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1  Using Arduino / General Electronics / Re: robot arm project queries on: July 30, 2014, 07:15:07 pm
Mosfets are on or off based on the level of the gate. But that's not important now.

If you are thinking of using one mosfet/transistor per motor you will only be able to drive the motor in one direction. That is of course not what you want. You need a full bridge for bidirectional control. An L293 is a common answer for this -- it can drive two motors up to 1A each -- but it's not a particularly durable chip.
2  Using Arduino / Interfacing w/ Software on the Computer / Re: How to get output of system() command? on: July 30, 2014, 09:01:02 am
You can use the programming language of your choice to read the system status and send it to an Arduino. The InterfacingWithSoftware page lists examples for just about every language under the sun.
3  Using Arduino / General Electronics / Re: robot arm project queries on: July 30, 2014, 02:08:50 am
That arm contains four motors plus a "searchlight". The nine, TO-style packages on that board you have pictured would be insufficient to form four full bridges.

If you subtract one chip for the searchlight, that would leave eight chips which would more likely be half bridges like the BTS7930.

But to the real question, I doubt these motors consume more than 1A.
4  Using Arduino / Project Guidance / Re: Quadcopter software on: July 29, 2014, 09:51:00 pm
You're looking for the MultiWii code. It's designed to be configurable for a wide array of processors and sensors for a similarly wide array of aircraft/gimbals/etc.
5  Using Arduino / Project Guidance / Re: RC controller stick input bypass on: July 29, 2014, 09:49:11 pm
A 74HC4053 will let you switch three channels, individually, from manual (stick) to Arduino control. So with one digital pin on the Arduino you can switch between the signal from the stick or the signal that your Arduino is creating. A 74HC157 will let you switch four channels, all at the same time, between manual and Arduino control.

The difficulty here is smoothing out the analogWritten PWM (square wave) signal from the Arduino into something smooth enough that your receiver will accept it. I'm going to defer to others on the forum for suggestions on how to do that.
6  Using Arduino / Microcontrollers / Re: Bootloading ATmega-PU Access is denied. on: July 29, 2014, 01:03:06 am
ArduinoISP allows for three status LEDs on pins 7, 8, and 9. For the sake of maintaining your sanity I suggest you add them so you know that ArduinoISP is loaded and your reset disable is working . At least add one to pin 9 which will fade up/down when you have ArduinoISP loaded.
7  Topics / Product Design / Re: PCB printing device on: July 28, 2014, 04:37:28 pm
You'd be better off supporting the much more economical AgIC Print project. If you really need the pick-and-place then try the RetroPopulator or Firepick Delta.

Do I get it right, that AgIC can print only on paper? Firepick looks really good, but I would prefer to have 1 device for all the operations.

If it would help you decide, why not just walk over to the BYU lab that your fellows are developing the Firepick in and ask to try it out?
8  Using Arduino / General Electronics / Re: voltage regulators on: July 27, 2014, 09:48:42 am
Search eBay for "LM2596 module" for an inexpensive buck converter. Price is around $1 per module.
9  Using Arduino / Sensors / Re: IR break beam sensor on: July 27, 2014, 09:42:38 am
Two things with respect to unreliability:

1) Receiver is in bright light / direct sun. This causes it to send lots of spurious signals.
2) The datasheet recommends use of a capacitor and resistor near the receiver to filter out dirty power. I didn't need that myself and was using ~1 meter cables to connect the receivers, but y'know.

Other than that, I dunno. Your results are interesting to say the least.
10  Community / Bar Sport / Re: Name of connectors on SMD modules on: July 27, 2014, 02:24:44 am
I'm pretty sure all of the Chinese board houses (Itead, Seeed, Elecrow) will do the castellation.
11  Topics / Robotics / Re: egg detector robot on: July 27, 2014, 02:10:09 am
I don't know if they still exist, but there was the AvrCam that used a cmos camera, and was able to recognize and track round colored objects like orange balls, etc.
You might be thinking of CMUcam.
12  Using Arduino / Project Guidance / Re: GPS on Sport's Fields - too much error on: July 26, 2014, 07:43:52 pm
The "NavSpark" is a GPS receiver/processor designed for this type of problem. Not a simple project but it can be done reasonably inexpensively, and you can get 10cm level accuracy. Slapping together a rover is still a complex project because accuracy depends so much on getting good GPS signals.

The "Piksi" is another option; a little more expensive but seems to have packaged everything together a bit better.
13  Using Arduino / Sensors / Re: How do I use a KTY 81-220 temperature sensor in arduino? on: July 25, 2014, 11:37:58 am

Since yours is a 2K thermistor you would use it with a 2K resistor; example above shows a 10K resistor.
14  Using Arduino / Project Guidance / Re: IR Microcode/Microdot and Shape Scanner/Reader, and Adjustable Bluetooth ranges. on: July 25, 2014, 11:23:37 am
Example of such a pen:

I can't imagine being able to build something like this without the R&D $$$ that AnalysIR mentioned. A camera, optics, ARM processor, bluetooth, and battery management in something that size? No DIYer could pull that off.
15  Using Arduino / Project Guidance / Re: Multiple BLDC control Circuit with Arduino Micro on: July 25, 2014, 11:10:00 am
Everything looks correct to me.
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