PDA

View Full Version : [Project] RoughBodhi



bodhibuilder
05-20-2009, 08:30 AM
Hello everyone,

After a long time of learning and working on my project, I have finally completed my first robotic creation - RoughBodhi! (since it must have a name) And I would like to share it with you, the community, who has given me a lot of help for which I am thankful.

Since I am neither an engineer nor a programmer by profession, I had much to learn. I used books (something like “electronics for dummies”), forum advice (i.e the ssc32 C# programming guide - Thanks adrenalynn), and trial and error (lesson learnt: if its stupid and it works – it aint stupid).

My goal was to create a rover with a robotic arm that would be able to cruise and grab things as I please. I thought this would be a good way to start my robotics learning.

I used:
- 2 continuous rotation servos for the drive system
- 5 different servos for the mech arm
- ssc32 board for control over all. Connected to ‘the brains’.
- 4 rechargeable energizer batteries for power
- Acer One laptop for ‘the brains’ (running a C# program) and vision (built in camera)
- Mecano, lego, and home depot parts to form the RoughBodhi.

http://forums.trossenrobotics.com/attachment.php?attachmentid=1324&stc=1&thumb=1&d=1242825341 (http://forums.trossenrobotics.com/attachment.php?attachmentid=1324&d=1242825341)

I installed a remote login software on the Acer One laptop and mounted it on the rover. As a result, I can now access the laptop from anywhere with internet, enabling me to see what the laptop/robot sees, and to run my robot control program, which enables full control over the rover’s movement, and the robotic arm’s operation.

here is an accelerated video of RoughBodhi's moves:
YouTube - RoughBodhi

Alex
05-20-2009, 08:52 AM
holy crap bodhibuilder! That's mighty impressive work for a first shot at robotics:D

Congrats! +rep

darkback2
05-20-2009, 12:37 PM
Hey,

Sweet bot...I like the levered segments in the arm! Please post larger pics though...I would like to really get a detailed view...

DB

bodhibuilder
05-22-2009, 09:41 PM
Thanks Alex and darkback2, i appreciate it!!
I'll take a few more detailed pictures of the arm and the bot soon. I decided to go with the levered segments to reduce presure on the servos, and of course to be able to control the leverage.

bodhibuilder
05-25-2009, 05:49 PM
Hey guys,

so i finally got around to taking some closer pictures of my robot

i attached a foto of the arm. a photo of the bot from behind where you can see the wheeled setup with 2 continuous rotation servos on the bottom. and a couple of other ones.

1325

1326

1327

1328

now that i figured out how to control servos using the ssc32, i want to advance to working with sensors. does anyone know if there is a way to attach and get input from sensors using the ssc32??

nagmier
05-25-2009, 07:21 PM
you are going to need another device to take sensor input like an arduino board, PIC or one of a thousand others and I'll leave it to someone with more experience as to which as I have no experience.

Adrenalynn
05-25-2009, 08:28 PM
Sorta. The SSC32 has a couple inputs, but they're only 8bit resolution.

bodhibuilder
05-26-2009, 10:43 AM
And 8bit resolution is bad? how much more inferior is it than.. regular?

would you sugest to get another board then, such as The PhidgetInterfaceKit 0/16/16?

Adrenalynn
05-26-2009, 10:47 AM
Yes, you need another input board. I refuse to comment re: the Phidgets. My opinion of it differs from some other folks opinions... I wouldn't buy one personally, except for paper-weighting, door-stopping, and skeet-targeting. [Ok, it's note quite _that_ much hate. Just an over-reaction to the responses I'll get for hating on the Phidgets]

8 bit = 256 10bit = 1024

bodhibuilder
05-26-2009, 11:10 AM
haha, thats a pretty expensive paper weight... ok, so what would be a better option than the phidgets in your opinion? supposing i want to have an i/o board that is able to connect to my computer.

i still didnt get why 8bit is bad...

Adrenalynn
05-26-2009, 11:27 AM
Let's say you're trying to detect a distance of 1mm to 1000mm (1m)

At 8bits, our max theoretical resolution is 1000/256 ~= 4mm
At 10 bits, our max theoretical resolution is ~= 1mm

So, if there's a child laying on the floor, would you rather embed your robot into the kid 1mm or 4mm? Even worse [;)] would you rather embed your robot into the wall 1mm or 4mm?

Just an illustrative example, but I'm sure you get the point. Having 4x the resolution on a sensor is generally pretty critical...

I would expect any I/O board to be able to connect to your computer, that's kinda the definition right? Input/Output?

How many channels do you need, analog and digital?

bodhibuilder
05-26-2009, 02:48 PM
this is very good information. you should know that i am not anything close to a specialist in electronics so i'm finding out for the firsty time about this whole 8bit stuff. but i now understand that the differance amounts to 4 times less precision if the ssc32 is used.

as i am also new to the i/o stuff: suppose i want to have about 4 sensors, digital (most of them are, especially the ones sold around here, right?) which is the simplest i/o board that would i have to get to receive the signal, and send that information to the computer?

p.s - do you know where there is any information about how to use the ssc32 with sensors - perhaps i can start there to figure out how to use sensors.

Adrenalynn
05-26-2009, 04:04 PM
There isn't any that I've found (information related to that) other than what's in the manual.

Actually, most of the sensors I've seen used around these parts are analog. You still need to be more specific.

trevben1
05-26-2009, 05:39 PM
Nice bot! I'm very curious about your opinions on I/0 boards aswell. For general analog input use what would you say the top 3 boards are? Say if you needed less than 10 inputs.

bodhibuilder
05-27-2009, 10:13 AM
Oh yea! most sensors seem to be analog.

ok, so suppose i wanted to connect about 4 to 10 analog servos from the trossen shop, such as a light sensor, a sonar, etc. which board would you recommend?

(p.s - thanks treyben1!)

Adrenalynn
05-27-2009, 10:40 AM
Ten's an odd number (even though it's even) and you're gonna pay for that. Four puts you in the realm of the Arduino or other ATMega168/328 clone. 8 brings you to the Sanguino-class. 14 to the Arduino Mega. 16 you start paying money for. The Axon, or my current favorite - the 84 channel USB servo controller, which actually gives you up to 36 channels of 10bit A/D. It's a steal for that, imho. http://www.trossenrobotics.com/store/p/5891-84-Channel-USB-Servo-Controller.aspx

Those will probably be the easiest to code to. There's a tremendous wealth of info out there on the Arduinos, and John's done a good job of library development for the Axon.

Make no mistake - there is no plug-and-play solution. You're writing code to support any of these.

bodhibuilder
05-27-2009, 11:14 AM
thats somegood info. i wasnt looking for a plug an play solution and writing code should be interesting. as long as there are examples, documentation and instructions, i should manage.

my other thought / question was... is it possible to connect a motor (lynxmotion GHM-02 to be pecific) to the output of any of these boards to simply be able to control weather it spins or not (to switch that motor on or off by command from my computer using some board)?

i hope these questions dont seem too dumb, but being a beginner in all this, your knowledge is much apreciated!

gaurav.p
07-18-2009, 01:20 AM
awesome mahn way to go