A car for RATTIES.

There are 2 versions:

• A FWD version
• An AWD version

The FWD version uses 2 bearings and 2 motors because I had 2 bearings lying around.

The AWD version uses 4 motors connected in parallel.

Parts you need:

• 2 or 4 12V 10rpm DC Electric Motors.
• 4 Flange Coupling Connectors
• 3 SPST or DPST or SPDT Microlimit Switches.
• 5L Tuperrware Box for the ratties
• 24 m3 bolts, 24 m3 nuts, 8 m4 bolts, and 8 m4 nuts, and m2 Threaded rod and 4 m2 nuts .
• 4 22mm outer,8mm inner, 7mm Width Bearings (Part number : 608 2Z [Y]).
• 4 9V Battery Connectors
• 4 9V Batteries
• 2 White and 2 Red 10mm LEDs
• 2 Yellow 5mm LEDs
• Arduino Nano Everyday/Classic
• Breadboard + Wires
• Dual Motor Controller
• Toggle Switch
• Spade connectors
• Dupont Connectors
• JST-XH Connectors

Tools you'll need:

• A drill with drill bits.
• A dremel or a cutting disc
• Screwdriver
• Soldering iron
• Crimping tool
• Glue

PPE you'll need:

• Safety Glasses
• Fume extractor

Tutorials

• Arduino Tutorials.
• Soldering tutorials.
• Pause at height

Instructions

Instruction video coming soon.....
Watch the youtube video [here]().

28/04/2024 V1.1: Moved bolt holes for motor wheel from 8.5mm to 8mm spacing for better fit on flange coupler, and also added a centre hole to help secure the wheel to the motor using another m3 bolt. Increased screw hole for B2B_B and B2B_A from 7.5mm to 13mm so washer and bolt squeeze against bearing as designed. Changed nut on bearing wheels from captive to normal as the TPU didnt have enough structural integrity to stop the nut from spinning inside the wheel and also required a very precise bolt length. Also decreased bearing wheel axle from 26mm to 24mm so bolt head can properly squeeze against bearing. Also added a 12mm diameter press area for bearing on bearing wheels. Increased LED hole sizes on Base from 10mm to 10.3mm as hole was slightly too small for the LEDs.

29/04/2024 V1.2: Flipped bolt head holes on B2B_A from bottom side to top to allow the bearing to be pressed more effectively. Added switch holder for microlimit switches. Increased LED holes from 10.3mm to 11mm.

01/07/2024 V1.3: Added m3 holes to outside of the switch holder to screw the switches down in the box in case the rats try to pull up the switch holder; this involved increasing the overlap from 5mm to 7mm. Increased height of base from 50mm to 60mm to go over the batteries as the connectors were thicker than expected. Also added a mount for the dual motor controller so it doesn't flop around in the base.

09/07/2024 V1.4: Replaced indicator embosses on the base with holes for 5mm Yellow LEDs on the base. Also added a different mounting position for the batteries in case 4 motors are used instead of just 2. Added tread to motor and bearing wheels as the previous versions were too slick for shiny surfaces.

29/09/2024 V1.5: Increasing spacing between switches on switch holder from 15mm to 25mm. Added spades for switches as ratties were struggling to step on the switches with their little feet.

13/10/2024 V1.6: Redesigned switch holder to use m4 used for attaching the rat box to the main body of the car as the m3 screws and new pedals stopped the switches from decompressing fully. Increased width of forward pedal from 25mm to 40mm and the width of the left/right pedal from 25mm to 40mm. Updated cutout template.

22/10/2024 V1.7: Increased pedal heights from 20mm to 38mm. Decreased left-right pedal width from 40mm to 35mm to clear bolt heads.