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1  Using Arduino / Microcontrollers / Re: SoftwareSerial not working with ATMEGA1284P on: July 21, 2014, 02:50:06 pm
Well, good luck.
2  Using Arduino / Microcontrollers / Re: SoftwareSerial not working with ATMEGA1284P on: July 21, 2014, 01:20:49 pm
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.
3  Topics / Robotics / Re: Problem driving motors with the adafruit motor shield on: July 19, 2014, 11:37:28 am

do you think that the batteries may be the problem?
See this thread,
4  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.
5  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.
6  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,

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.
7  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,

I also see the smart car has the wheel caster, rather than the ball caster.
8  Topics / Robotics / Re: Can any of you help me pick a robot kit please? on: July 11, 2014, 05:43:46 pm
Problem with the two wheel ones is something has to hold up the end. That is usually a caster. The caster is very small and won't go over carpet or bumps.

Yeah, best to look for a 2WD platform that uses a rotatable wheel rather than a caster. I did look at the pictures of the HK 2WD platform but couldn't tell whether the idler was wheel or caster.
9  Topics / Robotics / Re: Can any of you help me pick a robot kit please? on: July 11, 2014, 03:16:15 pm
Hobby King also has a bunch of nice robot kits.

Despite what steinie mentioned, I've found that 4WD bots tend to have trouble turning on carpet, as the tires tend to bind, and you need to set the motor speed [ie, PWM duty] way up, or else the bot will stall. This is especially a problem with 4WD robots that have higher speed motor gearing and off-road [knobbly] tires.

Also, a big problem with many tracked platforms is the treads tend to come off when turning on carpet.

Also, if the tires are too smooth on 2WD robots, sometimes there is a problem with getting over transitions like the floor strips at doorways, and the metal strips used to hold down the edges of carpets.

I like the design of this robot for a starter kit, but haven't tried it myself, so cannot say about carpet vs hard floors vs transitions. But you get a lot for cheap.

One problem with standard Arduino boards is it's a huge PITN to interface them to r/c servos, but you notice the board that comes with the kit mentioned is specially designed for plugging in servo 3-pin connectors.
10  Using Arduino / Microcontrollers / Re: ATMEGA 1284 - Definative Bootloader Solution.... on: July 11, 2014, 02:57:25 pm
I have a few cheapo ISP programmers and some normal usb/serial type programmers, I am going to have a go at both options this weekend as I have a few 1284's kicking around...

I was looking at this ....

there seems to be so many variants, I just dont know which to go for !!

Thanks for all the replies so far

That's the new update the other guys were talking about. Maniacbug is currently MIA, so Jack has taken over the updating process.

However, FWIW, for the past year and a half, I've been using the maniacbug 1284 optiboot bootloader with no problems, and I've written literally dozens of programs. There is a problem in that the IDE libraries and most 3rd party libraries do not fully support the 1284, so you should read the thread that Bob mentioned and look at Jack's github page to find details if using any libraries.

In regards variants, as Bob mentioned, they each have a pins_arduino.h file that dictates how the "chip" pins are wired to the "header" pins on the different boards, etc, so you choose a variant based upon how you want the headers mapped. Eg, Bob has his Bobuino variant which has a UNO-type header layout, so it's easy to mount standard Arduino shields on his board. The other variants are completely alien to Arduino layouts.

However, note that, in general, the "same" bootloader burned into the chip [ie, optiboot-1284] will be used for all the different board variants, and only the pin mapping will change when you compile a sketch.

while (z--) { snore; }
Ummm, try sleeping on your side.
11  Topics / Robotics / Re: artificial intelligence robot. on: July 10, 2014, 06:58:45 pm
Subsumption architecture, that cr0sh mentioned, is probably the most popular programming scheme for small robots. There are 2 classic books on this by Joe Jones. The first one has much material on both building the hardware and also writing subsumption code [it's all in C], and although a little old it's still the best introductory book, AFAIAC. Things haven't changed a lot since then, in regards small hobbyist robots, except that now you can buy a lot more hardware kits. The 2nd book goes more deeply into software and sensor issues.

The single most important aspect to building a successful robot is to have several different kinds of sensors that complement each other, as single sensors tend to be too unreliable.
12  Using Arduino / Microcontrollers / Re: Set pin13 (XTAL1) as output at 1284P and now can't program or write fuses on: July 08, 2014, 12:30:28 am
. problem is that I uploaded blink sketch without changing ledpin, I left pin 13 which is XTAL1 and since then I can't program nor reflash bootloader anymore.
This doesn't make any sense, because the pin 13 in the blink sketch refers to pin 13 on the Ardunio header, and NOT to chip pin 13.
13  Topics / Robotics / Re: Need help to program a mobile robot on: June 24, 2014, 12:52:52 pm
Except for minor syntax issues, everything you show is almost identical to C language, so moving it to Arduino is trivial. If you don't know C, you need to learn it first. Easy enough to do.

The problem may come in if you are using libraries and functions unique to Matlab, eg whatever the following means. Duh ????

function [qx,qy,v,th,sp]=apf(xc,yc,sf,sl,sr,anf,anl,anr)
14  Topics / Robotics / Re: Need help to program a mobile robot on: June 24, 2014, 12:36:59 pm
I don't know much about this, so cannot answer any questions. However, this is an arcane enough subject that it pays to do some background research as a first step. The technique has been around for a long time,

One problem with this method, like many that are "too" simplistic, is that the robot can get caught in a "local minima" in the field, and loop forever. So, like "everything else" in robotics, you need multiple techniques [and also sensors] that complement each other.
15  Using Arduino / Microcontrollers / Re: Updating the mighty-1284p core on: June 20, 2014, 10:42:15 am
Pico, it's good you've worked out the changes in the SD libraries. I've never used SD, so didn't investigate them previously, in regards my webpage for the 1284.

Also, a lot of people seem to use the maniac bug nRF2401 library, so you might take a look there. It's currently also an unsupported orphan, I should imagine.  Also, since the 1284 has two h.w. UARTs, it's much more useful for radios that use an RS232 I/F, such as XBee and BT. However, I don't know if there are any libraries for those radios.
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