Wednesday, June 20, 2012

What's the difference between Netduino and Arduino?

A friend asked "What's the difference between Arduino and Netduino?", so...

I actually just watched a presentation by Chris Walker (the inventor of the Netduino) a couple of months back.

The Netduino is 100% open source and provides Arduino shield pin compatibility. Like the XDuino and other non-AVR "duino" platforms before, they also provide code compatibility with the Processing libraries used on Arduino.

The Netduino uses the standard .NET Micro Framework SDK. If you outgrow the Netduino, there are a number of high-end boards (200MHz! 8MB!) that you can get for a few hundred dollars. Some even have integrated networking and touchscreens. Any standard .NET Micro Framework code should move between boards by simply re-deploying the application to another board. Plus, their design files are Creative Commons licensed--so you can remix them into your own custom board if you'd like. Lots of commercial customers will do this in high-volume applications.

That said, most microcontroller projects will work nicely on the Netduino.

The Netduino SDK includes added functionality (AnalogInput, PWM) which is Netduino-specific. But it's open-source, so if you wanted to use your code on another platform you could port the behind-the-scenes C code for that to another processor as well.

Now, for a comparison between the Arduino and the Netduino... Arduino is actually a pretty cool board, and the guys who run the project are pretty swell guys. Here are a few points of differentiation:

1. Arduino uses a simplified version of C, so it's pretty low-level. If you're making a really fast-moving blinking lights application using the GPIO pins directly, Arduino is probably a better choice. Netduino uses managed code--which does lots of awesome things for you (and many of them very efficiently)--but there's some additional overhead there.

2. Netduino is 48MHz, 32-bit, has 128KB of Flash (up to 200KB if you remove FileSystem support and such), 60KB of RAM, etc. Arduino is 16MHz, 8-bit, has 32KB of Flash, and a few KB of RAM. They have higher-end versions available with more Flash.

3. Both platforms can be used for simple projects in a pretty straightforward fashion. But as you create larger, more sophisticated programs... As you start wanting to pause your code and step through it to fix a bug in your code... And especially if you like event-based programming, garbage collection, and threading... Well, that's where Netduino becomes the only option.

Both projects (Arduino and Netduino) are helping build the same open source community. They'll also be building some very specific accessories for Netduino and actively promoting and supporting them for Arduino. They'd like to see the whole community grow. But that said, Netduino is a really excellent product. If you want to do cool things with a microcontroller--without all the complication--Netduino is for you.

Tahoe II by Device Solutions (100MHz)

Comparison Table

Tuesday, June 19, 2012

Gearboxes (live and learn)

Some months back, we did an "Introduction to Arduino" then later a complete class teaching our members how to build a robot from scratch. Most of the parts were ordered from Pololu.com, as they offered us a great discount on shipping and then an additional 10%, making it possible for us to create a nearly $60 kit (with shipping) for under $40 per person. The only parts we didn't provide were the Arduino board and batteries (as most people have them already).

The Tamiya gearbox assemblies we ordered were of high quality plastic, metal and even came with lithium grease, but during the class we faced many hardships. You can find great reviews online (these really are good gearbox assemblies at a decent price), but I thought I'd give my 2 cents about why we probably will not be using this model in the future for large classes and give a list of solutions in case you run into the same problems as we did.



1.) Assembly took roughly 90 minutes. It was a great exercise in patience and eye/hand coordination, but I don't think it's something I need to do more than once in a lifetime.

2.) Working with 40 people in a presentation room means when you drop one tiny screw or gear, you're out another 10 minutes crawling around on the floor searching for it.

3.) There are NO EXTRA PARTS. If you lose something, you do not have a working gearbox.

4.) A few people complained that the boxes they received had been opened already (I was the only one with access and didn't tamper with them) and there would be a small grommet or screw missing which impeded the functionality of their Robot.

5.) The bottom of the box is left open, which in most cases is fine, but considering our robots were running around in non-sterile environments, any dust, hair, carpet fibers or dirt from the ground would stick to the grease and create wear on the teeth of the gears over time. We were able to remedy this mostly by applying a few short strips of masking tape to cover the opening. Just make sure the tape doesn't touch the gears.

Now, in the future, we are looking into going with a completely contained gearbox assembly that comes in two separate parts so that they can be spread as far apart or butted up against once another if needed. I've already spoken to someone about getting a few to test with and will post an update with my findings.

Any suggestions?

Monday, June 18, 2012

Progress on the SeaPerch & SeaHawk

Yesterday after flying Quadcopters, Sireesh Adimadhyam and I water-tested the Autonomous Aquatic Vehicle components we've been working on. Today, we will be at Motion Picture Marine, joined by a few others putting some more complete designs together before we have to pack everything up for AUVSI-DARPA Conference in Norfolk, VA. next week.

Today around noon I will be in Google+ Hangouts working on sensors and motors, soldering and uploading code. I'll try to post a blog with documentation, schematics and photos within a couple of weeks. :)



Tuesday, June 12, 2012

Drone pilot finds “river of blood” outside Dallas meatpacking plant

A drone pilot hobbyist in Dallas stumbled across a river of blood coming from a large meatpacking plant. The small drone plane had a camera equipped, which captured images of the red river, suspected of being made of pig blood from the plant.



"I was looking at images after the flight that showed a blood red creek and was thinking, could this really be what I think it is? Can you really do that, surely not?" the pilot tells sUAS News. "Whatever it is, it was flat out gross. Then comes the question of who do I report this to that can find out what it is and where it is coming from."

The pilot, who has asked to remain anonymous, was put in touch with the Texas Environmental Crimes Task Force, who began monitoring the plant for violations. "Any time there is some type of discharge into the Trinity River… especially from an environmental standpoint, this is a real concern," Health and Human Services chief Zach Thompson told sUAS News. "I think they discovered a secondary pipe again is my understanding, so the question is who installed the pipe and why was it there."

The drone hobbyist says he captured the footage from the plant using only a point and shoot camera and a $75 airframe.

-Via Yahoo News, Dallas, TX.

Saturday, June 9, 2012

Inspiration For Those Harvesting Our Future

Today I got to meet a fellow Robot Geek, Joe Beam, who brought his 8 year old daughter along (also enthusiastic about robots). I am seeing an increasing desire in little girls to program and build and hack and get their hands dirty and their minds strong. I can only hope that any parent (especially fathers) who see this in their little girls please please please buy them some LEGO blocks and help them put together their first tool kits. Please do this for the future of our species. Thank you.