Micro RC Car

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Remote controls cars are now widely available, however there's one astounding model that one can scratch-build. It measures merely 2inches long but is equipped with proportional control system including 12step steering control, headlights and more!

Below is the complete list of materials required.

Step 1: Materials Required

Chassis:

1.5mm Balsa wood

CA glue

Printed shell template

Power system:

2ch 2.4Ghz micro Rx

1S 3.7V 50mAh Lithium battery

4x12mm coreless motor

Micro plastic gears

25-70ohm Actuator coil/magnets

Misc:

0805 SMD white LED

CF/ steel axle rods, 1mm diameter

Glue gun

Soldering iron

Step 2: Making the Chassis and Geardrive System

The shell is made by printing a paper car template onto a 200gsm glossy paper.

Next, Ive glued the LED's onto the shell using epoxy and soldered them is series using enameled copper wire.

Making the chassis:

I have used 1.5mm Balsa as its easier to work with but it can also be made using plastic. The rear wheel axle with a spur gear is slipped into a tube(preferably plastic with smooth finish to reduce friction) and glued onto the base.Now the wheels are firmly fixed onto the axle. The same procedure goes on for the front wheels too except that, the axle is kept stationary and wheels are free to rotate about the carbon fibre rod.

Steering control:

An off the shelf actuator can be used for steering the model, else the same can be made by making a small coil with resistance of about 25-70ohms and placing a neodymium magnet in it. The ends of the coil are directly soldered onto the receiver.

Step 3: Mounting Receiver, Motor and Battery

A 4x12mm coreless motor with pinion gear is glued onto the chassis by aligning it with the spur gear on the rear axle.

The wires of the motor are rooted to the speed controller and then to the receiver.

After ensuring the functionality of every control, its time to fix the battery and receiver in place by either using tape or hot glue. This can sometimes get tricky with bulking stuff like a larger battery, receiver or longer connecting wires, they need to be squeezed in order to accommodate in the given space.

Step 4: Done!

The chassis and the electronics are then en capsuled by the shell. Make sure that there's a little clearance between the wheels and the shell.

It's now ready to run!

Here's a short video of the test run.

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    25 Discussions

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    KRP-01mr.knex13

    Reply 4 weeks ago

    That one is only for servo motor.

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    cspirito

    4 weeks ago on Step 1

    Please post sources and prices for the material and parts used.
    Hard to see how it steers.

    2 replies
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    wclapiecspirito

    Reply 4 weeks ago

    This was my question as well. I could source all the parts I guess but I got complacent when the authors showed links for their parts sources. I missed that in your project?

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    KRP-01cspirito

    Reply 4 weeks ago

    I'll update the links soon.

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    dick55

    4 weeks ago

    An interesting but poor Instructable. Too many details omitted.

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    Steinzel

    4 weeks ago

    I'm not fully understanding how the steering mechanism works. Can you show a little more detail on that?
    Very cool project, Thanks!

    3 replies
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    KRP-01Steinzel

    Reply 4 weeks ago

    Here's how an actuator works... It's basically an electromagnet with a small neodymium magnet placed inside the coil. The amount of deflection is controlled by varying the current through the coil. To make it deflect in opposite direction, the direction of the current is reversed. All this is controlled through the Receiver.
    The actuator is directly connected to the front axle.

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    AKOldmanKRP-01

    Reply 4 weeks ago

    Thanks for the explanation of how it works. Now, how about a picture, close up, of how the front axle is connected to the actuator and how the assembly is able to pivot.

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    SteinzelAKOldman

    Reply 4 weeks ago

    ...also, it seems like the "electromagnet" would have to push against or pull on something. It's just there in the open air. What attracts or repells the electromagnet to convince the axle to pivot?

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    jlms

    4 weeks ago

    I think you are missing completely the point of publishing your instructable, you shared the least interesting parts of whatever you did to make this project work.

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    baratacus

    4 weeks ago on Introduction

    From the looks of it. Your coil actuator is connected to the front axle. I assume you plan on turning the car by pivoting the whole axle. That will cause the front wheels to move forward ahead of the car and the other backwards into the body in order to effectively turn the vehicle. Most micro rc cars use steering knuckles and a pushed or a rack and pinion system to turn the front wheels. You would have much less resistance against your actuator.

    1 reply
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    KRP-01baratacus

    Reply 4 weeks ago

    Yes, the whole axle is pivoted at centre.
    The model weighs just a few grams and use of a gearbox for steering is not necessary.
    At this scale, an actuator will suffice.

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    zanod

    4 weeks ago

    A lovely little model, but an unusually poorly described instructable. For example, I just went looking for the micro Rx, but after 20 minutes on the web, I didn't find one. The one and only source I found said "Sold out". Your description of the steering mechanism is also wanting.

    1 reply
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    baratacuszanod

    Reply 4 weeks ago

    Most cheap micro rc planes have proportional actuator controlled rudder. The motor and gears and battery can also be scavenged from the plane. Only downside is that there's usually only forward , no reverse. Hobbyking used to have good micro rc boards and speed controlers. You could probably put one of these together with new parts for around $30 usd

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    sitearm

    4 weeks ago on Step 3

    Very cute! I have to admit it made me think of The Fifth Element movie where the robot cockroach was eavesdropping on the world president.

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    sp9mrn

    4 weeks ago

    OK, but the question is - source of small receiver which can be paired with T9x.
    Without it project is impossible to build. So source please.

    2 replies
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    KRP-01sp9mrn

    Reply 4 weeks ago

    The receiver that I'm using is a very old one... may not be available now. However similar ones like 'Deltang micro receivers' with DSM2 protocol can be used.
    To hook it up to 9X Tx, it would still require a DSM2 module.

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    Rambo32

    4 weeks ago

    where did you buy the reciever??