Gertduino vs Gertboard vs Motor Controller

The main things you need is a solderless prototyping breadboard -  WBU-301J - WISHER - BREAD BOARD, PROTO TYPE 84MM X | Farnell UK  https://learn.sparkfun.com/tutorials/how-to-use-a-breadboard - some jumper wires - http://uk.farnell.com/wisher/wjw60b/jumper-wire-kit/dp/1173677 - and a set of resistors, potentiometers,  transistors, leds and push buttons (1).

I will go for motors, and other actuators once you get some kind of project in your mind.

You may think, "with that I won't be controlling 'real world things'", and you will be right.

But for a starter you just need to get inputs, compute them and generate outputs. Right now those inputs would be a push button - digital input - or potentiometer - analog input - and outputs would just be a led. But the main principle is the same if the input is a push button, a door contact, a LDR - light-dependent resistor - ,  a temperature sensor, or a neurosky chip hooked to your brain - not kidding, I get those from mattel Mind Flex games but they just hook to your ear lobe ;-).

The same with the output, you will be blinking a led, but you would trigger a relay to start a high voltage device, give a signal to a stepper motor controller,  send a signal to a DC motor controller to start running, or blinking a IR led to turn on/off your TV or HVAC.

You may be looking at analog inputs - LDR, potentiometers - digital inputs - pushbuttons - and how to get those inputs to produce an output - blink a led, trigger a transistor to start up another device.

I will also advice, if you have little experience, to grab an Arduino. Those are sturdy and there is a huge ecosystem to get started.

It also works with 5 volts instead of the 3.3 volts of the Pi. Most hobbist sensors are 5V and interfacing with the Pi may be a pain at start. Even worse if you think the GPIOs on the Pi are not protected so if you plug them to 5V you may fry you Pi.

You can then jump to a teensy 3.0 that's a device with an arm processor and 3.3V like the Pi but where your arduino code will work. You can look into the teensy code to start to understand arm processors.

Then jump to the Raspberry Pi through the arduPi library, taking advantage of the huge amount of Arduino examples around. It's the same API than the arduino but working on the Raspberry. You may even use the some of the same shields through a connector made by the arduPi authors. You can look at the arduPi code to start to understand the Raspberry GPIOs.

Or go for the GertDuino, that's a mix up between raspberry and arduino - it really is a raspberry with an arduino on top.

If you'd rather work directly with the Pi, it's good to get something that makes easy to hook up the Pi GPIOs to the breadboard. I use both the Adafruit adapter 914 - ADAFRUIT INDUSTRIES - PI COBBLER BREAKOUT KIT, RASPBERRY | Farnell UKhttp://learn.adafruit.com/adafruit-pi-cobbler-kit/,and the cooking hacks connection bridge Cooking Hacks - Documentation - Raspberry Pi to Arduino shields connection bridge

The Adafruit one is my recommendation if you don't have - or plan to use - arduino shields.

So my advice. Don't expend money on shields and controllers. Just get some basic components and try to learn to manage the basic stuff. Get inputs, process them, set outputs. A breadboard, wire, a connector and basic components will get you running. After that, to hook up "real devices" is easy. My only advice is if you don't feel too comfortable - or don't know how to - hook wires in your Raspberry Pi get an cheap arduino and fry it instead of your raspberry. Later on, go ahead with your Raspberry and discard the Arduino.

Happy hacking :-)

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(1) Example Kit with pots, leds, etc ... for the Pi (includes the connector for arduino shield mentioned): Starter Kit for Raspberry Pi

Same kind of kit for the Arduino - A000010 - ARDUINO - WORKSHOP KIT, WITH ARDUINO BOARD | Farnell UK

Kit with only the components - http://www.cooking-hacks.com/shop/arduino/starter-kits/cooking-hacks-components-kit-beginner-edition?_bksrc=item2item&_bkloc=product

Note: those are just examples, to take a component list from those kits and walk with it to your local electronics store - or just buy them all from Farnell - is highly recommended. Those kits use to be quite expensive if you compare them with the individual component's price.

Other links related to this post:

ArduPi library - Cooking Hacks - Documentation - Raspberry Pi to Arduino shields connection bridge

Teensy 3.0 ARM development board with Arduino API - PJRC Store

The main things you need is a solderless prototyping breadboard -  WBU-301J - WISHER - BREAD BOARD, PROTO TYPE 84MM X | Farnell UK  https://learn.sparkfun.com/tutorials/how-to-use-a-breadboard - some jumper wires - http://uk.farnell.com/wisher/wjw60b/jumper-wire-kit/dp/1173677 - and a set of resistors, potentiometers,  transistors, leds and push buttons (1).

I will go for motors, and other actuators once you get some kind of project in your mind.

You may think, "with that I won't be controlling 'real world things'", and you will be right.

But for a starter you just need to get inputs, compute them and generate outputs. Right now those inputs would be a push button - digital input - or potentiometer - analog input - and outputs would just be a led. But the main principle is the same if the input is a push button, a door contact, a LDR - light-dependent resistor - ,  a temperature sensor, or a neurosky chip hooked to your brain - not kidding, I get those from mattel Mind Flex games but they just hook to your ear lobe ;-).

The same with the output, you will be blinking a led, but you would trigger a relay to start a high voltage device, give a signal to a stepper motor controller,  send a signal to a DC motor controller to start running, or blinking a IR led to turn on/off your TV or HVAC.

You may be looking at analog inputs - LDR, potentiometers - digital inputs - pushbuttons - and how to get those inputs to produce an output - blink a led, trigger a transistor to start up another device.

I will also advice, if you have little experience, to grab an Arduino. Those are sturdy and there is a huge ecosystem to get started.

It also works with 5 volts instead of the 3.3 volts of the Pi. Most hobbist sensors are 5V and interfacing with the Pi may be a pain at start. Even worse if you think the GPIOs on the Pi are not protected so if you plug them to 5V you may fry you Pi.

You can then jump to a teensy 3.0 that's a device with an arm processor and 3.3V like the Pi but where your arduino code will work. You can look into the teensy code to start to understand arm processors.

Then jump to the Raspberry Pi through the arduPi library, taking advantage of the huge amount of Arduino examples around. It's the same API than the arduino but working on the Raspberry. You may even use the some of the same shields through a connector made by the arduPi authors. You can look at the arduPi code to start to understand the Raspberry GPIOs.

Or go for the GertDuino, that's a mix up between raspberry and arduino - it really is a raspberry with an arduino on top.

If you'd rather work directly with the Pi, it's good to get something that makes easy to hook up the Pi GPIOs to the breadboard. I use both the Adafruit adapter 914 - ADAFRUIT INDUSTRIES - PI COBBLER BREAKOUT KIT, RASPBERRY | Farnell UKhttp://learn.adafruit.com/adafruit-pi-cobbler-kit/,and the cooking hacks connection bridge Cooking Hacks - Documentation - Raspberry Pi to Arduino shields connection bridge

The Adafruit one is my recommendation if you don't have - or plan to use - arduino shields.

So my advice. Don't expend money on shields and controllers. Just get some basic components and try to learn to manage the basic stuff. Get inputs, process them, set outputs. A breadboard, wire, a connector and basic components will get you running. After that, to hook up "real devices" is easy. My only advice is if you don't feel too comfortable - or don't know how to - hook wires in your Raspberry Pi get an cheap arduino and fry it instead of your raspberry. Later on, go ahead with your Raspberry and discard the Arduino.

Happy hacking :-)

----

(1) Example Kit with pots, leds, etc ... for the Pi (includes the connector for arduino shield mentioned): Starter Kit for Raspberry Pi

Same kind of kit for the Arduino - A000010 - ARDUINO - WORKSHOP KIT, WITH ARDUINO BOARD | Farnell UK

Kit with only the components - http://www.cooking-hacks.com/shop/arduino/starter-kits/cooking-hacks-components-kit-beginner-edition?_bksrc=item2item&_bkloc=product

Note: those are just examples, to take a component list from those kits and walk with it to your local electronics store - or just buy them all from Farnell - is highly recommended. Those kits use to be quite expensive if you compare them with the individual component's price.

Other links related to this post:

ArduPi library - Cooking Hacks - Documentation - Raspberry Pi to Arduino shields connection bridge

Teensy 3.0 ARM development board with Arduino API - PJRC Store