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https://github.com/berndporr/alphabot
C++ API to control the functionality of a heavily customised Alphabot with a Raspberry PI
https://github.com/berndporr/alphabot
alphabot pwm robot robotics robotics-programming
Last synced: 22 days ago
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C++ API to control the functionality of a heavily customised Alphabot with a Raspberry PI
- Host: GitHub
- URL: https://github.com/berndporr/alphabot
- Owner: berndporr
- License: apache-2.0
- Created: 2021-04-03T10:03:05.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2022-07-07T22:05:49.000Z (over 2 years ago)
- Last Synced: 2024-11-11T04:32:57.948Z (3 months ago)
- Topics: alphabot, pwm, robot, robotics, robotics-programming
- Language: C++
- Homepage:
- Size: 580 KB
- Stars: 1
- Watchers: 2
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# C++ Alphabot API for the Raspberry PI
This page provides instructions how to customise the alphabot so that it's actually
usable for research and it provides a C++ API with proper setters and callbacks.
C++ class to control the basic functionality of a customised Alphabot
(https://www.waveshare.com/wiki/AlphaBot) with a Raspberry PI:
- Motor control (using the Parallax Continuous Rotation Servo)
- Distance sensor readings (digital and analogue)
- Battery voltage
- IR sensor readings
- 10Hz ADC sampling rate with callback
## Hardware mods
### Parallax Continuous Rotation Servos
Throw the original DC motors in the bin and fit the [Parallax Continuous Rotation Servo](https://www.parallax.com/product/parallax-continuous-rotation-servo/) with 90deg brackets. Plug them into the servo ports S1 and S2.
This corresponds to:
```
GPIO27 = Motor left
GPIO22 = Motor right
```
### Voltage regulator
De-solder the LM2596 and throw it in the bin. It supposed to have a dropout voltage of 1V so that the 7-7.2V from the battery
should be fine but it seems to be more 2V. It's not even recommended by TI who recommend the LMR33630 for new designs.
Replace the LM2596 with a [REC8-0505SRW/H3/A/M](https://onecall.farnell.com/recom-power/rec8-0505srw-h3-a-m/dc-dc-converter-5v-1-6a/dp/2846262). Just glue it upside down on the PCB and run 4 wires to Vin and +5V.
## Software prerequisites
### pigpio
The Raspberry PI hardware is accessed via the
`pigpio` library. Install its package:
```
apt-get install libpigpio-dev
```
### ncurses
The demo programs below display the sensor
readings with the ncurses library. Install
it with
```
apt-get install libncurses-dev
```
## Building
The built system is `cmake`. Just type:
```
cmake .
make
sudo make install
```
## Usage
The online documentation is here: https://berndporr.github.io/alphabot/
### Start/stop
Start the communication with the robot:
```
start()
```
Stop the communication:
```
stop()
```
### Motor speed
Setting the speeds of the left/right wheels:
```
setLeftWheelSpeed(float speed);
setRightWheelSpeed(float speed);
```
where speed is between -1 and +1.
### Get Collision sensor readings
The digital functions are boolean values which are true if the
distance sensor threshold (set with the potentiometer) has been reached:
```
bool getCollisionLeft();
bool getCollisionRight();
```
The analogue readings from the sensors from 0..1 can be read with:
```
float getLeftDistance()
float getRightDistance()
```
### Battery voltage
The function `getBatteryLevel()` provides the voltage of the battery
in volt.
### Infrared channels / general purpose ADC channels 0-4
```
float (&getIR())[nIR]
```
returns a reference to the whole array of IR sensor readings
normalised between 0..1.
### Callback
Whenever a new set of analogue readings is available the callback `step`
in `StepCallback` is called. It contains the reference to the Alphabot
class itself so that one can read the different ADC values.
## Demo programs
`testIO` is a simple test program which displays the different
senor readings and you can test the motors. It also shows
how the callback is used to display the sensor readings.
`testMotor` ramps up the motor speed and back again.
`obstacleAvoid.cpp` implements a Braitenberg vehicle
and it has an emergency stop if the digital readings from
the collision sensors are triggered. This is an
instructional example and needs to be tweaked. The
fun begins here! :)