Difference between revisions of "RC Lawn Mower"

Revision as of 15:36, 30 September 2010

Overview

Remote Controlled (RC) Lawn Mower that Ratmandu was talking about.
See example here: http://members.iinet.net.au/~tnpshow/RCLM/intro.htm

We have a mailing list for the mower here: http://lists.makerslocal.org/mailman/listinfo/rcmower

Pictures of the progress we're making are available here: RC Lawn Mower/Pictures

Volume 22 of Make Magazine Features a DIY RC Lawn Mower: http://www.makershed.com/ProductDetails.asp?ProductCode=9780596807177

Calendar

• September 21 2010, 5:30pm - 7:30pm: RC Mower Welding Session

Status

• Chassis
  • Sadly, Angela blew her knee out dancing at the kletch :( Don took up the welding torch and was able to attach one of the motor chassis to the main chassis. --Omegix 19:08, 28 September 2010 (CDT)
  • Angela got some practice in with the Welder. The scooter chassis needs to be angle ground smooth so that she can weld two flat surfaces together. --Omegix 12:44, 22 September 2010 (CDT)
  • Prepped the scooter chassis so it's ready to be welded to the main chassis. --Omegix 15:09, 20 September 2010 (CDT)
  • Ratmandu repaired the electrical short in the welder. All ready for the next welding session! --Omegix 15:09, 20 September 2010 (CDT)
  • MIG Welder at the shop currently isn't feeding the metal through. There appears to be an electrical fault causing the trigger to not close the connection to the electric motor that feeds the metal. Angela said she would come back for another welding session once we had the welder repaired. Anthony and Copie both said they would be willing to help weld as well (I think Copie said he has a welder he can bring from home if we need one). --Omegix 09:26, 15 September 2010 (CDT)
  • Don and Omegix cut the extra metal away from the scooter with an angle grinder. Need to build up chassis so that scooter has something to attach to. This is going to require someone with better welding skills than Don or I have :P Maybe Justin or Preaux would be up for it? Picture of Modified Scooter Assembly --Omegix 13:14, 24 August 2010 (CDT)
• Wheels
  • Wheels are currently flywheels and only turn in one direction (forward). Need to figure out how to get the wheels to turn in both directions when the motor spins in reverse. --Omegix 12:44, 22 September 2010 (CDT)
• Motor Control
  • Have purchased three of the MOSFETS used on the Victor 883 to see if I can repair it before committing to purchasing parts to create a brand new MC board (or purchasing an OTS board). --Omegix 14:31, 29 September 2010 (CDT)
  • Have contacted Micheal Spiceland about availability of spare motor controller. --Omegix 15:03, 29 September 2010 (CDT)
• Motors
  • New motor purchased today, its on its way. --Omegix 19:08, 28 September 2010 (CDT)
  • One of the Victor 883s won't turn the motor in reverse, the other one is working fine. Going to check with ratmandu if he has any extra mosfets to see if the Victor 883 can be repaired. --Omegix 12:44, 22 September 2010 (CDT)
    • This page may have the specs for the Victor 884 MOSFETS. Need to confirm they are the same MOSFETS on the Victor 883, and then compare to the MOSFET that ratmandu put on the broken Victor 883. --Omegix 13:29, 22 September 2010 (CDT)
    • Forum opinions seems to indicate that one burned out MOSFET would not disable the Victor's ability to drive in a direction, and that an entire leg of the H-bridge (although unlikely) would have be burned out. --Omegix 13:29, 22 September 2010 (CDT)
  • Confirmed that the motors worked with the Victor 883 motor controllers. Kinsey provided a PWM signal to the control board using an Arduino. We noticed that the motors were unresponsive to going in reverse. This may be a bad control board, or a motor that can't go in reverse. Will investigate soon --Omegix 15:09, 20 September 2010 (CDT)
    • Schematic confirms that motor can turn in either direction. Will confirm its a busted motor control board on Tuesday by testing with the never-been-repaired Victor 883. --Omegix 15:28, 20 September 2010 (CDT)
  • The other test of the battery charger, batteries, and motor went well: http://www.youtube.com/watch?feature=youtube_gdata&v=muSJdvpVChs
  • The extra new motor and assembly had a burned out motor. Need to call micheal and see if he has any extra, or potentially purchase a replacement motor --Omegix 19:02, 26 July 2010 (CDT)
  • An additional scooter frame with motor and wheel has been given to us by Micheal, as well as two batteries to power the motors. --Omegix 10:45, 18 July 2010 (CDT)
  • Have left a voicemail for Micheal Spiceland inquiring about the motors. --Omegix 10:48, 13 July 2010 (CDT)
  • Opticron's coworker (the one that supplied the scooter)is checking into what scooter components and motors he has left that he would be willing to part with for low, low prices. --Omegix 13:56, 9 July 2010 (CDT)
• Turns out friction drives are much better suited for smooth surfaces. This put us back to an original problem, motors. Don looked around the store room and found an electric scooter engine that Opticron had donated to the shop. With one more 250W motor, wheel assembly and some batteries, we should have a drive solution.
  • http://www.monsterscooterparts.com/openloopchain.html
  • http://www.monsterscooterparts.com/24v250wmotor.html
  • http://www.monsterscooterparts.com/12-2-57-203-rear-wheel-assembly-curved-spokes.html
• New Approach: So far this project has been building a RC Mower, Preaux suggested a new approach, build an RC frame that a lawn mower attaches to. This will allow you to change out what you're driving around, including an RC Drink Cooler.
• Drive System: The Motors do not have a slip differential built into them, meaning that when they get jammed on something, the motor will keep turning and eventually burn itself out. Preaux suggested using a friction drive, where the thick rubber wheels connected to the motors lay up against the bicycle wheels. As the motor turns, the bicycle wheel will turn in the opposite direction. If the wheels hit something, the motor will turn grinding against the bicycle wheel instead of on itself. Probably bad for the wheel, but those are cheaper to replace than motors.

To-Do

• Purcahse parts to make a motor controller to replace the victor 883
• Need to attach last scooter motors\wheels to chassis
• Purchase 22" metal plating to stretch across the back of the chassis. This is where the circuitry and batteries will be mounted.
• Purchase Another length of Square tubing.
• Purchase replacement motor: Ebay

Completed

Materials

Potential Materials

• Bicycle Gear Chains
• Bluetooth to Serial module (for controlling via internet)

Materials On Hand

• On Switch (provided by Preaux)
• Big Red Momentary Kill Switch (provided by Preaux)
  • Could put this in between the wire connecting to the spark plug
• Two 8" swivel castor wheels ($14 each)
• Metal Bars for chassis (See metal chassis from example above)
  • Purchased 20' of 1" 14 gauge square steel for $18. ($14 for the bar, $3 to have it cut)
  • Two 48"
  • Two 22"
  • One Solid piece of whatever was left.
• Two Bicycle Wheels
  • Two tubes purchased for the wheels. ($6 each)
• Lawn Mower (retrieved from Makers Local craigslist add: http://huntsville.craigslist.org/wan/1715017438.html) ($30 for two mowers)
• Sea Foam (engine cleaner. the mower took a bit to stay running the first time we cranked it). $10
  • Omegix has in the trunk of his car.
• Motor Control
  • The Current Victor 883 on the board has a burned out FET, causing the motor to only spin in one direction. Ratmandu said he might be able to fix it with tools like what he has at work, but not with the soldering tools at the shop.
    • Replacement FET didn't take, purcahsed three MOSFETS like the ones originally installed on the Victor 883. $12.
  • PreauxPhoto has one of these available: http://www.firstwiki.net/index.php/Victor_884

• • • This microcontroller will take in PWM and output enough current to drive larger motors
• Motors
  • Purchased another 24V 13.7A motor identical to the working one we got from Micheal Spiceland / Opticron. $33
  • PreauxPhoto has 12V DC Motors
• Battery (for powering the electric motors)
  • Spacefelix said he would donate his battery in the storage room to the project if we wanted it
• Battery (for powering the electronics)
  • Preaux has provided a special battery that is resistant to loss of power due to vibrations, etc)
  • Currently in Omegix car trunk. Omegix 12:40, 26 May 2010 (CDT)
  • battery dimensions: 4.5"D x 8.5"W x 5.5"T
• RC Transmitter and Receiver Unit (hobby RC receivers output PWM signal)
  • PreauxPhoto has