DIY Propeller-based ECG

August 3, 2011 by Mike Nathan 18 Comments

propeller_ecg

[Ray] likes to build all sorts of Propeller-based projects, but one of the more interesting items we came across was this DIY ECG. While we have covered other DIY electrocardiograms before, he left the breadboard behind and put together a nicely done PCB for his build.

The ECGs design should be pretty familiar to anyone that has seen our ECG coverage in the past. The user places his thumbs on the large built-in pads, which allow the circuit to sense the electrical signals produced by heart’s contractions. These small electrical impulses are then amplified using an AD627 instrument amplifier before being further amplified via a dual op-amp.

The amplified signal is filtered and then fed into the Propeller’s ADC, which displays the user’s heart rhythms via an LED. The data can also be fed into a computer via an optoisolated serial connection.

[Ray] lays out a litany of warnings and precautions that should be followed before downloading his schematics and firmware. We have to echo those warnings, as it doesn’t take a large well-placed shock to disrupt the heart.

Robotic Gardener Takes Its Cue From Bomb Disposal Bots

August 1, 2011 by Brian Benchoff 4 Comments

[Dave] posted some pictures and videos of his ‘Nuntius’ robot on the Propeller forums. From the pictures it’s an impressive build, but to really appreciate [Dave]’s skill, check out the Youtube demo.

The controller is a Propeller protoboard with bits of angle aluminum fastened together. Pots are positioned at the joints of the remote’s arm so the robot’s arm can mirror the shape of the remote. We usually see Armatron bots controlled via computer, or in the rare case of human control, a mouse. [Dave]’s build just might be one of the first remote manipulator builds we’ve seen on Hack A Day.

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Propeller-based Robot With Basic Object Avoidance

July 6, 2011 by Mike Nathan 6 Comments

propeller_development_robot

The Parallax Propeller is a pretty powerful MCU as [Dino] recently discovered in his latest Hack a Week installment. He wanted to build a simple robotics platform that he could use for testing out various sensors, and he figured he might as well learn about a different type of micro controller in the process.

He pieced together his robot using a pair of old Roomba motors he had sitting around, mounting them on a standard RadioShack project box. A Propeller MSR1 control board runs the show, and a Propeller PING sensor is used to get an idea of what the robot’s surroundings look like. He is an admitted newbie when it comes to using Propeller micro controllers, but [Dino] was able to give his robot some rudimentary object avoidance abilities fairly easily. A few small bugs aside, he had the robot up and running in short order, a testament to how easy it is to work with the Propeller platform.

Stick around to see a brief video covering the robot’s construction we have embedded below.

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Automatic Espresso Loader For Those Late Night Hack Sessions

June 7, 2011 by Jeremy Cook 10 Comments

For [Roy’s] graduate electronics class, he decided to make something that many in and out of the hacking world would certainly love, an automatic espresso loader. One can choose from three flavors available. In order to accomplish this, a Parralax Propeller board is used to control three servos that regulate the amount of coffee dispensed, chosen by a handy LCD HMI (human machine interface).

After the coffee is dispensed, the chute swings out of the way. A modified inkjet cartridge carrier (from a dead printer) is then used to compact the beans. Check out the video of this machine in action after the break. Continue reading “Automatic Espresso Loader For Those Late Night Hack Sessions” →

Hacking Automated Hand Sanitizers With Ben Heck

April 5, 2011 by Mike Nathan 9 Comments

benheck_sanitizer

If you have visited a hospital any time recently, you probably noticed quite a few automated hand sanitizer dispensers scattered throughout the hallways and in each patient’s room. Since hospital-acquired infections are a growing problem, there has been a push for all personnel to use these hand sanitizers regularly to lessen the likelihood of spreading disease.

In the most recent episode of his web show, [Ben Heck] took on the challenge of hacking one of these dispensers to use motion sensors in order to sense when hospital personnel are near, as well as to remind them that they should sanitize their hands on the way out.

He disassembled the dispenser to see how it operated, then worked on replacing the IR sensor pair with a set of motion detectors. He hooked the motion sensors to a Propeller board, which uses a separate add-on board for keeping time. Once the motion sensors are triggered, the passer-by is given a window of time before the machine notifies them to kindly sanitize their hands. All movements and sanitizer dispensing events are logged to an SD card connected to the controller, which can be reviewed to ensure policy compliance.

If you have about 20 minutes to spare it’s worth checking out, and if you are interested in more hand washing tech, check out this DIY hand dryer we featured a while back.

Propeller Lamp

March 30, 2011 by Kevin Dady 16 Comments

Wanting to replace a power hungry halogen lamp in the living room, [Jason Dorie] went out to design a Remote Controlled, Dimmable Led Lamp (pictures). The body of the lamp is a pretty interesting idea, sporting a couple waste baskets with a translucent HDPE skin as the lampshade and a PVC column for structure.

The column is wrapped in a spiral of 16 foot long led strips , and are wired so they can be controlled in groups. Light output is (estimated) at about the same as a 100-150 watt incandescent while only consuming 24 watts.

The lamp is controlled via a universal remote and features a TLC5940 driven by a Propeller, all sitting on a CNC machined PCB. With that much horsepower under a lamp you can expect that it will not just simply dim in and out, so join us after the break for a video to see how to turn on a lamp with style.

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Propeller-Android Communications Using Debug Mode

March 29, 2011 by Mike Szczys 17 Comments

Here’s a new way to connect an Android phone and a Propeller microcontroller. It’s called the PropBridge and uses a very simple circuit with a voltage regulator, a couple of transistors, and a few resistors. The trick to this method lies in creative use of software features that already exist on Android hardware, the Android Debug Bridge (ADB). The ADB was added with development in mind, but since it provides low-level control of certain parts of these devices it was just waiting to be incorporated into a hack.

The Propeller itself uses firmware to make Android think it is one of two different externally connected hardware devices. It can act like a PC running the ADB client or it can mimic a TCP connection. There’s still plenty of room on the uC to add your own firmware, and the majority of the I/O pins are unneeded for the basic connection. Check out the video after the break for a quick overview of the system.

If you need a little help with Android programming before you’re able to use this in your own projects, check out our Android development series.

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