value of the analog sensor.

Yes, it’s just an RC timing circuit but seeing as how the Raspi doesn’t have an analog input, we figure this tutorial could help out a few people.

Lighting controller counts how many people are in a room

[Deekshith Allamaneni] built this controller which will automatically turn the lights in a room on and off. No big deal, right? You can already get a replacement light switch at the home store that will do this for you. But there is one big difference. The commercial solutions we’ve seen simply rely in a motion sensor and a timer. But [Deekshith] found a way to count the number of people that enter a room, turning the lights on when the first person enters and off when the last person leaves.

The video after the break shows a demo of his test rig. At first we just thought that this was only counting how many times an object passes between the sensors. But it can also detect in which direction that object was traveling. Now the system just needs to be scaled up for use in a doorway.

It would be a great addition to the house that doesn’t have any light switches.

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Building an autonomous robot from an Xbox 360 controller

Wow, it’s amazing what [Carl] was able to build using an Xbox 360 control PCB as the base for his robot. His forum posts just touches the surface of the build, but he linked to a PDF file which has the full details.

This build basically attaches sensors and replacement motors to the controller board… and that is it! Some distance sensors are connected to the analog inputs for the left and right trigger. The whiskers use a couple of leaf switches soldered to controller button pads. The motors are geared replacements that use the same connectors as the rumble motors did.

The idea is that the controller is connected to a PC via the wireless radio it has on the PCB. Once the connection is made the PC software can read from all of the sensors and drive the motors accordingly. It would also be really easy to use a single-board solution like the RPi to do away with the need for a remote PC. But this is a fantastic start, and an approach which we had never before considered. See some video of the little guy getting around the room after the break.

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Sensordrone really does make your phone a tricoder

Sensordrone is a sensor-filled wireless dongle for use with a smart phone or other computer-like device. But perhaps this is better explained as the thing that makes your smart phone work exactly as the original Star Trek tricorders did. In one had you have the main unit that displays data, in the other you hold the sensor array which you can wave in front of things to take a reading.

This is really just a Bluetooth module, battery, a handful of sensors, and a breakout header all packaged in a nice case. But seeing it used in the video after the break does make us a little giddy. That breakout header gives you the option of connecting the Sensordrone to RS-232 or I2C devices. The first demonstration is a thermal printer being sent a print job from an Android phone. But the dongle isn’t just a pass-through. It comes with a range of sensors (those three windows in the case) for gas sensing, temperature, humidity, pressure, color sensing, and perhaps a few others.

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