Racing Power Wheels Part 6: Motor Testing, Controller, and Sparks

So it's been a while since progress has been made on the Power Wheels Dune racer. I've been busy with school and it set me back on this project. Below is a video of some of the progress that was made last time.

      

It's not a really good video. It was mostly composed of videos that I recorded here and there and there were some parts that I didn't get to record.

But below is a picture of where I was at last time with all the electrical parts mounted on some diamond plating that was cut out to fit the back portion of the frame.

In the picture above you can see the 3 12V batteries being held down with some rubber straps. On the back side of the battery pack I have two eye bolts that are supporting the back side of the battery pack. On the front side of the battery pack, which can't be seen in the picture above, I have two L brackets supporting the front side of the battery pack.

You can see where I have mounted the motor controller. I may need to create some kind of barrier of some sort to prevent the wires from going towards the sprocket. Heading towards the front of the Power Wheels, the motor was placed in front of the controller. It took me some trial and error to decide where to place the motor to be able to install the chain.

In the end, I found that maybe I should have move the motor just a little closer to the axle sprocket. The reason for this is because when we installed the chain it was quite difficult. So I had the motor and the axle sprocket not fully bolted down to install the chain. Once installed, I bolted the axle sprocket to the sprocket hub and bolted the motor down. Once this was done, the chain was on pretty tight without any kind of slack. I believe it's too tight. So I may enlarge the mounting holes for the motor to have some play for adjustment and then bolt it down.

Here's another picture of the setup in the back without the plastic Power Wheels body. It is a much clearer picture and you better see the parts on the back.

Racing Power Wheels Part 5: The Rear Axle and Parts

So lately I've been working on the axle and drive system and I have received the motor controller that was ordered from TNC Scooters and now the motor works now. I'm in the processing of trying to return the two motor controllers I got from Monster Scooter Parts so they can test them and see if they are faulty or not.

So I have received the axle, sprocket for the axle, brake disk kit, some collars, keys, a sprocket hub, and the wheels and tires. Below is an image of the axle with its components without the wheels. 

In the picture above, from left to right, you can see a collar, the brake disk, the sprocket hub with the sprocket bolted onto it, and then finally another collar. I'll go into a little more detail on each part that I have received so far for the axle. 

Racing Power Wheels Part 4: Project Update on the Motor Kit and Batteries

           

So more progress has been made with the Boca Dune Racer project. Parts were ordered before and most of the parts have arrived. The first thing to arrive was the motor kit that was ordered from MonsterScooterParts.com. The motor kit was the 36V 1000W MY1020 motor with an universal controller and a hand throttle.

http://www.monsterscooterparts.com/trsc/rec-categories/motor/36-volt-1000-watt-motor-controller-throttle-kit-standard.html

Batteries were also ordered from Monster Scooter Parts, 12V 18Ah sealed lead-acid batteries.

So below is a picture of the controller from Monster Scooter Parts.

Racing Power Wheels Part 3: Selecting Sprocket Size and Calculating Speed

So in the previous post I decided to go with the WMS Tuck and Run #35 Sprokcet from BMIKarts.com. 

BMI Karts lets you have the choice of selecting the sprocket ranging from a 53 to a 75 tooth sprocket. The product description didn't provide the outside diameters for each different tooth sprocket. So I went online to look for a chart that displays the outside diameter for a #35 chain size sprocket for different numbers of teeth. I found this chart online from Azusa Engineering regarding sprocket diameters of #35 chain size sprockets at http://www.azusaeng.com/Sprockets/AzSDno35.pdf.

I also found another website that provided the same information at http://ablproducts.com/35-chain-sprocket.html. So a 53 tooth sprocket would be about 6.5" in diameter and the 75 tooth sprocket would give about a 9.17" diameter. So I can pick a sprocket in between these measurements. So If I decide to go with a 65 tooth sprocket, I'll have a sprocket with a diameter of about 8" (7.978"). I can use this number to help me in determining the speed of the Boca Dune Racer.

The 36V 1000W motor has rated speed of 3000rpm. The sprocket on the shaft of the motor is a 11 tooth 8mm 05T sprocket. I am not sure what the 05T means but I found the diameter of this sprocket at this website https://electricscooterparts.com/sprockets8mmchain.html. They list the OD of this sprocket as 1-1/4".

Racing Power Wheels Part 2: Axle, Rear Wheels, Brakes, and Sprockets

We're currently waiting for the motor and batteries to still arrive here at Boca Bearings.The motor I had first ordered, the 24 Volt 650 Watt motor kit, is currently out of stock at the time until March. So we quickly decided to select another motor kit. We decided to go with the 36V 1000W motor kit. http://www.monsterscooterparts.com/36-volt-1000-watt-motor-controller-throttle-kit-standard.html

This motor kit draws about the same amount of current as the 24V 650W motor kit. From the equation P = I*V, the 36V motor draws about 27.8 amps while the 24V motor was going to draw about 27.1 amps. So I expect similar run times except that the 36V motor will require 3 12V batteries to run it. So this changes the amount of what we have spent into the $500 limit. This kit runs for $179.99 and the batteries we have chosen was the 12V 18Ah batteries http://www.monsterscooterparts.com/gr12vo18amph.html. We had ordered 24V battery packs that was intended for the 24V motor kit. The 24V battery packs go for $109.99. So one and a half of those packs would go for about $165. Only half of the cost of the batteries goes towards the $500 limit. So right now we are currently at $262.50. So that gives us a less amount of money to go towards the rest of the build, $237.50. At the time of ordering, I forget to consider the increase of cost of the batteries. But I'll try to work with what I got.

In the meantime, research on axles was being done. For go karts, there are primarily 2 types of axles: a dead (fixed) axle and a live axle. For this project I will be going with a live axle. A dead axle is an axle where only one rear wheel will be driven by the motor. A live axle is an axle that will go from one rear wheel to the other. A dead axle might be cheaper to make instead of the live axle. For now, I will try to do this project with a live axle and see if I can maintain to be within the $500 budget. 

Axles
So there are many options out there to be able to make a live axle for a go kart or for this modified Power Wheels project. I am planning on just getting rid of the whole rear end of the power wheels and just keep the metal frame. I will keep the plastics that rest on top of the existing motors and figure out how to mount them on again later on. I will need to check underneath the plastics to see if there is any sort of metal connection between the two running square tubing going from the front to the back. If not, then I will need to either weld/bolt on an additional square tubing between the two square tubing running from the front to the back.

3D Printed Robotic Hand: Part 8--The Wiring Diagram of the Hand and Codes for Adafruit Servo Shield

So in this post I will be going over the wiring of the 3D printed Inmoov hand and include images of the wiring with the use of the program Fritzing since I did not really go into detail of how I wired the hand when using it without the Adafruit Servo shield. To me, Fritzing is a very useful program that includes many popular boards and components to be able to recreate a wiring layout. Again, this wiring is set up to be used without the Adafruit Servo shield. Doing this can help reduce costs of the project. I will also be covering the codes that I did use when I was trying to use the Adafruit Servo shield. 

The Wiring of the Inmoov Hand

So I did not really go into detail on how to wire the robotic hand. This wiring setup is meant to be used without the Servo shield from Adafruit. It will just rely on the use of the Servo library of the Arduino IDE. Using the Adafruit Servo shield will require a different wiring setup.

The above image is the wiring diagrm of the Inmoov hand. The five servos are powered by an external supply, the 4 AA batteries. The 4AA batteries should should supply enough power to the servos. The battery power supply is connected to the power rails that is found on the top of the breadboard. The ground of the batteries is connected to the blue rail while the power (positive) of the batteries is connected to the rail next to the red line on the breadboard. The blue rail is the ground rail while the red rail is the power rail.

Racing Power Wheels Part 1: The Dune Racer and Motor Kit Selection

The next project for Boca Bearings will be to make a regular Power Wheels into a Racing Power Wheels to participate in the Power Racing Series. The Power Racing Series is a series of races where teams race each other with power wheels that they have modified to go much faster than their stock speed. The series also includes an endurance race of 75 minutes. It's a series where people can learn new things and skills and to simply have fun.

For this project, we've searched Craigslist until we've found a Power Wheels that we thought was best for the project. A used Power Wheels was desired since we are going to mostly just keep the plastic covering of the Power Wheels and not use the stock motor or throttle. The Power Wheels we ended up going with is the Power Wheels Dune Racer.