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1  Topics / Robotics / Re: egg detector robot on: July 26, 2014, 07:58:14 pm
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.
2  Topics / Robotics / Re: MPU-9150 + L293D + Arduino Mega + Li-Po Battery + Robot, Arduino Gets Stuck! on: July 26, 2014, 03:24:34 pm
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2. try putting additional filtering at the point where the battery connects to the rest of the system, eg 220-470uF [yeah, a big one] and 100nF. See the following page, re "Main Capacitor", and how transient loads cause large voltage transients on the buss. This is due to inductance in the leads from the battery.
http://www.4qdtec.com/pwm-01.html#cap
Yeah, I've already explained it 2 or 3 times. Read the link.

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sensor working fine(SEPARATELY)
l298 working fine(SEPARATELY)

but together they dont.
When all together, does the processor stop working, and stop communicating with the PC? Can you still turn the motor on and off?

I'd also put a 10-22uF cap across the MPU Vcc to gnd pins. Also, the MPU chip operation may be highly sensitive to spaghetti wiring like you end up with when using whiteboards. Item 4 above:
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Also, adding item 4 to the three above, in general with electronics there is no magic bullet. IE, no one "fix" may cause all the problems to go away. Electronics is really always a systems-level problem, and everything has to be done properly. The first thing is always to get rid of the spaghetti wiring lashup, and do it right. This helps reduce noise, ground loops, cross-talk, signal radiation, on and on.
3  Topics / Robotics / Re: Robot project on: July 26, 2014, 02:52:40 pm
Speech recognition is not the most mature technology. Especially in tiny packages such as can go on a robot. However, if you do a google search, you'll find 1,000,000 links on this sort of thing.

A simpler thing to do would be to use PIR detectors, which would help the robot recognize and follow warm moving bodies, and maybe an audio amp to trigger when someone talks. IOW, start simple, then build up from there.

http://www.ebay.com/sch/i.html?_odkw=pir+detector&tpos=unknow&talgo=origal&_osacat=67003&_from=R40&tfrom=270812987833&ttype=price&_trksid=p2045573.m570.l1313.TR12.TRC2.A0.H0.Xpir+sensor&_nkw=pir+sensor&_sacat=67003
4  Topics / Home Automation and Networked Objects / Re: Motion detection behind wall on: July 26, 2014, 02:45:28 pm
http://www.ebay.com/itm/Wireless-Module-Microwave-Doppler-Radar-Motion-Sensor-/130512020245

Sounds like a typical college project to me.
5  Topics / Robotics / Re: MPU-9150 + L293D + Arduino Mega + Li-Po Battery + Robot, Arduino Gets Stuck! on: July 26, 2014, 02:41:51 pm
You need to isolate the problem area. Remove unneeded components, get the thing working, add the removed components back in.

5. disconnect the MPU and get the Arduino <--> motor part working first.

And you obviously did NOT try items 2 and 3 in my first reply.
6  Topics / Robotics / Re: MPU-9150 + L293D + Arduino Mega + Li-Po Battery + Robot, Arduino Gets Stuck! on: July 24, 2014, 08:06:44 pm
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b:That's what is called common ground reference, when all grounds end up to the same point ..
I think common ground reference means something different than [SPSG] single-point star-grounding.  SPSG refers to a specific wiring arrangement, ie geometry, and not voltage reference.

Typically, the grounds in any system are all connected together, so whether you use SPSG or not, or a big mishmash of spaghetti and ground loops, supposedly you will have a "common ground reference". But in reality, there can be all sorts of noise and voltage-shifts on the grounds in the system, and you'll probably never have the same potential at every ground point in the entire system.
7  Topics / Robotics / Re: MPU-9150 + L293D + Arduino Mega + Li-Po Battery + Robot, Arduino Gets Stuck! on: July 24, 2014, 07:25:19 pm
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You mean he should add a large capacitor directly  on the power supply right ?
When you say "single-point", you mean same ground or common reference, correct ?
Not quite. It's all shown in the references I gave.

a. the capacitor goes right at the point where the battery connects to the system, meaning at the "+" below. With the capacitor there, it compensates for the inductance in the battery-wires, and removes the inductive voltage transient.
  
   battery - battery_wires --- + --- controller

b. "single-point" means the ground wires, and power leads for that matter, from all of the subsystems [eg, battery, logic controller, motor controller] are brought to a single-point. So the wiring looks like a "star", or I prefer, an octopus. No ground loops. This way the current distributed to each subsystem goes through its own set of wires, and never goes through the wires of the other subsystems.

Also, adding item 4 to the three above, in general with electronics there is no magic bullet. IE, no one "fix" may cause all the problems to go away. Electronics is really always a systems-level problem, and everything has to be done properly. The first thing is always to get rid of the spaghetti wiring lashup, and do it right. This helps reduce noise, ground loops, cross-talk, signal radiation, on and on.
8  Topics / Robotics / Re: MPU-9150 + L293D + Arduino Mega + Li-Po Battery + Robot, Arduino Gets Stuck! on: July 24, 2014, 06:25:09 pm
This is a very common problem when trying to run both motor and logic controller off a single battery. First, the motors put electrical noise on the controller power buss, and secondly, when the motors start running, they will often pull the battery buss voltage down temporarily, and reset the controller.

1. try using 2 separate power supplies and see if that works.

2. try putting additional filtering at the point where the battery connects to the rest of the system, eg 220-470uF [yeah, a big one] and 100nF. See the following page, re "Main Capacitor", and how transient loads cause large voltage transients on the buss. This is due to inductance in the leads from the battery.
http://www.4qdtec.com/pwm-01.html#cap

3. always use a "single-point" or "star-grounding" configuration. This helps prevent motor current transients from appearing on the controller power lines.
http://electronics.stackexchange.com/questions/24496/how-should-i-organize-this-star-grounding-network
http://www.interferencetechnology.com/designing-electronic-systems-for-emc-grounding-for-the-control-of-emi-3/ (scroll down)
9  Using Arduino / Microcontrollers / Re: SoftwareSerial not working with ATMEGA1284P on: July 21, 2014, 02:50:06 pm
Well, good luck.
10  Using Arduino / Microcontrollers / Re: SoftwareSerial not working with ATMEGA1284P on: July 21, 2014, 01:20:49 pm
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AVR Developers pinout
1. this pinout is not Arduino shield compatible, so possible you do actually have the wrong pins.

2. I, for one, never had ANY luck whatsoever using softserial, and gave up on it totally, although other people swear by it.

3. the mega1284 has 2 hardware UARTs, and I think you'd be much better off using one of those. This is why I went to the 1284 in the first place.

4. your sketch doesn't even use the default UART. I'd try my code on that "first", and then use it to debug the softserial stuff, if you persist with it.
11  Topics / Robotics / Re: Problem driving motors with the adafruit motor shield on: July 19, 2014, 11:37:28 am
correct.

do you think that the batteries may be the problem?
See this thread,
http://forum.arduino.cc/index.php?topic=255068.0
12  Topics / Robotics / Re: L293dne & Tamiya dual motors gear box. on: July 18, 2014, 11:32:16 am
The little 9V bricks will not provide enough energy to run the motors. You want to use something like 6 to 8 AA-cells in series. I always use NiMH rechargeable cells.

Also, 3V is too low. First, the L293 will likely not work correctly at such a low voltage. Read the datasheet. Secondly, you get a voltage drop in these chips on the order of 1.5V or so, since they use bipolar rather than MOSFET technology, so the motor gets a lower voltage than the battery.
13  Topics / Robotics / Re: obstacle avoiding bot with IR SHARP, 2 DC motors and micro servo not working on: July 15, 2014, 01:17:51 pm
With robots, power is always the first issue to look at. With electronics in general, hookup is always the first issue to look at.

Also, since motors and servos tend to generate a LOT of electrical noise, it's usually best to use separate batteries for the electronics and motor sections. Also, you should always have a good deal of filtering at the point where the motor battery connects to the h-bridge Vcc pin, eg a 100nF bypass cap, and 100uf [or higher] electrolytic.
14  Topics / Robotics / Re: obstacle avoiding bot with IR SHARP, 2 DC motors and micro servo not working on: July 14, 2014, 02:47:54 pm
It's a little difficult to tell if every thing is hooked up correctly, so just a couple of suggestions.

1. you should use a better battery for the motors, as those 9V bricks don't last very long, even for the Arduino board. I use series-wired NiMH AA-cells on my robots.

2. you should never power an r/c servo from the Arduino 5V pin, as the voltage regulator won't adequately provide high enough currents, and powering any motors off the regulated 5V will add noise on the microprocessor Vcc.

3. you'd be much better off buying a motor shield, then you can directly connect the servos and motors without a spaghetti wiring mess. Eg,

http://www.adafruit.com/products/81
http://www.ebay.com/itm/L293D-Motor-Shield-Board-Arduino-MEGA-UNO-Duemilanove-Best-Quality-US-SELLER-/181174426234

4. also, when it comes to writing software, you want to always use modular programming techniques, writing everything as functional modules that basically each perform just one function [eg, motor control], for which you have a good start.

5. you want to test the various subsystems in "isolation" before putting the modules together . So make sure the motor control modules run the motors properly, and the sensor read modules output the correct data, etc, first. Then, put them together once you know each works correctly.
15  Topics / Robotics / Re: Can any of you help me pick a robot kit please? on: July 12, 2014, 11:58:37 am
On doing a little more checking, I found the Hobby King prices are good [ie, low], but their shipping costs from CN to the US tend to be on the high side. However, the robot kits they sell are also available from many other vendors. Some have free shipping from CN, but the unit prices are also a little more. Eg,
 http://www.dx.com/s/robot+kits

I also see the smart car has the wheel caster, rather than the ball caster.
http://www.dx.com/p/r0008-multi-function-ultrasonic-robot-car-kits-for-arduino-multicolored-the-third-generation-328158#.U8FzXZRdWGM
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