REQUEST FOR HELP: 6th grade science fair project, simple robot

Hi everyone!

New member with a request for assistance from those far more learned in robotics than I and my 12yr old daughter.

She entered science fair recently and wanted to do a simple robot. Well, long story short I’m up against the wall with time - this thing needs to be handed on March 4th.

This robot is very simple. We simply need it to move forward and backward, turn around, plus raise a lower a scoop in the front of the unit. She will navigate it around the floor, scoop up a cotton ball or something else small and light, and deposit it in a cup.

Simple, one-time use deal. I highly doubt this will ever be used for anything again - so I need it to be as cheap as possible to build.

In doing her research she figured that she needs:

]2 servos (continuous?) for the wheels/:m]
]1 servo (rotational?) for the scoop arm/:m]
]2 large wheels plus 2 swivel wheels in the front and back of the unit for stabilization/:m]
]1 receiver /:m]
]1 controller – I saw one that wired directly to the device which I’m guessing would eliminate the need for the receiver./:m]
]1 battery/:m]
]/:m]

Is this the correct list of parts we would need for this type of project? Is there anything we’re missing? I’m sure there has to be at least a few things we’ve forgotten.

Additionally the battery MAY not be needed, since she would like to make it lemon powered. She found a tutorial somewhere that helps describe this process and give a rough estimate of the number of lemnos nedeed to produce the power for the unit. We are willing to forgoe this option in the interests of time and simplifying the project…but if we can include it this would be a plus.

I’m seeking any and all advice on this project. Unfortunately we are very pressed for time, so I will need to purchase the parts tomorrow to get them to us in NJ fast enough.

I went through the store on robotshop.com and came up with the parts listed below. It does NOT include the battery, connectors for the wheels or wires, scoop arm, etc. So I’ll need help there as well.

]2 - RB-Fit-02/:m]
]2 - RB-Ban-142/:m]
]1 - RB-Tam-13/:m]
]/:m]

We’re desperate and will take any help we can get.

Thank you. I will monitor the forum for replies and private messages, but you can also email me directly at [email protected]

I really appreciate your help.

-Rob

Coleman,

First off, let me thank you for replying - I really appreciate you taking the time to clarify things for us.

So, if I’m following you correctly the following list of parts would be well-suited to our project:

1x RB-Tam-01 <-- gear box for wheels (which would attach to the frame)
1x RB-Tam-02 <-- gear box for scoop arm (which would attach to the frame)
1x RB-Tam-13 <-- wired 4-channel controller (which connects to the 2 gear box/motors)
1x RB-Tam-08 <-- wheels and associated connectors (which would be connected to the Tam-01 gear box)
1x RB-Tam-82 <-- arm set (I’m assuming to construct the scoop?) which would be connected to the Tam-02 gear box

…and then we need to build a lightweight frame of some sort and assemble/test the robot.

What I’m not seeing - or just not understanding - is the power source. What would we need to run those motors? I’ll take a look to see if I can find one, since I’m sure we need one - but then again I’m not that sure.

Is that right?

I look forward to hearing from you again.

Thanks!
-Rob

Be careful about a wired receiver - it may be for DC motors rather than servos. Also, the wheels should not be too large. You’ll also need a frame.

The number of lemons needed to power three motors would likely add too much weight to the robot. Strongly advise against including this feature given your time constraints.

RB-Fit-02 is a small servo - so don’t expect to make the robot too large.
The wheel is far too large for this servo.
The controller you selected cannot control continuous rotation servos.

Consider the following as alternatives:
RB-Tam-13 can control four DC gear motors. Suggest using the Tamiya Twin Motor Gear Box as drive motors, and a crank axle gear box to raise / lower the scoop. By using only Tamiya products, you can easily attach wheels and other frame components. This would also be the least expensive approach.

Correct. You can even save some time with additional components for the frame (up to you, just providing options):

robotshop.com/tamiya-ball-caster-2.html
robotshop.com/tamiya-long-universal-arm-set-2.html
robotshop.com/tamiya-pulley-set-large-2.html
robotshop.com/tamiya-universal-arm-set-2.html
robotshop.com/tamiya-universal-plate-2.html
robotshop.com/tamiya-universal-plate-set-2pcs-2.html

There are batteries (sold separately) which you place inside the wired controller which power the motors.

Essentially you would be creating a custom version of this:
robotshop.com/tamiya-70162-robot-construction-kit-6.html