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1  Using Arduino / Project Guidance / Re: Wireless VIdeo Transmission on: July 01, 2014, 08:40:56 pm
So the video is piped right to the glasses, i.e. no digital processing on the video? That will work.

I tried a similar camera and it gave me much trouble. Sometimes it would work and sometimes it would not. It required a lot of fiddling.

Also tried an iPhone to a python program running on a mac. That worked ok, i.e. relatively stable. Hardest part here is dealing with multiple programming environments. Would probably be easier with an Android phone in Java going to a Java server.
2  Topics / Robotics / Re: Basic Robot Platform on: May 17, 2014, 05:14:28 pm
Personally I like this better from Roboshop: http://www.robotshop.com/en/dfrobotshop-rover-tracked-robot-basic-kit.html. I'm not sure its right for middle schoolers, might be to sophisticated.

However, most middle school programs use Lego Mindstorms, Paralax Boebot or VeX. Legos are challenging enough for middle schoolers and you can use different software should they prove more advanced. The advantage of the kits is they get something going. Building from scratch, like buying a chasis w/o motors, can be frustrating for noobs.

And 2k is not much. So its good to put the kids in groups and let them play.

3  Topics / Robotics / Re: Tracking position of an autonomous robot on: May 17, 2014, 05:01:12 pm
This is a pretty hard project. All the dead reckoning methods are useful but only partial solutions.

IR beacons are a common solution, but even they are fairly challenging for beginners. They were used in the MIT media lab and you can buy em from Pololu.

The google car uses LIDAR which is like a 360 degree range finder. In the hobby range, you might try using an ultrasonic range finder or a webcam. The range finder can be coupled with a motor so you can get a range of readings without turning your bot. This should be more than challenging for a noob. After that I'd switch to the webcam (which can't be processed on an arduino), but there are lots of options. Webcams are cheap and provide images with lots of information. The challenge is in processing them.
4  Topics / Robotics / Re: ROV tether code. on: May 17, 2014, 04:37:04 pm
What range does TTL work? Is that just 2 wire Rx & Tx?
5  Community / Products and Services / Re: RFduino: iPhone, Bluetooth 4.0 LE, Arduino Compatible Board! on: March 28, 2013, 06:34:34 pm
The RFduino is loads cheaper than an Arduino with Bluetooth. It contains a Nordic 32 bit ARM Cortex-M0 processor. Any idea how this processor compares with an Arduino UNO or an iPhone performance-wise like for image processing?
6  Using Arduino / Project Guidance / Preamps vs Analog to Digital Converter on: October 03, 2012, 09:43:53 pm
I was reading these threads about seismographs:
http://sydney.edu.au/science/uniserve_science/school/Seismograph/detector/index.html#sept
http://arduino.cc/forum/index.php/topic,56217.0.html.

The stages are: sensor (pendulum, gyroscope, etc) => preamp => analog to digital converter => computer

Why use a preamp as opposed to a 24 bit analog to digital converter like the LTC2400?
7  Using Arduino / Motors, Mechanics, and Power / Re: 5V LiPo - Seems kind of clumsy on: August 24, 2012, 11:12:19 am
I looked a bit more and they have an integrated charger booster: https://www.sparkfun.com/products/11231
It needs a header for connecting to breadboard, but they have taken care of the JST connectors! Micro USB though.

Just ordered it. And a plug for SparkFun USPS shipping. It is only like $4. I hate to spend $11 for UPS for a couple of items.
8  Using Arduino / Motors, Mechanics, and Power / Re: 5V LiPo - Seems kind of clumsy on: August 24, 2012, 10:46:11 am
Good thought. I just added some comments at SparkFun. Stuff like missing connectors slows me up a lot. It's more ordering them then the soldering.
9  Using Arduino / Motors, Mechanics, and Power / 5V LiPo - Seems kind of clumsy on: August 24, 2012, 09:39:22 am
It looks like to power a 5V arduino requires:
LiPo battery with JST connector: https://www.sparkfun.com/products/341
5V DC to DC Step Up: https://www.sparkfun.com/products/8290?
Charger: https://www.sparkfun.com/products/10401

The battery connects to the charger easy enough, connecting the Step Up boards seems very clumsy.
To connect the battery to the Step Up, a JST connector like has to be soldered to the Step Up board: https://www.sparkfun.com/products/9749
To connect the Step Up to the Arduino, requires soldering jumper cables to the Step Up board.

I guess this is no big deal, but thought this was fairly common and soldering would not be required.
10  Topics / Robotics / Re: Need idea for Gripper - Robotic Arm on: August 23, 2012, 10:00:55 pm
Here is cardboard crane and gripper: http://www.kickstarter.com/projects/392540503/cardboard-robot-robotic-arm-and-smart-phone-camera

It is 5' plus, which is kind of crazy for cardboard. I bet a smaller one could lift a bit more.
11  Using Arduino / Motors, Mechanics, and Power / Bot with treads has trouble turning on: August 23, 2012, 09:55:41 pm
Bot has Tamiya Twin motor GearBox Set, L293D and 850 mAh LiPo. This battery: https://www.sparkfun.com/products/341

It seems to go straight ok on the floor or carpet. Turning is a problem, particularly on carpet. If you slow a track down it tends to stall.

The gears seem kind of loose. Is slippage and jamming common? Is it underpowered for turning, particularly when there is good traction? Any ballpark ideas how long before needing a charge and is it okay to run it like 15 minutes straight?
12  Using Arduino / Networking, Protocols, and Devices / Re: 2 Signals + Wifly to iPad on: August 22, 2012, 05:54:08 pm
You should be able to do that on an iPad with its wifi capability. I've used an iPhone to connect to a PC.

I used asyncsocket. Here is an example: https://github.com/twyatt/asyncsocket-example

This is medium complex. Probably should start by writing the iPad server and seeing if you can connect from your PC. You need to be a member of Apple's developer program ($99). Stackoverflow can help with the iPad questions.
13  Community / Gigs and Collaborations / Re: Personal Emergency Transmitter on: August 19, 2012, 10:34:11 pm
Is there free GSM for emergencies or would GSM require a cell phone contract?

Here is a watch that could be programmed for this purpose: http://www.kickstarter.com/projects/597507018/pebble-e-paper-watch-for-iphone-and-android. It requires a smartphone.
14  Using Arduino / Project Guidance / Re: How to get facial recogniction? on: August 19, 2012, 10:16:24 pm
I bet you could use OpenCV to segment a face. Then train a neural network on the faces. This is not an Arduino project.
15  Using Arduino / Project Guidance / Re: VEX and DF RobotShop Rover verse homemade bots on: August 19, 2012, 10:13:05 pm
One big problem I have is not wanting to wait for parts when I have the opportunity to work. Also, my wife does not like me using power tools in the kitchen. But my wife and family were away for the weekend, so the cardboard chasis was largely replaced by HDPE, one battery was replaced by a LiPo battery, and a simple bracket was added for a smartphone. The result is quite suitable for indoor SLAM projects.

It does not compare with the Grasshopper with its 4 wheel independent suspension and large motor. Maybe that will be my next project? I don't want to build from scratch again.
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