“SixPotatoe is the most recent in a line of self-balancing robots. You can see the entire lineup here: http://twopotatoe.net/. This robot was created for its high performance but also to be easy to build. It is controlled by a standard Arduino processor and uses off-the-shelf components. Anyone with basic mechanical, electronic, and software skills should be able to build a robot that performs as well as the SixPotatoe shown in the YouTube video. .
Supplies:
Parts
Most of the parts are generally available and some can probably be found locally. The only components that have only one source are the motors from Servo City and the motor controllers from Pololu. Almost everything else can be purchased on line from places like Amazon or Sparkfun.
Printed Circuit Board (PCB). This must be ordered from a manufacturer. The instructions for step 1 explain how to do this. For people with the necessary skills, it is entirely possible to build SixPotatoe using a breadboard or prototyping board.
Motor Controllers(2) from Pololu. I use the 24v13 controllers but the 24v21 will work as well.
5V Regulator from Pololu.
Planetary gear motors(2) with encoders from ServoCity. SixPotatoe is pre-configured to handle four of these motors. These motors are described at the end of this section.
Encoder cables. If you are using the Yellow Jacket motors, you will need these cables (2). The HD motors already have cables attached.
6mm Clamping D hubs (2) from ServoCity.
6-32, 1/2” screws (8) to attach the clamping hubs to the base plate.
12mm Hex Wheel Mount (2) from ServoCity.
32mm Bore Bottom Tapped Clamping Mount(4) from ServoCity.
LIPO battery. I use a Turnigy 1200 mAh battery. Almost any six cell batteries will work. The battery should have XT60 connectors This battery will run for more than an hour before needing to be recharged. Larger batteries give more operating time but also give more weight at the top which helps climbing steep slopes and over rough ground. However, small batteries can give the same performance improvement if mounted high enough.
Lipo Battery Voltage Tester. These are handy to check the battery charge but not absolutely necessary. These are inexpensive and widely available. The type doesn’t matter. Just be sure that it will check a 6-cell battery.
XT60 connectors. You will need one male connector to mount on the PCB. You will probably need a male and female connector to make a small battery cable if your battery does not have a long enough cable.
16 AWG black and red battery wire. Almost any stranded 14-18 ga. wire will work although I have a strong preference for silicone wire which is available from Hobby King or Amazon.
Teensy 4.0 Arduino controller. These are available from a variety of sources including Sparkfun and PJRC.
Electrolytic capacitors for the motor controllers (2). I use 330uf from Pololu. Pololu recommend larger capacitors. A higher voltage would also be a good idea.
Dumborc 6 channel RC receiver and transmitter. This is an inexpensive but very capable controller also available Ebay, Bangood, and AliExpress. This Instructable is designed around this controller although other controllers would probably work with a little modification. For any other receivers, be sure that the it will operate on 3.3V.
IMU from Sparkfun. This is an ICM-20948 mounted on a breakout with a Qwiic connector. The Qwiic connector can be used to add other sensors at a later point.
HDPE sheets. Other material can probably be used such as Phenolic sheets, alumunum or even baltic birch plywood. However, the frame needs to be very stiff, especially the base plate! I normally use 1/4” thick HDPE for both platforms although I often use 3/8” for the bumpers. For the bumpers, HPDE is probably the only suitable material because of its extreme durability. I buy my HPDE from the scrap bin of a local plastics fabricator but it is widely available from other sources.
Threaded rod to hold the platforms. I use M5 rods from Amazon but other sizes work just as well including M6, 10-32, 12-24, and 1/4”. You will need four lengths that will normally end up with a length of 120 to 160mm. The ones listed from Amazon are 130mm, which are a good size.
Wheels & Tires. I use Pro-Line F/R Masher 2.8” A/T Tires, but many other tires will work just fine. The wheel must have 12mm hex mounts, which is standard for 1/10 scale vehicles. Also, the wheel should have a “wide offset”. Any wheel that fits a 2wd Stampede®/Rustler® Front or 4x4 Stampede®/Rustler® Front and Rear should work. Even wheels with a narrow offset can be made to work by cutting away a bit of the base plate for tire clearance. The softer (more grippy) the rubber, the better. Also, the bigger the tire with more cushioning, the better. On the other hand, if you just plan on running on flat surfaces —- even grassy areas —- wheels like those from Bainbot work nicely.
LED Tactile Button. The PCB is designed to use this switch from Sparkfun. You may find it more convenient to mount a switch on the top plate. There are connection points on the PCB that makes it easy to hook up a cable to do this. For this, I like the LED switches from Adafruit.
Hardware for mounting the PCBs. There are a number of ways to do this and all of them work just fine. You should choose hardware based on what currently have or what is available locally. Read the description in Step 8: Mounting the PCBs to understand the options.
Mounting hardware for the PCBs. You should read the instructions in Step 8: Mounting the PCBs before deciding what parts to use.
Male Header
Female headers (2).
Schottky Diode (2).
Ceramic Capacitor 0.1uF
Electrolytic Capacitor 100uF
Qwiic cable.
Seven resistors: one each of 150 ohm, 470k ohm and 68k ohm and four 1k ohm resistors.
Lipo battery charger. I have no particular recommendations. There are many different ones available on-line and in hobby shops. The charger must be able to charge 6-cell batteries. A balancing charger is desirable but not absolutely necessary.
If you can’t find some of the miscellaneous electronic components locally or in your parts bin, they can be purchased from either Digikey.com or Mouser.com. Many of the small mechanical parts can be purchased at your local hardware store. If they don’t have exactly the part specified, you can usually find something similar there that will work just fine.
The total price for these components should be $400 - $500.
Before starting this project, you will probably want download and print out the mechanical drawings in the repository. These can be found in https://github.com/robertstuart/SixPotatoe-Instru… in the “Mechanical Drawings” directory.
Tools
Table or band saw to cut the platforms.
Drill. A drill press is nice but not absolutely necessary.
Saw to cut the bumpers. The bumpers could be omitted but this is not recommended. A jig saw, coping saw or even a router could be used to fashion the bumpers. I expect that those with good 3D printer skills could make something that would work quite well.
Soldering iron. A temperature controlled iron is recommended.
A vice of some type is needed to hold the parts while drilling or soldering.
A modest assortment of screwdrivers, wrenches, and pliers
Choosing a motor
The robot can use any of the following motors, available from Servo City. I have tried all of these motors and I have a slight preference for the HD 612 RPM but there are reasons, including availability, that you might want to choose another one. Note that there is an HD 1621 RPM motor available from ServoCity as well. I have had trouble getting it to perform correctly and have also had trouble with stripped gears, so it is not listed. Here is the complete list:
Yellow Jacket 435 RPM - This motor is a little cheaper, and a little less powerful that the equivalent HD motor described next. The encoders don’t have as much precision. Still, the differences would be hard to detect in most situations. Its top safe speed is around 15 KPH (9 MPH).
HD 437 RPM - For all practical purposes, this motor is equivalent to the Yellow Jacket 435 motor described above. It does have a teeny bit more power and better encoder precision, so it rare instances it will perform a little better. In fact, SixPotatoe was using this motor in many of the scenes in the YouTube videos.
HD 612 RPM - This is the ideal motor for many people. In fact, I delayed the publication of this Instructable until this motor became available again. Its top speed is around 21 KPH (14 MPH) and it manages jumps and rough ground with ease and is plenty fast. It is very stable and runs a long time on one battery charge.
Yellow Jacket 1150 RPM - This motor is just like the Yellow Jacket 435 RPM motor but is almost three times as fast. It won’t stay upright quite as well over rough ground and jumps, but the speed is very impressive. It is a lot of fun to drive. Its top safe speed is around 40 KPH (25 MPH). In my opinion, this is really faster than you will normally want to go. It can do considerable damage to itself, other things and people when it hits something at that speed. It will appear to be slightly unstable and out-of-control at its top speeds since it will bounce a little bit when encountering slight undulations in the surface. It consumes considerable battery power, especially over rough terrain and the motors will get slightly warm. SixPotatoe was using this motor for most of the high-speed scenes in the YouTube video.”