I am a newbie and dont own any kit yet but I have decided that I want to start out with the Arduino as I am a C# programmer so the C language of the Arduino is like second nature to me!
I think I'm going to go for the Arduino Mega so I have plenty of connections and memory to work with. Problem is that I can seem to find any starter kits that come with the Mega - does anyone know of any out there? If not - is there a suggested shopping list of things I should be starting out with to practice on - if so, what do you suggest?
If anyone else has any 'start up' suggestions then please let me know. I have already gone to the 'start here' section and read loads of info on the Arduino.
Thanks in advance,
James
Just did a blog post on an
Just did a blog post on an Arduino Duemilanove.
It’s a pretty cool thing, but for a “kit” I only know of a Seeeduino Catalyst Pack that has a lot of things to experiment with. It’s got a lot of fiddly stuff, but not sure what you can build with it. AdaFruit has a Arduino Starter Pack, but out of stock now.
It would help to know what you want to do. You’re here on LetsMakeRobots, so I guess a robot might be in mind. Robotshop has an interesting robot rover kit for the Arduino. To that you’d need the Arduino and an h-bridge. Their complete version has some good stuff, and options to add things.
Basics to get is the Arduino (whichever flavor), a motor controller (one for each motor or a dual for just 2), some motors, some sensors, some resistors, some LEDs, some switches, some breadboards (solderless or otherwise), wires for the boards, some battery packs, and batteries (rechargable).
hi lol how conveniant. only
hi lol how conveniant. only yesterday i finished a tutorial on arduino bucket bot. its got plenty of room for expansion and it also has a variable speed motor controller. if you would like to do that, good on ya. i havent seen any starter kits for arduino and im not familiar with the Mega.
http://www.mindkits.co.nz/_product_47975/Arduino_Mobile_Robot_Builders_Kit
The mega is still brand new
The mega is still brand new so there may not be enough stock around that companies can sell as packs. Not to mention the mega will be a very popular upgrade path for people who already have an arduino so they wont need a USB cable etc.
Cool - I’ll check them
Cool - I’ll check them out. Can you recommend a good motor controller?
I hadent realised it was
I hadent realised it was that new. Good point on the upgrade path though.
That would depend on the
That would depend on the motors being controlled, but if you mean for the Robotshop platform, then it uses Solarbotics GM9 motors. These are rated at 5 volts with a possible stall current of 670 mA. These are the primary parameters to consider when looking for a motor controller, voltage and stall current. Robotshop pairs the GM9 motors with a Pololu Low Voltage Dual Serial controller, which is a good controller. I personally do not prefer to send serial commands to a motor driver but like direct control from the microcontroller. The h-bridge that use direct control is the Solarbotics Secret motor driver which you’d need one for each motor due to the way the circuit is laid out. The Solarbotics driver uses the L293D chip, which is a bipolar transitor chip, which would lose about 1.2 volts on the output to the motors, where the Pololu uses the better FET transistors delivering more power to the motors. There is also the Adafruit motor shield, which also uses a couple L293D to allow control of 4 motors. I think the Adafruit motor shield has a better pin routing than the regular motor shield. What I’d probably do is get the Adafruit shield.
With regards to the stall
With regards to the stall current (sorry I’m new to all this), is that when the motor stops you get a bit of current back from the motor, and thats when/why you need a 1 way diode?
Stall current is where the
Stall current is where the motor is stopped and it becomes a short between power and ground, no longer having the back emf from the magnetic field reducing the amount of current used by the device. If you stop the motor, it just acts as a big coil rather than an electromechanical power transfer device. It does have the max torque at this point, but as long as it stays, the most current possible passes through it (until driver or coil failure).
The back current mentioned is probably back emf, that is generated by the motor coils passing the magnets making an opposing voltage. And generally diodes are intended to be one way devices (except zeners). Their use in h-bridges is to provide a path for the current to dissipate from the motor coils. Coils have a tendancy to maintain the current flowing through them, so they can significantly raise the voltage across the coil to try to keep current flowing a particular direction. The diodes allow a recirculation path so this voltage build up does not occur and fry other nearby components.
Thanks for that robologist -
Thanks for that robologist - I really appreciate your advice/input!
