Lego Mini Cooper RC Conversion with SBrick

Last time, I used a cheap RC car components to do the conversion.  By knowing the SBrick, a Bluetooth device that can control 4 Lego motors through your smart phone, I purchased one SBrick and one set of Lego IR remote control with two M motors.

The conversion is mainly in three parts:

1.  The Battery Case and Rear Drive – by moving the rear seat one block forward, I could have enough room for the Lego 8111 battery case.  The driven motor was installed in parallel so as to provide room for the battery case.

2.   Front Steering & Return-to-centre Mechanism – most of the conversion will use Lego 88004 servo motor, when cutting off the power, the shaft returned to centre.  As I was not going to invest an expensive servo motor, I searched the Internet and found lot of return-to-centre mechanism to consider.  It consists of a few Lego block and a rubber band. The front steering consists of a linear tooth gear and round gear.

3.     Position of the SBrick – as it is not so big, I could put it in the front compartment.

To look nice, I added a pair of LED front light as well.

The test drive revealed two dissatisfaction.  Due to limited room inside the front wheel compartments, the front steering angle was small thus resulting a larger turning radius.  When controlling two movements through the SBrick, the movements were slow.  It might be caused by small batteries inside the compact battery case, AAAs instead of AAs.

As the SBrick is quite expensive, the price is twice of one set Lego IR remote control, I later changed it to Lego IR remote control.  As the IR received is higher than the SBrick, I needed to modify the front bonnet.  

  

Lego Mini Cooper RC Conversion

I am not a fan of Lego but fascinating about people using different shape and colour of Lego blocks to create huge structures and models.  In memory of the old Mini that I had driven for a short period of time when I was studying in UK, I purchased a Lego Mini Cooper model box.

It consists of more than 1,000 pieces of blocks with two books of instruction.  It took me almost 6 hours to complete the installation.  Without the instruction books, I admitted that I would not be able to complete the installation.  No wonder this Mini Cooper model is suitable for age 16+.

Apart from cycling, my other hobby is to do RC conversion for large scaled model.  The size of this Mini Cooper is definitely worthy to give it a try.  The simple way to do the conversion is to buy a similar sized RC model car and transfer all the motors, controller and battery case. 

Firstly, I needed to move the upper part of the complete model to a Lego board and review whether there is enough room to house the above components on the chassis.  Eventhough, I had completed the installation before, it took me two painstaking hours to do the transfer.  It reviewed that I might have enough room to do so.

Secondly, I have to transfer the chassis to a Lego board, cut into shape as per the original.  The board would give enough strength to support as the original chassis of which were made of long and thin Lego blocks and plates. 

Thirdly, I purchased a cheap Chinese made imitation of Lego block RC car and used the driving, steering and remote control components for the conversion.  I purchased another set for my sister-in-law’s son, while I retained the chassis, he could have two sets of blocks for one chassis.

Fourthly, I cut the chassis into pieces, with cutting and drilling, and assembled the steering, driving and remote control on the Lego board.  As these components were larger than I expected, I anticipated that I would have difficulties putting back the upper part of the model.

Finally, the upper part was put back on the chassis.  I required to cut some of the blocks obstructed by the bolts and nuts, motors, etc.  It was another painstaking few hours.

The test drive has shown that the Mini Cooper runs smoothly most of time.  But because the model was not designed to turn, front wheel compartment’s space was very limited and the turning radius was only 15 degree instead of 30 degree.  However, I had lot of fun doing the conversion and look forward to having another project.