Convert to a cyber:bot

The cyber:bot board is very similar to the Board of Education or Board of Education Shield.  It fits on top of the same small robot chassis.  It has 3-pin headers with selective voltage, and a 3-position switch for powering the breadboard circuits with or without powering the servos.

What is new is that this robot has more than one “brain.”  Your Python programs for a micro:bit mounted on the cyber:bot board will communicate with a  pre-programmed Propeller multicore microcontroller “assistant” on the bottom of the board.  The Propeller automatically controls the servo motors, interacts with sensor circuits, and replies back with data. 

For a more complete reference, see the cyber:bot board guide.

cyber:bot board guide

• Take a look at your cyber:bot board Rev C’s features before moving on.

Parts needed

• cyber:bot board Rev C (#32702)
• micro:bit module (v 1.5 or v 2)
• USB A to microB cable (#805-00016)

• Orient the micro:bit module so the LED display is facing upwards.
• Hold the micro:bit by its sides,  and slide gold edge of the micro:bit module into the edge connector on the cyber:bot board until it is firmly seated.

Preparing the chassis involves

1. Removing the current development board
2. Only if desired, changing the servo orienation
3. Upgrading to a 5-AA battery pack if needed

Remove the Current Board

• Unplug the servos and battery plug from your robot’s current development board.
• Remove the development board from the robot’s standoffs. Save the #4-40 pan-head screws and whisker-post hardware!

Servo Check

The cyber:bot robot uses the same Continuous Rotation Servos as the Boe-Bot and Shield-Bot.  You do not need to change the position of the servos!

The Boe-Bot and Shield-Bot instructions install the servos with the servo mounts inside the chassis, and with the servo cables pointing back towards the tail wheel. This is perfectly fine! You can keep them this way!

However, some images in this tutorial may show the servo mounts outside of the chassis, as shown below. This makes it easier to swap out servos if needed.

Other images may show the robot with the servo cables pointing towards the front of the robot. This makes it easy to re-center servos that have a potentiometer adjustment screw. However, this configuration’ wider wheel base makes it harder for the robot to make turns. If your robot servos are ports-backward, you can still adjust the poteniometers using a long, thin screwdriver, if needed.

•   If you want to re-install the servos to a different configuration, do that now.

Battery Pack Upgrade if Needed

The cyber:bot uses a 5-AA battery pack. If your robot has a 4-AA battery pack, follow the steps below to replace it.

• Remove the 4-AA battery pack and save the Nylon flat-head screws (if you have not done so already).
• Remove the screws holding the rear standoffs to the chassis.
• Insert the 5-AA battery pack. It takes a bit of maneuvering: slide the edge under the the tail wheel ball, level it out, then snap it into place.
• Insert the reserved Nylon flat-head screws, threading them through the battery pack case’s outermost holes.

• From the top of the chassis, thread a 1″ round standoff on each screw and tighten.
• Pull the battery pack’s power cord and servo lines through the rubber grommet hole in the center of the chassis. 

Parts needed:

(1) cyber:bot board with micro:bit installed, servos and battery pack unplugged!
(2) 1/4-inch pan-head screws
(2) 7/8-inch pan-head screws
(2) white Nylon washers
(2) 1/2-inch round aluminum spacers

• Rest the cyber:bot board on top of the chassis’ four standoffs. The white breadboard should be near the front of the cyber:bot, NOT over the tail wheel ball.
• Put a 1/4-inch screw through the each of the board’s rear mounting holes, and secure to the rear standoffs.
• Slip a white Nylon washer, and then a ½” metal spacer, over each of the 7/8-inch screws, and secure to the front standoffs.

• Make sure the white breadboard is above the flat front of the robot chassis, NOT over the tail wheel:

• Make the loose wires tidy by pulling the slack back into the bottom of the robot. A zip tie could hold them tightly, or you may press them between the servos and chassis.

Now, it is time to connect the servo cables to the cyber:bot board.  Then, you will set the servo ports’ power jumper, based on what kind of batteries you are using. But first:

• Unplug the battery pack from the cyber:bot board, if you have it plugged in!
• Put the power switch in position 0.

Connect the servos

• Plug the left servo cable onto the P18 port, and plug the right servo onto the P19 port.

Voltage Selection Jumper

There is a smaller 3- pin header to the left of the servo ports.  A shunt jumper connects two pins on it, selecting the voltage source supplied to the servos. The 5V setting limits the voltage to 5V, regardless of the input voltage.  The VIN setting supplies the servo with whatever voltage level is connected to the board.

The Continuous Rotation Servos need 4 to 6 VDC to operate. So, the setting you should use depends on the kind of batteries you have.

• 1.5V alkaline batteries: Use the 5V setting.  (1.5V x 5 batteries = 7.5V, which is too much.)
• 1.2V NiMH rechargeable batteries. Use the VIN setting. (1.2V x 5 batteries = 6V, which is just right)
• If needed, lift the shunt jumper off of the pins and place it back on again so it connects the center pin and the pin for the correct voltage for your type of batteries.

Add the Batteries – the last step!

• Plug the battery pack into the power jack on the cyber:bot board.
• Add the 5AA batteries to the battery pack.

Now you are ready to go to the next tutorial: Navigation with the cyber:bot.