You may recall that we gave away a few Seeed Studio Grove Modules a couple weeks back.
The mbed users that we gave the modules to, have kindly shared these libraries - so check them out if you are looking for sensors to use in your next project
, has written up a cookbook page for the Ultrasonic Range Finder.
, has written up a cookbook page for the Grove 3-axis Accelerometer.
has written up a cookbook page for the Grove Real Time Clock
has written up a cookbook page for the Grove Temperature and Humidity Sensor
Well done guys!
We are happy to announce that the collaboration features we've worked so hard on over these past months is now in open beta. This means anyone is welcome to try out the new features. Read on below for instructions on how to try it out. You can also check out the demonstration video below:
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More information about the upcoming features can be found here.
Trying out the beta
Before you try out the new features, please be aware that:
- You will be using a beta which contains major changes compared to the current live mbed.org
- Using programs with the beta is a one-way operation - programs need to be converted to the new format (more info)
- Programs you publish while in betamode will not be visible on the main live site
As a betatester, you are invited to:
- Find and report bugs or errors
- Let us know if anything is confusing or unclear
- Suggest improvements/changes
- Have fun!
To try out the beta, visit http://mbed.org/betamode/ and click 'Enable betamode'.
Please let us know what you think on http://mbed.org/forum/bugs-suggestions or drop us a line at email@example.com.
Electronics distributor SparkFun held their annual Autonomous Vehicle Competition (AVC) last weekend in Boulder, Colorado - and we would like to congratulate for his mbed-powered Rover Robot coming in third place!
Simply put, the objective of the competition is to build an autonomous vehicle that can circumnavigate SparkFun headquarters without any human interference. Whoever does it the fastest, wins! What should also be mentioned is that the course is complicated by traversing through a narrow parking lot of a large building, giant red barrels, a pond, ramps and potholes to name a few.
The 1st placed Team 0x27 managed to navigate the 270m course in just 22.08 sec (officially 2.08sec after a bonus time deduction), with Rover Robot from Team Databus coming in at 37.16sec with an estimated top speed of 20mph.
Michael describes how the autonomous vehicle navigation information is calculated using only three key sensors.
The Robot Rover control system, consisted of three main sensors -
The GPS is a 20Hz Venus638FLPX on Sparkfun breakout board mounted inside with a roof-mounted patch antenna and a ground plane cut from a square of tin that's good for 5-10db signal gain. Serial communication runs at 38400 bps on one of the mbed UARTs. GPS supplies heading information. The robot ignores GPS position information.
Additional heading information comes from an STM L3G4200D gyro on a Pololu minIMU-9, mounted on an aluminum bracket up front. Communication is via I2C at 400kHz. The gyro is sampled at 100Hz.
Wheel encoders on both rear wheels provides accurate distance measurement. Sparkfun QRE1113 sensor boards mounted to the bearing carriers sense the stripes and send signals to a tiny surface mount interface board designed using comparators in a Schmitt-trigger configuration.
Heading is incredibly important in the Sparkfun AVC. An error of only a couple of degrees is the difference between crashing and finishing. The solution on Data Bus feeds lag-compensated gyro and GPS heading data into a Kalman Filter, using the results to update current heading and position with that historical estimate.
Gyro data is the foundation of the heading estimate. It's corrected for bias using heading data from the GPS. Unfortunately the GPS does its own massive amount of filtering and the result is a reduced dynamic range and lag. By saving a second's worth of gyro data and feeding that into a Kalman Filter, a very good estimate is generated. From this, the gyro-based heading is updated. The end result is a heading estimate with high dynamic range and negligible bias.
Meanwhile distance travelled is given by the average distance of the wheel encoders. I calibrated the wheel encoders to Google Earth, my waypoint editor, and found the error falls below 1%. So the robot knows how far it's gone and in what direction, giving a position estimate. The position is estimated in cartesian coordinates which I did for one very good reason: updating the position based on the historical heading estimate.
If we know what direction we were pointing a second ago, we can not only update gyro heading calculations up to present, but, using a rotation matrix, we can update the last second's worth of position estimates up to present very quickly.
success comes after a less fortunate attempt in last years competition. However lessons learnt about the previous year's issues, months of simulations, testing, and analysis ensured a much better result in 2012 for Team Databus. Well done!
Seeed Studio, one of our mbed distributors has kindly sent us some Grove Modules to give-away to mbed users, in return for writing a library and cookbook page for them.
If you want one of the modules, then send an email to firstname.lastname@example.org with 'Seeed Studio' in the subject line telling us which module you would like, and we can get one out to you.
The modules we have are -
Grove - 3-axis Accelerometer - Gone!
Real Time Clock - Gone!
OLED Display - Gone!
Temp and Humidity Sensor - Gone!
Ultrasonic Ranger - Gone!
There is only one of each modules, so first in first served!
EDIT: Modules are all gone now!
Thanks to all of that replied. For those of you that were successful - enjoy the modules, and we look forward to your notebook pages.
If you are interested in future giveaways, join the mbed mailing list
It's has been a busy few months here at mbed, here's a wrap up of a few interesting things that have been happening with mbed -
- Collaboration beta Trials
- Automated Heating Controller using Google Calendar
- NEW NFC Stack for mbed
- UK SMART Grants for Prototype to Product
- Beta Testers Wanted - 3G Mobile Internet
- Live Webinar : Rapid Prototype & Development of USB Connected Devices Using mbed and LPCXpresso
Collaboration beta Trials
We're introducing fully integrated support for code collaboration within the mbed Compiler and Website. Using distributed version control model (DVCS), will allow creation, sharing and collaboration on code repositories and we're looking for a group of developers that are interested in testing these features on a shared library or project. Read more
Automated Heating Controller using Google Calendar
Every now and again there is a home automation hack that seems like it might be something you'd want to implement in your own home. In this project, a developer uses an mbed to control a heater based on events in set in a Google Calendar. Read more
NEW NFC Stack for mbed
Yep that's right, NFC for mbed! Donatien Garnier of AppNearMe has written the µNFC Stack for mbed, allowing developers to interface mbed to the NXP PN532 NFC Controller The stack allows you to build your own NFC-enabled hardware, and interface the AppNearMe framework for Android devices, allowing you to focus on building your feature-rich app that compliments your device. Read more
UK SMART Grants for Prototype to Product
Ashley Evans of the Electronic Technology Networks has contacted us about SMART Grants, and we think they might be of interest to the UK based mbed developers. An mbed user developing a commercial product could be eligible for a funding up to 60% of their R&D cost. Read more
Beta Testers Wanted - 3G Mobile Internet
Join us in testing the new libraries we've created for interfacing the LPC1768 mbed to a Vodafone K3770 USB 3G internet dongle. Beta testing is already under way, and you can find more information and the library on the cookbook page. We've also setup a forum thread for all questions, bug reports and feature suggestions. So if you've been dreaming about a remote internet-connected application, why not begin your mbed + 3G prototype today! Read more
Live Webinar : Rapid Prototype & Development of USB Connected Devices Using mbed and LPCXpresso
Jim Carver (Avnet Electronics) and Paul Boogaards (NXP Semiconductors), two specialists in microcontrollers and embedded development, are going to present a free live webinar on Tuesday June 26th, about rapid prototyping with MCUs including a walk-through of adding USB connectivity to designs using the NXP LPC11U24. Read more
Tell us about your mbed projects...
As you’ve seen, we like to post blogs on mbed.org about interesting projects that mbed users have been working on. We’re always on the lookout for more prototypes and products designed with mbed, and we want to hear from you. So if you are keen to promote your project, share your software libraries or inspire others, then get in touch with us. Our media contacts are always fascinated by mbed projects as well, so you might even get the opportunity to see your story go viral!
You can send us any content you might have including a link to a notebook page, a blog – you can even send us a picture you took with your Smartphone!
Email us at email@example.com with whatever you have and we can help get people reading about your project!
NFC Stack for mbed Build your NFC Prototype!
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Collaboration Features for mbedDistributed Version Control|