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Thread: mynyr

  1. #1
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    mynyr

    mynyr (My New Year's Resolution - pronounced 'miner') is a dinky little rover that should one day become a vacuum cleaner and general roving testbed (going to use lessons learned on this trash bot to eventually upgrade Darsha a bit).

    I'm posting this now in an effort to maintain what little momentum I have built up, since USPS seems to have the wrong destination address for my package from allelectronics which contains the stepper motors, gears, and laser diodes I require to actually get this thing running. Guilt me into finishing this project, forum-goers. PLEASE!!!!!

    Chassis: the metal mounting plate of a big breadboard - the cheapo rubber bumpers wouldn't stick to the bottom and since I would be needing the electronics, I figured 'why not?' It's just the right form factor for what I was planning, and it will not be too difficult to attach some aluminium angle to stiffen it up and to also mount the motors and gear train. May eventually upgrade to t-slot cut to size from misumi, but at that point it would probably be a completely new bot.

    Drivetrain: an undecided combination of the 20 sets of five plastic gears from allelectronics driven by $2 24V stepper motors. If the motors don't work well enough, I've got two sets of much bigger and better steppers to replace them.

    Wheels: 4" Vex mecanum wheel set.

    Electronics: assortment of atmega168/328, pololu A4983 stepper drivers from the 3d printer I never finished about 2 years ago (also the source of the spare steppers), 3.3V and 5V murata voltage regulators, etc. Maybe a raspberry-pi or panda board when it gets running with any consistency.

    Power: 4S LiFePO4 (yet to be purchased) maybe 10Ah, but probably 20Ah.

    Sensors: none yet. Could toss the spare CM-730 on the bot to get 3-axes linear acceleration and 3-axes rotation velocity, but plan to use a MultiWii from HobbyKing whenever it arrives (3-axes acc, 3-axes gyro, 3-axes mag, plus barometer and ATmega328). In the process of setting up a triangulating laser distance sensor using a TSL1402R and ATmega328, but the TSL1402 arrived only a couple hours ago and I can't get the lasers and other parts until at least Wednesday. Of course, if I can't get the sub-pixel position interpolation as fine-grained as I hope, then it won't matter anyway as the unit will not be able to see with much consistency/accuracy beyond ~1m. I'm hesitant to even post about the sensor because it will likely end in failure (~1/3 the number of pixels with each ~10 times the size as the sensor used in the RevoLDS paper. ~1/8 the pixels with each almost 16 times wider than the final sensor used in the Neato LDS. ...then getting all the optics aligned, woof).

    Accessories: 12/24V blower, a pair of counter-rotating brushes, dust bin, charging base station, ???
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    [git][mech][hack]
    gives free advice only on public threads

  2. #2
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    Re: mynyr

    I like the name Is this going to be a larger bot than the Roomba/Neato, or just taller?

    Also, the MultiWii boards are intriguing... I think that may be my next acquisition.

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    Re: mynyr

    Quote Originally Posted by Gertlex View Post
    I like the name Is this going to be a larger bot than the Roomba/Neato, or just taller?
    Not really sure. The breadboard is ~8"x~9.5" and the battery I'm drooling over would easily fit under that footprint while adding only three inches of height.
    Quote Originally Posted by Gertlex View Post
    Also, the MultiWii boards are intriguing... I think that may be my next acquisition.
    I originally added them to the order just to make it worth the crazy expensive shipping from Hong Kong, but they are rather nice looking. I'll know more when they arrive ...whenever that will be... Also picked up one of their little ATmega socket programming dongles so that I will have one less possible cause of more soldering scars.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    [git][mech][hack]
    gives free advice only on public threads

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    Re: mynyr

    Lesson #1: Double and triple check all wiring before applying power.
    Lesson #2: If a part overheats and/or goes into shutdown, recheck ALL wiring.
    Lesson #3: If a part repeatedly overheats and/or goes into shutdown SEE #1 and #2!!!

    Down to three A4983 driver boards. Missed a wiring mistake and applied 12V input to the A4983 instead of the 5V output of the murata regulator. At least I did not kill that as well.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    [git][mech][hack]
    gives free advice only on public threads

  5. #5
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    Re: mynyr

    oooooohhh.... I'm liking these mecanum wheels, nice and smooth and quiet with no sticking rollers or constant thunk-thunk-thunking like the frelling expensive omni-wheels on Darsha. Only complaint is that I appear to have lost one of the 12" shafts in packing or shipping (several holes in the plastic bag and the three shaft were just sitting in the box). They wedge into the 4mm holes of the cheapo plastic gears quite nicely ...or not - just stripped the little corners the shaft had cut into the center. ...and the power wire broke off the laser pointer module during shipping, so that's another thing to fix.
    Last edited by tician; 01-04-2013 at 08:24 PM.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    [git][mech][hack]
    gives free advice only on public threads

  6. #6
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    Re: mynyr

    As is wont to happen, I have been neglecting this and several other projects.

    One painful caveat of buying surplus is that you rarely know for certain the specs of what you buy. Turns out, after a bit more searching, the beefier stepper motors are rated for ~6A and the voltage spikes produced by the one I was testing were more than enough to fry a second stepper board. That left me a bit hesitant to continue, and classes starting*, and USDA project wrap-up, and brain still really wrong... really not enjoying the dreams and night sweats the mirtazapine has been causing... bleh. At least I've started learning git for reals (since I should be using ros a lot more soon).

    * Why does an engineering grad-student take so many CSCI-courses?
    CSCI 8920 - Decision Making Under Uncertainty
    CSCI 8940 - Computational Intelligence
    CSCI 8950 - Machine Learning (audit - don't think my crappy brain will work well enough for all three)
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    [git][mech][hack]
    gives free advice only on public threads

  7. #7
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    Re: mynyr

    Out of curiosity, how many courses do you have to take as a grad student? I have to take a grand total of 3 for my PhD, and two of those were waived because there was nothing else of relevance that I could take.

    Will be very interested to see how you go with the laser sensor, I've been tossing up building my own as well so this'll be very useful information.

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    Re: mynyr

    24 hours total with a minimum of 12 grad-only hours, plus three hours for thesis writing (7300) and three hours for thesis research (7000). Since it's a research university and there are not always a lot of relevant courses, ENGR 7000 (research) is mostly a filler class that can be taken each semester for 1-9 hours and repeated for a total of 45 hours. The assistantship that's paying my tuition requires 15 hours during spring and fall, and 12 hours during summer. I went a little heavy on the non-research/non-thesis hours last semester so I only need two more hours of grad-only credit (taking 8), which is a good thing since we're not sure I will have funding after this semester (only need three hours of 7300 after this semester).
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    [git][mech][hack]
    gives free advice only on public threads

  9. #9
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    Re: mynyr

    Progress?!??!


  10. #10
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    Re: mynyr

    None. Trying to finish a genetic algorithm project and paper before the tuesday deadline. I had barely started before yesterday and then I wasted upwards of 10 hours last night letting a nonsensical octave script run.

    I really hate my brain. I wish I could trade it in for a new one.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    [git][mech][hack]
    gives free advice only on public threads

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