Arduino vs Raspberry Pi - Decisions, Decisions

Arduino

• 16MHz 8-bit microcontroller
• 2 KB or more RAM
• 32 KB or more program storage
• 14 or more Digital Pins
• 5 or more Analog pins
• i2c, SPI, USB serial device
• Program in Processing, C or C++
• $30AU - or more, or less

Raspberry Pi

• 700MHz 32-bit microprocessor
• Up to 512MB RAM
• Gigabytes program storage
• 17 Digital Pins
• i2c, SPI, USB host ports
• Camera interface, HDMI, composite video, audio out, Ethernet
• Almost any programming language
• $28.50-$35AU

Microcontroller

Just runs your program
(Simplicity)

Microprocessor System On-A-Chip

Runs whole OS
(Power)

Headers

I/O Voltage

Raspberry Pi: 3.3V Logic

Arduino: 5V Logic

Analog Inputs

Arduino only!

Raspberry Pi

5V, fussy

Arduino

5V or 6-20V (varies), not fussy

Power Consumption

Arduino <100mA, Sleep Modes

Raspberry Pi <1000mA, No Sleep

Sources: http://www.ecrostech.com/Other/Resources/Dhrystone.htm
http://mobile.arm.com/products/processors/classic/arm11/arm1176.php
http://people.sc.fsu.edu/~%20jburkardt/m_src/linpack_bench/linpack_bench.html

Remote Access

Encryption

USB devices

Open Source?

Long term availability?

Timing

Soft vs Hard Realtime

Code Samples

                  
PIN=4
wiringpi2.pinMode(PIN,1)

while True:
    wiringpi2.digitalWrite(PIN, 1)
    wiringpi2.digitalWrite(PIN, 0)
                  
		

Head of the queue

                  
sudo chrt 99 ./python_toggle.py
                  
		

Better, worse, same?

C?

              
pinMode(PIN, OUTPUT);
while(1)
{
  digitalWrite(PIN, HIGH);
  digitalWrite(PIN, LOW);
}
              
            

4 MHz?

CONFIG_PREEMPT_RT ?

Arduino?

              
pinMode(PIN, OUTPUT);
while(1)
{
  digitalWrite(PIN, HIGH);
  digitalWrite(PIN, LOW);
}
              
            

              
cli(); // Turn off all interrupts

// Do your realtime thing here

sei(); // Turn back on all interrupts
              
            

So what to do?

• Match solution to problem
• Combine the two together
• UDOO
• Arduino Due & friends
• ChibiOS/RT on Pi
• BeagleBone Black w/ RTUs