Author Topic: ok ive decided to use tracks for sonar bot (Read 4011 times)

SmAsH · « **on:** January 13, 2008, 02:55:30 AM »

ok ive decided on tracks....advice...how many wheels and do i need a motor for every wheel?

cooldog · « **Reply #1 on:** January 13, 2008, 08:17:09 AM »

you don't need to h ave a motor for every wheel and you need at leaset 2 depending on the size of your robot

also there not called wheels there called sprockets

airman00 · « **Reply #2 on:** January 13, 2008, 10:30:53 AM »

Just buy a kit!

and for the sonar I would recommend the PING ultrasonic sensor, its incredibly accurate and easy to use

Admin · « **Reply #3 on:** January 13, 2008, 12:10:40 PM »

I 2nd the advice for getting a track kit.

Tracks are a lot of work to make on your own.

SmAsH · « **Reply #4 on:** January 13, 2008, 02:49:12 PM »

hmm well ive got tracks that are on a robot rc so i might just rip out the insides (its hollow) and whola i got a $20 tank chasi! and with the sonar about how much does the price vary...?

Admin · « **Reply #5 on:** January 13, 2008, 04:01:21 PM »

Quote

with the sonar about how much does the price vary...?

$20 to $100, depending on features

SmAsH · « **Reply #6 on:** January 13, 2008, 04:08:56 PM »

hey admin would you say that the $20 would be very good? im on a VERY tight budget...i need the CHEAPEST materials i can get....and im starting to think if i cant make this with sonar i might just put in the $40 robot

but one thing i dont understand is how do i turn it into an obstcal avoider?

Admin · « **Reply #7 on:** January 13, 2008, 04:49:28 PM »

Well technically you can make your own sonar for like $10 . . . but its a question of how much your time is worth too.

I think ~$50 would be a good typical price for decent sonar.

You can find $30 sonar here:
http://www.acroname.com/robotics/parts/c_Sensors.html

(look other places too, thats just the first I found)

SmAsH · « **Reply #8 on:** January 13, 2008, 05:23:25 PM »

oh oh!! do you have a totourial on how to make your own? im dying of bordem here...its skool holidays.....but still very tight on budget ive got probibly 25-30$ left but i can probibly minus the motors and wheels from my budget...i reuse

Admin · « **Reply #9 on:** January 13, 2008, 05:29:20 PM »

have you searched google yet for a tutorial?

if it takes you 30 hours to get the sonar working, is it really worth the $15 you save? especially if you can make $10/hr at most summer jobs?

SmAsH · « **Reply #10 on:** January 13, 2008, 05:37:49 PM »

yea well with summer jobs im not alloud to work legally im 12...so yea...but just to prtect my circuit i bought some fuses....can i solder them on directly or do i need a holder for them?

airman00 · « **Reply #11 on:** January 13, 2008, 05:41:26 PM »

Parallax ping ultrasonic sensor is 30 bucks ( but i got it 10 bucks from a friend,

)

and I've heard good stuff about the Maxsonar EZ1 sensor ( 25 bucks )

They are both extremely easy to use! I would get those, and maybe mount them on a servo and have them scan!

Admin · « **Reply #12 on:** January 13, 2008, 06:03:04 PM »

Quote

fuses....can i solder them on directly or do i need a holder for them?

you need a holder

SmAsH · « **Reply #13 on:** January 13, 2008, 06:12:02 PM »

oh ok ill keep trying thanks for all your imput admin and airman00

hgordon · « **Reply #14 on:** January 13, 2008, 11:14:58 PM »

The Maxbotics sonar is a good choice - it is easy to interface, reasonable cost, and good performance. I'm using the LV-MaxSonar EZ0 because it has the widest beam, which is good for proximity sensing, but not for mapping.

Steel_monkey · « **Reply #15 on:** January 14, 2008, 01:14:12 PM »

SmAsH, I was researching net for a while for best sonar sensor schematic, and got some useful info (IMO, it is unacceptable for robot-builder hobbyst to buy thing that can be easily made). If You plan to use 1 MCU, it is possible not connect sonar with it avoiding another MCU with I2C. Also it is a wide area for experements. I am planning to make 10$ sonar, but not yet 100% sure about supply solution. If You need info, PM me.

SmAsH · « **Reply #16 on:** January 14, 2008, 07:17:38 PM »

yea ive looked around a bit too and i cant realy seem to find anything that really fits my needs...but for something else would it work if i had three high powered leds surrounding the light sensitive cell and the put duct tape around it so only reflected light would get it?

airman00 · « **Reply #17 on:** January 15, 2008, 06:16:59 AM »

Quote from: SmAsH on January 14, 2008, 07:17:38 PM

yea ive looked around a bit too and i cant realy seem to find anything that really fits my needs...but for something else would it work if i had three high powered leds surrounding the light sensitive cell and the put duct tape around it so only reflected light would get it?

NO!

Other light would get in and the amount of reflected light would not be bright at all! Nice idea though. Stick with sonar or make an IR rangefinder

Steel_monkey · « **Reply #18 on:** January 15, 2008, 10:16:23 AM »

If you are looking for CHEAPEST method of abstacle avoiding, You can use TSOP17xx ( for example TSOP1740). It is simple IR reciever for remote-controlled devices (TV, etc.), and it reacts only on 40 KHz modulated IR siganl (really, bursts of 40 KHz waves). So, if you take a IR LED and TSOP nearly at same dierection, light, reflected from obstacle will affect TSOP and cause sensing ( voltage of one pin changes). It is simpliest and cheapest (~0.5$ TSOP and 0.2$ IR led, 2 resistors and NPN transistor) way to detect something in front of your robot, but it has some drawbacks too ( not all bodies reflect light same way, for example mirror and wood will be sensed on different distance). And you need MCU to control voltage , turn on modulation and make decisions of course.

bukowski · « **Reply #19 on:** January 15, 2008, 10:23:09 AM »

Back to the track question...

Ive been looking into some ruggedly designed track that will not be too labor intensive.
Unfortunately, most of the "track kits" are either way too mickey mouse, or way too expensive. So, after some research I think that using conveyor chain would work great, if I could find the right size / pitch.

[

These look great, but the pitch is kind of big. The smallest diameter sprocket I could use is 4½ inches, which isn't going to work well for a "triangle track" configuration. The other drawback is you have to use special conveyor sprockets, which, of course, they want a mint for.

airman00 · « **Reply #20 on:** January 15, 2008, 10:35:36 AM »

do you know where i can buy such a chain and sprocket?

bukowski · « **Reply #21 on:** January 15, 2008, 10:44:05 AM »

There are a bunch of companies that sell different sizes / styles of conveyor chain. That one is manufactured by rexnord. http://pt.rexnord.com/products/e-catalog/products.aspx?catid=35

MSC Industrial has some that looks promising also, with a smaller pitch, but without the rubber feet.

I was so stoked on finding this stuff that I was going to wait until I was done and I could post triumphantly post pics, but hey, everyone here has helped me so much I just couldnt keep the goodies to myself.

airman00 · « **Reply #22 on:** January 15, 2008, 10:54:24 AM »

lol ,

thx bukowski!

can't wait for those pics

SmAsH · « **Reply #23 on:** January 15, 2008, 03:36:57 PM »

umm...there wont be any pics...my sister drove him into pool

oh well i'll have to kill her

airman00 · « **Reply #24 on:** January 15, 2008, 04:41:32 PM »

i meant pics of bukowski's treads

what pics are you talking about SmAsH?

SmAsH · « **Reply #25 on:** January 15, 2008, 04:45:27 PM »

i WAS talking about the pics of sonar bot but hes dead now

airman00 · « **Reply #26 on:** January 15, 2008, 04:46:56 PM »

so you can still take pictures of it, the robot will just be wet

SmAsH · « **Reply #27 on:** January 16, 2008, 02:10:24 PM »

yea its just drying in the laundry..ill post some pics once i test it again.

~smash

airman00 · « **Reply #28 on:** January 16, 2008, 02:30:17 PM »

ok cool

do you have any source code also?

SmAsH · « **Reply #29 on:** January 16, 2008, 02:32:04 PM »

i may not have saved it... $:-\$ sorry ill take a look anyways

~smash

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Author Topic: ok ive decided to use tracks for sonar bot (Read 4011 times)

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