Author Topic: TSA (Read 11402 times)

gamefreak · « **on:** January 11, 2008, 05:54:41 PM »

Hey, has anyone here ever head of the Technology Student Associciation? Im thinking for this year to do something robotics related for the Electronic and Experimentation event(basically build anything and write a paper about it), last year I did that RFID door lock which got me to nationals(where i was instantly blown out of the water by thing such as automatic dog feeders). Any think that a photovore or something would be a good entry?

airman00 · « **Reply #1 on:** January 12, 2008, 07:54:04 PM »

interesting

is there a website or something , i might do this

Kohanbash · « **Reply #2 on:** January 12, 2008, 08:24:54 PM »

I think that a standard photovore is to basic/old to make it to nationals. You need to come up with a unique idea if you want to win nationals.

gamefreak · « **Reply #3 on:** January 13, 2008, 12:15:07 PM »

hmm, last year at state I did an RFID door, the other entry(yes only two entrys) was also a door, but it had a button which turned on a light.

I could attempt a robot arm, would make this way more expensive, but would be better.

and heres the web link: http://www.tsaweb.org/

airman00 · « **Reply #4 on:** January 13, 2008, 12:18:01 PM »

whats the website for this?

gamefreak · « **Reply #5 on:** January 13, 2008, 12:28:19 PM »

my above post

I do wonder if the 50 $ robot is capable of a reliable arm, maybe just a preprogrammed, pick up blocks, and move them around.

airman00 · « **Reply #6 on:** January 13, 2008, 12:29:45 PM »

Quote from: gamefreak on January 13, 2008, 12:28:19 PM

my above post

LOL

i scrolled down too fast

thx

and what do you mean capable of an arm?

gamefreak · « **Reply #7 on:** January 13, 2008, 12:38:20 PM »

capable of driving an arm, it probably is but my own incompetance will lead to me breaking and or exploding it.

I see in admins card playing robot he has an actual DC motor driving the rotation, I just so happen to have a Stepping motor with 5 wires, I beleive that means it has 4 steps, and on the motor it says 7.5 degrees with 100 ohms, So I assume if I get a bevel gear then I could have rotation in my arm, and I would drive the motor with some transistor(probably better to get the motor driving kind).

Admin · « **Reply #8 on:** January 13, 2008, 12:39:07 PM »

I am currently using the electronics from the $50 Robot to control this robot arm:
http://www.societyofrobots.com/robot_ERP.shtml

gamefreak · « **Reply #9 on:** January 13, 2008, 12:43:15 PM »

lol, Admin you need to consolidate these pages, I have three pages relating to robot arms, each one from this site. On my 50 $ bot I added 3 more D port plugins, which brings me to 8, so if 4 need to drive my stepper motor, that leads me to a total possible 5 DOF(without a gripper), which for some reason I think would be too complicated for a first arm, making me want to do a 3 DOF with a gripper, hopefully wood wont be too heavy for my arm since its the only thing that I have an unlimited amount of for free, yay for TSA sponsers who are also drafting a woods teachers.

Now I dont think I'll need encoders(except maybe the stepper motor) since the servos are already semi-precisly controllable. But for the stepper do i need a special controller? could I simply turn on the correct transistor for the next step or do i need to find a chip that will work?

Admin · « **Reply #10 on:** January 13, 2008, 01:35:17 PM »

Quote

could I simply turn on the correct transistor for the next step

yeap

although I recommend getting a stepper driver. the better ones just have just two control pins to use so you don't have to waste your mcu pins.

gamefreak · « **Reply #11 on:** January 13, 2008, 01:50:24 PM »

Well im not to worried about wasting pins, 4 got to the stepper motor(the fifth i beleive is on the on/off led from the tutorials), two go to the arm, and one goes to the gripper, which would hopefully by just a claw that opens and closes to grab an I-hook on the blocks....

Laying around in front of my i have: a HS-635HB(says it has high-torque), an HS-311,a parallax standard servo(i beleive it is an hs-311), and a 12 volt bi-polar stepper motor, so I beleive i have my motors covered, I have a 7.2 volt NiCD 2000 MaH pack, a 7.2 volt NiCD 1500 MaH pack, and im going to order a 6 volt battery from mouser. Which would then cover my power needs(can i wire a 1500 MaH in series with a 2000 MaH?). which then leaves me design and construction. Although I need a way for my servos to get 6 and my stepper 12.....

airman00 · « **Reply #12 on:** January 13, 2008, 02:39:30 PM »

Quote from: gamefreak on January 13, 2008, 01:50:24 PM

(can i wire a 1500 MaH in series with a 2000 MaH?)

NO

gamefreak · « **Reply #13 on:** January 13, 2008, 02:53:34 PM »

lol, ok then, is there a specific reason for no?

Also, on stepper motors, the common wire is supposed to be ground, right? I can only get my to work on positive, and not very well, could it be because im only giving it 5 volts?

Admin · « **Reply #14 on:** January 13, 2008, 04:23:20 PM »

Quote

is there a specific reason for no?

http://www.societyofrobots.com/robotforum/index.php?topic=2661.msg18460#msg18460

This question is asked too much . . . I'm adding it to the battery tutorial right now . . .

gamefreak · « **Reply #15 on:** January 13, 2008, 05:12:51 PM »

lol.

So would I be better off with a stepper either connected directly to the arm, or via a gear, or do the same with a DC motor, since the stepper runs off 12 volts and I am running everything else off of 6 it bulks up the arm, also, steppers seem to be a pain to drive

Admin · « **Reply #16 on:** January 13, 2008, 05:16:52 PM »

The only way to know would be to calculate torques . . .

gamefreak · « **Reply #17 on:** January 13, 2008, 08:22:34 PM »

lol, too bad im in the hypothetical phase, also since there is no gripper tutorial on this site, do you know of a good one I could look at? I thinking some sort of spring loaded wooden mechanism, with a wire connected to the servo, that way when the servo pulls it will open the gripper, and then it returns to the correct position.

SmAsH · « **Reply #18 on:** January 13, 2008, 08:34:46 PM »

ive only ever made one gripper and it operates with a motor up the arm pulls string which closes claw then releases string to open..with help of spring but string kept snapping......

gamefreak · « **Reply #19 on:** January 13, 2008, 09:17:15 PM »

lol, thats my basic idea, but use wire so there is less chance fo failure, and if its a stiff wire then i dont need a spring, I could attempt to make one of those double jointed things like on admins, but that would be a bit harder.

gamefreak · « **Reply #20 on:** January 14, 2008, 07:35:06 PM »

alright, today during class I was doodling and I had an idea, Admins gripper here uses high friction rubber to open and close the gripper(sounds inefficent to me), so I had the idea of replacing the plastic linkages with string attached to the widest part of my curved gripper and a rubber band going across, so here is a concept doodle, black is plasticy/wood, red is string, yellow is rubber band

SmAsH · « **Reply #21 on:** January 15, 2008, 05:33:59 AM »

i won $50 for entering the $40 robot (modified) into a school contest and winning

thanks to cooldog i think it was..

gamefreak · « **Reply #22 on:** January 16, 2008, 07:37:22 PM »

lol....ok.... so any ideas on the gripper design?

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Author Topic: TSA (Read 11402 times)