This lesson only applies to users with the Power Base or Developers Kit. Revolution Robots have a 7.4v LiPo battery pre-installed within the body.
Developer Kit Users
If you have a developer kit and the EZ-B is disconnecting, chances are that the batteries are not providing enough current for the servos. When this happens, it is called a "Brown Out". That means the EZ-B controller is not getting enough power when the servos move. In this case, the only solution is to replace the power source with higher amperage. A wall-wart (power adapter) will not provide enough current for electro-mechanical servo motors. The ideal option is to purchase a LiPo Battery, Balance Charger, and LiPo Battery Harness.
If you're convinced to use an adapter for power, there are also 2 great tutorials created by EZ-Robot users HERE and HERE.
Unregulated Power I/O
The EZ-B v4 does not regulate the power on the I/O pins. This means that if you provide 12v to the EZ-B v4, the I/O pins will output 12v. Of course, this will damage any +5v peripherals that you connect to the EZ-B v4 when using 12v. You must be aware of how much power is being provided to the EZ-B v4 and what you are connecting to the I/O pins. For example, the EZ-Robot Servos do not like power above 7.4 volts - which is why we recommend using Rechargeable AA batteries in the provided holder. If you are wishing to use an alternate power source, please be aware of this message and select a voltage rating that works with your application.
*Note: The only ports that have regulated power are for the Camera, i2c and UART #0 Expansion.
The EZ-B v4 has a battery saver built-in, which prevents the batteries from being drained. When batteries are completely drained, they will never maintain a full charge again. The EZ-B v4 will shut down all servos and ports when the battery drops below 6.6 volts (default setting).
*Note: Do not disable the battery saver feature or your batteries will be damaged!
The battery monitor can be disabled or adjusted for custom applications. Never disable the battery monitor for LiPo applications. Always use the battery monitor for LiPo applications. If you wish to disable the battery monitor on a custom application, this can be configured in the Connection Control by pressing the Gear icon. The battery monitor status will be saved with your project.
Choosing an AC/DC Power Adapter
As you are aware from the warning above, the power provided to the I/O pins of the EZ-B v4 is direct current. This means the voltage you power to the EZ-B v4 is also outputted on the I/O pins. Selecting an AC/DC Power Adapter is a great idea if you are spending a lot of time working on the EZ-B v4 to save on battery usage. The recommended AC/DC Power Adapter has these features...
- Switching Power Supply
- DC 5-8 volt current output
- More than 5 amps
- Center Pin Positive (on connector)
The ideal option is to purchase a LiPo Battery
, Balance Charger
, and LiPo Battery Harness
If you're convinced to use an adapter for power, there are also 2 great tutorials created by EZ-Robot users HERE
Using Included Battery Holder
The EZ-B v4 developer kit includes a battery holder for 6 AA batteries. The developer kit battery holder is great for introduction experimentation of the developer kit, but does not provide enough current for a robot build. The ideal option is to purchase a LiPo Battery, Balance Charger, and LiPo Battery Harness.