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Author Topic: So many questions...  (Read 5935 times)

fad0

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So many questions...
« on: October 27, 2015, 05:00:15 AM »
I live in Malaysia.  Robot parts are hard to get here and many companies wont ship to Malaysia.  I'm going to the US for Thanksgiving and want to order a bunch of robotics stuff so I can pick it up and bring it back here to play with.  I am seeking recommendations for things to get.  I want a rolling robot that can see, hear, give vocal responses, and possibly have a hand or two.  I have ordered a couple of Pixy's.  I plan to use EasyVR for vocal recognition.  For vocal response, I have used a SD card reader and piped it through DAC on the Arduino Due, but I'm also thinking of just getting an addressable audio player with lots of memory to offload the tasks from the uP. 

My biggest problem I have yet to solve is figuring out how to get the robot to know exactly were it is in the house.  I tried using the GY-80 compass, but at least one of my walls generates a magnetic field and causes the robot to go way off course.  The Pixy, with multi-colored markers in various locations, is what I am thinking right now.  Using quadrature feedback will help, but if the robot collides with an undetected obstacle, the heading vector will change with no way to know unless there are some quadrature free wheels that provide the feedback.

To ramble on, to get my current robot to play music from a SD card reader and feed it to the DAC on the Due, it took me a couple of days to understand how to schedule Audio.write command so it didn't clash with
sonar ping/echo.  Once they collided, the music would become choppy and go into oscillation.  I figured it out, but scheduling tasks with a single processor can be challenging.  Duane recommended Propeller, so I am seriously considering moving over to that.  But 5Mhz seems slow...

So, here are my questions: (and different opinions are very welcome)

1) What Propeller board should I use?
2) The Arlo looks pretty sturdy...maybe a little more expensive than my wife would like...should I drop the cash and get it or should I start with something simpler like the Rover 5?  Any other bodies I should look at?
3) I haven't used quadrature encoded motors, but I expect them to be straight forward to use.  Do you agree?
4) How do I keep my robot oriented in the house?  Or rather, how do you do it?
5) I probably need a power board and motor board.  Recommendations?
6) Recommendations for robotic arms/grabber that could be mounted on something like the Arlo.

I'll leave it at that for now...

Thanks.

deshipu

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Re: So many questions...
« Reply #1 on: October 27, 2015, 06:22:58 AM »
Hi, welcome.

I can't answer all your questions, but I can try to at least tell you what I know.

First of all, the stuff sold in USA is often way overpriced, and you can buy the same or equivalent things at ebay or aliexpress directly from China, where they are manufactured anyways. You have to know what you are looking for, though.

Navigation is a very difficult subject, and there are no universal solutions there. I think the simplest and most robust way is to just have a webcam at the ceiling and a marker on the robot, but of course that has its own drawbacks. If you plan to do visual processing, I'd recommend you to get a computer, not a microcontroller -- something like the beaglebone green, or even raspberry pi. Microcontrollers simply don't have enough processing power, and will require you to get special hardware. With beaglebone you already have the audio problems solved, and you can use a cheap webcam.

Grippers are another difficult subject, and they are projects on their own. I own a MeArm, which is a very basic and relatively cheap robotic arm, but I didn't get to programming it yet, so can't really tell you much about it. However, prepare for it being weak and inaccurate, and still not that cheap.

What do you want your robot to do exactly? Perhaps you don't need full navigation and proper gripper, but could do with some simpler and cheaper solutions?

fad0

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Re: So many questions...
« Reply #2 on: October 27, 2015, 07:36:10 AM »
What do you want your robot to do exactly? Perhaps you don't need full navigation and proper gripper, but could do with some simpler and cheaper solutions?

My wife wants me to build a robot that will go around the edges of the room and sweep up the dust that collects there.  But I don't need a talking robot with an arm for that...

I want to build a robot that knows where it is in the house, and will go to the room I verbally tell it to go to.  It could then pick up something and bring it back to me.  The commands would be something like:  Gallagher (that's his name), room kitchen, object ball, fetch. 

I think the Pixy and EasyVR will handle the complicated stuff.  If I have color coded markers around the house, the Pixy should allow the robot to know where it is, find the object it is looking for, and find me (if I'm color coded too).  Grabbing the object, as you said, is probably more complex than I am thinking...because I haven't thought about it :).

-Dirk

Tor

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Re: So many questions...
« Reply #3 on: October 27, 2015, 07:53:43 AM »
Duane recommended Propeller, so I am seriously considering moving over to that.  But 5Mhz seems slow..
It doesn't run at 5MHz, it's just the crystal that is 5MHz. With a 5MHz crystal the Propeller runs at 80MHz. You can use a 6MHz crystal and run it faster, if  you wish. The propeller has 8 32-bit cores, called 'cogs', with a small bit of memory for each cog and a shared 32KB with slotted access from each cog (that's why it's called a Propeller I guess.. the hub turns around and around and as it passes each cog that cog can read or write data). The Propeller is incredibly flexible and easy to use. See e.g. http://smarthome.jigsy.com/propeller

The Propeller is one of those items which you can't buy cheaper from China.. as it's a US product, not made in China.  It's often easiest to start with a pre-made board, to figure things out, e.g. a QuickStart board (now at a bit above $30 I think). But it's also easy to breadboard a DIP chip and get it to work.


craighissett

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Re: So many questions...
« Reply #4 on: October 27, 2015, 08:15:36 AM »
Duane recommended Propeller, so I am seriously considering moving over to that.  But 5Mhz seems slow..
It doesn't run at 5MHz, it's just the crystal that is 5MHz. With a 5MHz crystal the Propeller runs at 80MHz. You can use a 6MHz crystal and run it faster, if  you wish. The propeller has 8 32-bit cores, called 'cogs', with a small bit of memory for each cog and a shared 32KB with slotted access from each cog (that's why it's called a Propeller I guess.. the hub turns around and around and as it passes each cog that cog can read or write data). The Propeller is incredibly flexible and easy to use. See e.g. http://smarthome.jigsy.com/propeller

The Propeller is one of those items which you can't buy cheaper from China.. as it's a US product, not made in China.  It's often easiest to start with a pre-made board, to figure things out, e.g. a QuickStart board (now at a bit above $30 I think). But it's also easy to breadboard a DIP chip and get it to work.

Thanks for that Tor - I'm really interested in having a look at the Propeller chips now!

deshipu

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Re: So many questions...
« Reply #5 on: October 27, 2015, 10:12:29 AM »
My wife wants me to build a robot that will go around the edges of the room and sweep up the dust that collects there.  But I don't need a talking robot with an arm for that...
I think this is an excellent starting point -- a well-defined task which you could use to gain experience before you go to the more ambitious ones.

Duane Degn

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Re: So many questions...
« Reply #6 on: October 30, 2015, 06:25:30 PM »
It looks like Tor cleared up the confusion about the speed of the Propeller. As Tor mentioned all 8 processors of the Propeller generally runs at 80MHz (when in use, when cogs are not in use the go into a very low power sleep state). The Propeller is also commonly used with 6MHz crystals and 6.25MHz crystals for clock speeds of 96MHz and 100MHz.

I have several of the QuickStart boards mentioned by Tor but I think the Propeller Project Board is a better deal. The Project Board costs about $25.

My wife wants me to build a robot that will go around the edges of the room and sweep up the dust that collects there. 

A lot of the Roombas are very hackable. They have come with a serial port and can be controlled from a microcontroller. Here's a link to my remote controlled Roomba. I didn't have a wireless controller at the time so I used a second Propeller with a wired PlayStation 2 controller and a pair of Nordic nRF24L01+ modules to control the Roomba. I could turn on the various brushes and motors with buttons on the controller and steer the Roomba using a joystick. This was a surprisingly easy project.

You might want to look around for a Roomba to use as a starting point for you cleaning robot.

Where in the US do you plan to travel?

fad0

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Re: So many questions...
« Reply #7 on: November 02, 2015, 09:17:30 AM »
Ahh, I see.  the Propeller must have an on die PLL.  That's cool.  8 processors running at 80Mhz.  Thanks for pointing that out Tor. 

I'm definitely going to pick up one of the Parallax Propellor boards and start playing with it.  I already downloaded SimpleIDE and was looking at the tutorials to get a feel for how to parse the jobs out to the different processors.

Yes, Roomba would be a good starting point...but I'm not too excited about that project yet...
I'm focused on my Pixy, EasyVR integration.  I got the Pixy working.  Now need to get the EasyVR, but I've read that I will have to buy the Software to do the custom commands from the chip design company, and the download cable is hard to get...though it looks really easy to make.

I will be in Bellingham, Washington from Nov 20 - Dec 2nd. 


Duane Degn

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Re: So many questions...
« Reply #8 on: November 03, 2015, 11:17:51 PM »
Now need to get the EasyVR, but I've read that I will have to buy the Software to do the custom commands from the chip design company, and the download cable is hard to get...though it looks really easy to make.

The EasyVR software is a free download. The software isn't absolutely required for custom commands but the software makes the process much easier.

I'm not sure what you mean by the "download cable". If you can connect the EasyVR to a microcontroller and the microcontroller can support two serial lines, then you can use a bridge program to establish PC to EasyVR communication even if you can't connect the EasyVR directly to the PC.

I'm sure I can help you with the EasyVR when you're ready to use it.

fad0

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Re: So many questions...
« Reply #9 on: November 04, 2015, 11:13:24 AM »
First, thank you to everyone.  I keep re-reading everyone's replies and getting more info.  It takes me a while to absorb information...

Deshipu - I am researching the BeagleBone.  And there appears to be a lot of open source visual recognition software available.  But I'm not sure how deep I want to go.  I'm surprised robotics is not more plug and play these days...

Duane - I'll let you know when I get the EasyVR...  I'm not too keen on the Propellor Project Board.  Last time I tried to solder a circuit using that kind of matrix it was a mess and I ended up etching a custom board instead.  It seems like the Activity board will work well, and I like that it has mini SD reader AND audio out jacks.  I'm assuming their signals come from a D/A somewhere on the board or straight off the Propeller.

...I have another question.  My Pixy seems to be flakey and emotionally unstable, especially integrated onto the BOE bot.  I believe it is a power issue.  I've already experienced erratic behavior with my BOE which ended up to be power related so i bought two "UltraFire" 3000mAh 3.7V Li-ion batteries and that solved the problem.  However, with the Pixy and the pan/tilt servos added, I believe I am seeing power-on-reset or brownout problems.  It could just be a capacitance issue.  I think I will put some big caps on the regulated supply and see if that helps.  In the mean time, does anyone have any advice on power management?

Thanks,

Dirk 

deshipu

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Re: So many questions...
« Reply #10 on: November 04, 2015, 05:16:11 PM »
For a more plug-and-play approach, try looking at ROS -- Robot Operating System. It has a lot of ready work already done in form of various plugins.

deshipu

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Re: So many questions...
« Reply #11 on: November 17, 2015, 06:47:43 AM »
Hey, this looks like what you've been after? http://www.updroid.com/

fad0

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Re: So many questions...
« Reply #12 on: November 27, 2015, 12:22:20 AM »
That's pretty cool.  Thanks Desh.

I just got a Beaglebone Black and am messing around with OpenCV, which comes pre-installed.  I can't get the HDMI to work, and I'm having problems updating the kernel.  But I'll figure it out eventually. :)

 

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