The Plant Whisperer

February 11, 2011 by Caleb Kraft 14 Comments

[Jeff], fully acknowledging his inability to keep plants alive, has designed a system to help him out a little bit. The “Plant Whisperer” monitors water levels and notifies him if the plant needs attention. Actually, it notifies him either way. The plant whisperer uses real time text to speech to say one of several pre-programmed things, either proclaiming its happiness or requesting more water. He’s using a parallax propeller for the job as he says it is capable of handling the real time text to speech. We realize this is overkill, but we absolutely love it. The only improvement we would want would be to possibly use a pre-recorded voice for more clarity. You can see a video of it in action after the break.

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Conways’ Wall Of Life And Whiteboard Emporium

January 27, 2011 by Mike Szczys 6 Comments

White board beats chalk board, LED marquee beats white board, and an LED white board trumps them all.

This hybrid lets you draw on the surface with dry erase markers while Conway’s game of life plays out underneath. [Bert] sent us this tip after seeing yesterday’s office marquee. This version is quite similar in appearance but the guts are very different. Inside you’ll find a Parallax SX28 microcontroller doing the heavy lifting. The display is multiplexed but they didn’t go with a common 595 shift register, but a beefier MAX6979 LED driver. We’re not too familiar with this part but it does have a lot of nice features like constant current, and automatic shutdown if serial data stalls for more than 1 second. This is a low-side driver so transistors are used to connect voltage to the rows; the opposite from the setup we looked at yesterday. This was built several years ago and is still working happily even though its permanent home is a breadboard. Source code can be found on this page.

Keyless Entry Via SMS

January 24, 2011 by Mike Szczys 15 Comments

[Billy’s] work got new keys which he didn’t want to carry around with him. Instead he built this system to unlock the door via text message. It is based around a Spinneret Web Server which drives a servo motor. He’s rigged up a pipe hanger to add some leverage to the lock’s knob. We’re surprised that the servo has enough power to do the job here but the video after the break shows there’s really no problem. On the communication side of things [Billy] set up Twilio to wait for text messages from an approved list of senders, then used an HTML form to issue the unlock commands to the webserver.

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Getting Started With The Parallax Propeller

January 4, 2011 by Noah Dunker 17 Comments

The folks at [gadget gangster] have been working on an excellent set of tutorials for getting started with the Propeller chip itself, the open-source Propeller Platform Modules and the Spin programming language that’s used to control things. All of the basics and a growing selection of more advanced topics are covered in gorgeous detail, with most of the tutorials containing helpful photographs and screen shots, source code listings and video walk-throughs to help you understand what the authors are talking about.

Parallax is not new to the microcontroller game. Almost two decades ago, their BASIC Stamp embedded microcontroller was the springboard for many tinkerers. The Parallax Propeller is an easy-to-use microcontroller that’s been gaining popularity for a while now. Several Propeller support modules have hit the market recently, providing power supply and interface functions to the Propeller similar to how the popular Arduino platform interfaces with AVR microcontrollers.

Multiple Core Propeller Speeds Up Display Addressing

October 21, 2010 by Mike Szczys 22 Comments

If you ever wondered what an eight-core Propeller processor can do for you, [Tom] found one answer. He’s using the multiple cores to individually address serial displays. He has six display modules, and each of them incorporate six 8×8 LED modules. This makes for a total of 2304 LEDs, and since they’re addressed by cascading serial data, that means 2304 bytes pushed to the display. You’re going to suffer from quite a bit of slow-down if you choose that communication method.

This is where multiple-cores come in handy. Instead of cascading data between the six modules, he assigned a different core to each. Now he can concurrently address the six displays, reducing his serial data from 2304 bits per frame down to 384 bits per frame. As you can see in the video after the break, updating the display six times as fast as before yields fantastic results.

Now what if you’re using a processor that has forty of these multi-core Propeller chips?

This does make us wonder, can’t the same thing be done on a single-core processor? An eight-bit device takes one cycle to set all eight bits on a single port. So why not just connect the six serial connections on six bits of the same port? Weigh in with your thoughts in the comments.

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Homemade Music Player

October 17, 2010 by Jakob Griffith 20 Comments

Sadly, this pocket mp3 wav player doesn’t come close to the capabilities of even an iPod generation 1 yet, but you have to give [Owen] props for making it in less than 24 hours. The system consists of a Propeller MCU (cleverly wired to be swappable with “shields” similar to Arduino systems), SD card for song storage, and an LM386 for audio. While the setup is a little dull, and only plays through songs non stop with no controls whatsoever, it certainly is a good start in the right direction for a cheap and simple portable music player. Of course some planned changes are in the works, include an accelerometer (gesture based controls?), etched PCB, docking station, and a case. We’re surprised there is no form of screen planned, considering Owen appears to have a rather good handle on touch interfaces; perhaps he’s waiting for revision 3.

Turtles All The Way Down, 40 Propeller MCU Skyscraper

October 8, 2010 by Jakob Griffith 29 Comments

Why bother interconnecting 40 Propeller microcontrollers one on top of the other? For the power that comes from parallel processing of course! [Humanoido] put the setup together for a total of 1280 ports, 640 counters, and more all running at 6.4 billion instructions per second for the low low price of 300-500$ by our count. The “skyscraper” even comes complete with software and schematics, promising developers the ability to expand or adapt for any venture. Why would we need such a setup in the first place? For any of the following: vision tracking/modification, artificial intelligence, advanced robotic control, or more.

Related: [Humanoido] loves putting MCUs together, check out one of his other creations the Basic Stamp supercomputer.

[Thanks Logan996]