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Need Help Extending Wires To Drive Train On My Omnibot

Hey guys, I've adapted the chassis of an Omnibot 2000 a bit and I need to extend the wires to reach the wheels/motors. I'm going to put in my EZ-B goodies when they arrive but it's back ordered and my sister's class needs a mascot for their new robotics team next week. Any advice?

I started with a glitchy omnibot but after some soldering repairs and a new capacitor the original system worked great, UNTIL I cut the wires to the drive train. I just attached a longer set of wires with a splice but now I've got no response from the wheels. I tried a wire nut and then a shrink tube but no response. I'm no electrical engineer, I learn by burning things up. Can anyone tell me what's wrong or suggest a work-around? I just need a solution that will last for a month until EZ-B arrives. Also, I admit it really bugs me that I can't get it to work myself. Maybe the new length and splice create a power drop? ANY ideas welcome, thanks.

Jenn

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#1  

can you messure the power you have on the wire?

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nice robot

#2  

You most likely have a break in the wire(s) somewhere... grab a multimeter and check your wire continuity... or you can re-trace the wiring, replacing or re-splice them again... Did you use the right gauge of wire (thickness)...? adding a couple of feet of wire (same gauge) wouldn't cause that much of a power drop...

United Kingdom
#3  

The volt drop on that length of wire would be minimal and rather than not work would only slow the motors down. You would still get some movement or if nothing else some noises.

As Richard R suggested, check the wires with a multimeter set to ohms or continuity.

#5  

Very nice looking robot!

When I run into wiring issues, here is what I do:

1.) Make sure you battery is good and has a full charge and power is reaching you controller.

2.) Double check your work, this includes checking my solder joints and checking wire A goes to there it is suppose to and is not switched with wire B.

3.) Check your wires to continuity. You would want to touch one probe side to the metal tab on the motor and the other to then end of your wire (preferable disconnected from the motor controller or whatever it plugs into). You should get a reading that there is continuity (if not, something went wrong within the wire).

(Assuming you have a mulitimeter, there should be a little diode symbol or it might look like a speaker making noise symbol...if you have never used this, you can test it on a piece of wire you know is good or a piece of metal or touch the probe ends of the meter together....the value on the meter should change to perhaps show a .1 or it should make a noise....meters will vary. If you don't have a meter, if you have a Harbor Freight store near by they have pretty cheap digital meters for under $10...sometimes for under $3 if they are a sale item.)

4.) Next I like to make sure everything works as I would expect with power supplied while things are disconnected. In your case, if you take the motor wires and apply power to them (not sure the motor power requirements for an Omni bot...6volts maybe?) you should be able to make the motor move forward and reverse by switch the pos and neg of the battery to the motor wires. Once the motors check out good, make sure your controller works by connecting power to the controller and instead of connecting the motors to the motor output, you can connect your multimeter to those lines, just make sure you set your meter to a voltage range that can absorb what is being output. So if the motors are 6 volts, a setting of 20 volts DC on the meter should be fine. If the controller or remote commands the robot to go forward you should see a voltage reading on the meter, if you don't, something might be wrong with the controller. Your meter might show a neg or pos number for forward depending on how you connected your meter to the motor output of the controller (unless the output connecter is marked with a + or - it might be hard to determine until you check it with a meter).

5.) Last connect one component back at a time. After all, every thing should check out individually, so now you can reconnect one motor...make sure it works. Then reconnect the second motor. If one or the other motor work at this point but not both at the same time, it would seem to indicate a power issue (perhaps not enough).

#6  

Also, welcome to the group!

Your first question....are you looking for advice on what to do with your robot for your sisters class until your EZ-Robot order arrives? If the Omni bot guts are working, I'd say why not keep them in there until your order comes in? I'd consider it pretty cool to see the 80's style robot guts in action....then get to see what the robot can do with best of 2014 technology in it. Maybe do a before and after video?

#7  

Oh my ! MY " JARVIS2000 " has a cousin now!

On the drive train i would first test the motors and gearbox direct to battery and make sure they are good. You can give them 6 to 12 volts no problem. Once you are sure the motors and gearbox is functioning move on to checking the wires like others have noted. Breaks in wires can happen as well as a bad solder joint too.

#8  

Wow! I checked back in just in case someone replied but I didn't expect all the great input, you guys are awesome. I do have a multimeter and I didn't think to check the wires themselves (oops), I was concentrating on the solder joints. I'll check the wiring diagram too in case I switched up the connections.

The gauge on the new wire is good but I did use solid instead of matching the vintage stranded original. Problem? I'll also check each motor with power to make sure I didn't somehow burn up the motors and I'll use the multimeter to check everywhere.

Justin, I'm not sure what my sister has planned for the kids. The local high school robotics team is coming out to help her 5th grade team get started in a Lego First league. Her 5th graders are pretty excited. I showed her Josh Starnes's Jarvis omnibot and they wanted something like that for a mascot. Granted, Arlan is not nearly as cool but he does have a neat little keyed locker for her purse (that's girly robotics).

Looks like a long evening of trouble-shooting and football tonight. I'll post back to let you know how it goes. I really appreciate the help!

Jenn

#9  

Ha,ha... football... You are definitely an all American Yankee girl... From Iowa or Wisconsin, midwest?

The type of wiring you used is fine by the way....

#10  

Hey Josh, I didn't see your post before I finished my reply. Yes, Arlan is Jarvis-inspired. I tried to talk the kids into a different color (for originality) but you used their school colors so...oh well. :)

#11  

It's Texas, Richard. The home of Friday night lights. Everyone here loves football, not a lot of robotics help though, lol.

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Belgium
#12  

beetlesmart

can you use this picture.?

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#13  

Umm, yikes. I've posted one pic for my avatar and one for robot help. Both were sideways and both were re-posted upright by this forum. I CAN flip my pics, it just doesn't bother me. Sorry guys, I'll try to mind my P's and Q's when posting.

I just got home and re-read all of the advice before I get started. Thanks again.

#14  

It only bothers the noobs i believe , lol my picture is sideways , always has been.;)

United Kingdom
#15  

Sideways pictures bother me, it is a simple ctrl + , or ctrl + . in windows and shows laziness to me, the same way incorrect spelling and grammar and even failing to hit the shift key when a letter needs to be capitalised bothers me. I guess it's the burden of being a perfectionist. It doesn't bother me enough to mention it though (however since it was brought up I'm mentioning it, it's not only "the noobs").

There's no need to mind your Ps and Qs provided everything is legible though.

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Belgium
#17  

also using caps lock is like chouting to someone. lets not blow this up,its just a picture.

i agree whit rich.:D

#18  

Oh earlier you asked about wire. It is best to use stranded for several reasons.

  1. Higher current capacity than a solid core if the same gauge.

  2. Less likely to break wire inside because stranded is more flexible.

  3. Soldering a good connection is easier because the crevices between the wire strands allow solder to flow through and around them for more surface area connection.

If all you have is solid wire , use it sparingly as it is harder to work with and generally considered a "cheaper" form of wire.

Wirenuts may not be making a good connection. Soldering them and heat shrink over is best. Using crimp quick connects is a descent second option.

you may have just swapped a couple connections on accident and now neither motor turns , thats possible. There are 6 wires for motors coming out. 2 for each motor. The third motor switches gears from high to low.

When soldering wire a 30 watt iron or higher is fastest and 60/40 rosin core solder is the most forgiving for great connections.

@Dave , people usually turn their heads to one side after talking to me a few minutes anyways lol:)

#19  

Oh and your certainly welcome to duplicate any of my builds you see. I try to document well enough for others to copy my work. Its really flattering and very cool your making a robot for your kids!

#22  

You guys crack me up:)

The wheels are working, it was a wire problem. When I didn't have power on the motor I assumed I had a bad wire or splice in my new wire work. After replacing the extensions three times without success I finally read through your comments again.

I retraced all the wires and checked for breaks (thank you Richard) and finally found a nick on the underside of the original omnibot wire. I must have nicked it while I was messing with it. It was a forehead-slapping moment to be sure, there may have also been quietly mumbled curse words.

Rich: thank you for eliminating my power drop concern

Nomad: thank you for reminding me to check every piece of wire.

Justin: thanks for your orderly well-organized checklist. It could have easily been any of those problems. I'm definitely tucking away that list for future use. PS love the earthquake anchorman pic, lol

Josh: thank you for the inspiration and the wire tips. I did end up replacing all of my solid wire with stranded wire.

Okay, so that build is done until EZ-B gets here. I'm starting my next one (fair warning). So far I've got a roomba, another omnibot, and a Larson scanner. Who knows? You guys are the greatest.

Jenn

#25  

God bless Texas. Greetings from Buster, Buster Jr. and Roger the bookmaker in Kerrville Texas.

#26  

Hey Bookmaker,

I think this thread is over but I couldn't resist saying howdy to a fellow Texan, especially one so close to River's Edge (I think it's called 1011 now) and those yummy burgers. See you on the community boards.

Jenn

#27  

That's awesome Jenn, I'm glad you found the issue. You are welcome! I'm looking forward to seeing how your robot progresses.

#28  

Hello Jenn,

What did you use to extend the base?

#29  

Sfoy, in case you are still around....I used a heavy duty plastic file storage box with an open top from Ikea. I cut a wood top (3/4" birch) to enclose the box and routered the edges to transition from the file box to the Omnibot frame. In the front of the box I cut a square around the vented center and added trim, hinges, and a lock to create a locker instead of an inaccessible base.