The first demonstration will use the Capsela 1000 kit. This was a larger kit with 108 parts, marketed to build 100 projects, pretty much top of the line except for the remote control add-ons. The kit also includes a booklet "See how it works" in which Dr. Clifford Swartz demonstrated mechanical and electrical concepts using the Capsela pieces. Which is good, as some people (like me that are not natural mechanical prodigies) can learn what various combinations of gears can do.
What You'll Discover
- The motor comes in its own capsule and that can connect to the capsules that have gears in them. You need to consider what you are building to select the correct geared pieces in an order where the spinning will be done where you want it.
- The interconnections are mostly straightforward but not as flexible as Lego.
- For adding Crickit (without a tether), some sort of platform or flat space is ideal for mounting both Crickit and the battery pack.
Construction
For this build, I decided on a classic four-wheeled car type design.
The body has the following spheres (front to back):
- Transmission (straight through)
- Crown Gear or empty
- Worm Gear
The standard Capsela motor spins fast but does not produce much torque, which is required to move some weight. The worm gear capsule provides enough force to the wheels to get the bot going, especially on carpeted surfaces. The worm gear slows the speed of the motor by a factor of 49:1 to gain the torque.
If you put other mechanical capsules in, they introduce more friction which drags the motor power down even more. Be sure to use the B button to get the motor to 100% for the best grip or just code the bot to start at 100%.
The chassis uses three spheres with long yellow braces on each side. The motor capsule is placed on the top rear connecting to the worm gear capsule at the bottom rear.
For the second deck, an empty capsule is mounted on front with a short yellow brace between them. The Capsela 1000 switch is connected to the brace forming a flat space between the motor and the front capsule. The battery is layered on with some double-sided tape then the Crickit on top.
The top view shows the stacking of pieces in the middle: the Capsela 1000 switch is used vertically as a base for the battery pack and Crickit.
Some double sided tape or Blu-Tack holds the battery pack on the switch and the Crickit on the battery pack in a stack. Your adhesive should probably be easy to remove but strong enough that the vibration of use does not shake Crickit off the bot.
For the front, the 3 volt battery pack is mounted to the front sphere and a short yellow crossbar. The Capsela light is mounted on top with an L connector. Wires are tucked into the empty capsule. If you plan to use the light for a long period consider the 1.5 light as the bulb doesn't like 3 volts for long periods of time. 1.5 volts will be dimmer but make the bulb last.
The original design had the green impeller placed on the front, giving the vehicle a Star Trek like appearance. That addition makes ground clearance lower and I found a misaligned sidewalk can stop the bot.
If you want the light to blink, you can change out a capsule for the Rotary Switch Capsule.
Detail of the back, the motor driver leads are connected to the two power leads on the Capsela motor. I used a couple of screws jammed in to the power connections make the alligator clip to motor connections easier.
It is more convenient to use two of the Capsela wires to connect to the motor and to use the alligator clips to connect to the end of the wires. In that case, you have to tuck the wires out of the way before using the bot, perhaps by wrapping them around the capsule joint.
Code
You can start MakeCode on PC, Mac, Linux, or Chromebook at https://makecode.adafruit.com/. Start a new project. In the groups of colored blocks, you will need to go down the list until you get to ADVANCED. Click it and then click EXTENSIONS. Click on the Crickit extension and you'll then have a new green block group named CRICKIT which has the Crickit blocks this project uses.
Create the following program in MakeCode. Save to disk. Plug your Circuit Playground Express into your computer via a known good USB cable. You should see a new flash drive pop up. Click the MakeCode Download button and save the code file to the new flash drive which is called CPLAYBOOT. If you don't see the flash drive, press the Circuit Playground Express reset button and see if it pops up now.
When the code (in the form of a .UF2 file) is placed on the CPLAYBOOT drive, the Circuit Playground Express reboots and runs your code. You'll know when the code is running as a rainbow pattern is displayed on the Circuit Playground Express NeoPixel LEDs.
Use
Looking at the code, you can see several ways to alter the bot's functions. The slide switch on Circuit Playground Express (not the on/off on Crickit!) switches the direction the wheels turn. The A Button speeds up the motor, the B button slows the motor down.
You'll need to pick the bot up to change parameters, then put it back down. When Crickit is available with a microcontroller that allows radio control, it would be great to change things to use radio commands.
Page last edited March 08, 2024
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