This page gives an overview about the required components and lists advantages and disadvantages for each of them.
Also included must be:
- prize
- power consumption
- size and weight
- possibly required modules or connectors for the micocontroller communication
- if nessecary: a circuit plan (created with Eagle)
Frame
Microcontroller
Raspberry Pi 2 Model B:
- a lot of existing projects and help
- only 40 GPIO Pins
- extension-board available (http://www.gertbot.com/) for real-time tasks and controlling of actors and sensors (easy to use with existing libraries)
- Price: Farnell £40.00
- size: width:130mm, height:15mm, depth:80mm
- weight: 0.25 kg
weight: 59g
size: heigth: 85 mm, width: 56 mm, depth: 17 mm
power consumption: http://raspi.tv/2015/raspberry-pi2-power-and-performance-measurement
Hardware:
- Prozessor: ARM710 with 900MHz
- RAM: 1024 MB
price:
Reichelt: 37,95 €
BeagleBone Black
In contrast to Raspberry Pi :
- better I/O capabilities with 7 channel 200kHz 12-bit ADC, 8 PWMs, 4 UARTs, quadrature encoder hardware
- don't have to buy additional components to connect up many more sensors and actuators
- large number of PWM channels on the Bones make them better for motors
- better real-time control with two 200MHz, 32-bit RISC programmable real-time units (PRUs)
- approximately 20 books available for texts, reference and projects
weight: 39.68 grams
size: heigth: 86 mm, width: 53 mm
power consumption: http://www.farnell.com/datasheets/1819364.pdf?COM=DesignCenter in section 6.1.7
Hardware:
Processor: AM335x 1GHz ARM® Cortex-A8
512MB DDR3 RAM
4GB 8-bit eMMC on-board flash storage
3D graphics accelerator
NEON floating-point accelerator
2x PRU 32-bit microcontrollers
Price:
Farnell element14: €46.16 (Price is before tax)
RS Components: £39.99
Battery
Motors
Gyro & Acceleration Sensors
Proximity Sensors
4-Pin Ultrasonic-Module HC-SR04
Links: Amazon, datasheet, short instructions
Cost: 6 x approx. 2€ ≈ 12€
Power Supply: +5VDV, 15mA working current
Pins: 2 GPIO, VCC, GND
- VCC = +5VDC (GPIO)
- Trig = Trigger input of Sensor (GPIO)
- Echo = Echo output of Sensor (GPIO)
Important: Outputs 5V. If the microcontroller can only handle 3.3V inputs, we need to build an easy voltage divider. - GND = GND (GPIO)
Minimum sensor recognition distance:
> Sensor’s minimum-distance does not have to be much smaller than 20cm (8“).
Infrared:
- Binary Output: detects whether an object is within a threshold distance
- Multiple Bit Output: detects the more or less accurate distance to an object
Pro:
- Quality products comparatively cheap
- In some cases very high resolution (up to 1 mm)
Contra:
- Problems with sun light
- Problems with recognition of dark or black objects
- Small range sizes
Recommendation after some research:
Sharp GP2Y 0A02 (ca. $11, 20cm – 150cm Range, Analogue Output)
http://acroname.com/products/SHARP-GP2Y0A02YK0F-IR-PACKAGE
(see also: http://acroname.com/articles/sharp-infrared-ranger-comparison for comparison)
Ultrasonic
Pro:
- Not depending on optical properties of an object -> more reliable in common usage
- Larger range sizes
Contra:
- Usually higher prize
- Lower resolution (2-3 cm)
- Problems detecting acoustic quieting objects
Recommendation after some research:
Parallax PING Ultrasonic Sensor (ca. $29, 2cm – 300cm Range)
https://www.parallax.com/product/28015
(maybe cheap replacement: http://www.dx.com/p/hc-sr04-ultrasonic-sensor-distance-measuring-module-133696?Utm_rid=37202148&Utm_source=affiliate#.VTsyqa3tmko)
Radio Telemetry Kit
Aukru HC-06 Wireless 4 Pins Bluetooth RF Transceiver Serial Module
Links: Amazon, instructions, instructions, instructions
Cost: 9€
Power Supply: 3.3V - 6V, approx. 50mA
Pins: 2 GPIO, VCC, GND
- VCC = +3.3VDC / +5VDC (GPIO)
- TXD = Trigger input of Sensor (RXD Digital 0)
- RXD = Echo output of Sensor (TXD Digital 1)
- GND = GND (GPIO)