Another option might be
to hack a couple of cheap servos for continuos rotation and dispense with the motor shield or arduino board with motor driver and just use the standard board. Then it becomes 2 tutorials in one and more tags???
Good points, thanks.However,
Good points, thanks.
However, “special board”, is that not part of the Arduino world? Who can list me all the boards there are available? (Apart from the “originals”)
Would it not be cool to say "Here is a “starter board” that has all you need to get started? Then later, you can add shields. What if the start-board is shield compatible?
I totally agre that the board should be “standard”, and not made for this start here-project. A VERY important factor of my tutorial is, that this is “real parts”. If I just wanted people to make a robot, then sell them a kit! Or some Lego!
But I think that these boards are becomming “standard”, and that they do live up to a “real dive into the world of making robots”. Do you not agree?
My point is; These boards are being used by other members, so I would say that they are as good as any, and not “special”, and not “kits”, this is the real thing, no?
Nono, this is win beacuse
Nono, this is win beacuse everything is kept simple as possible!
These tutorials are the stepping stone through “just all you need to get to know all the basics”, and I’d say that start hacking servos for someone who has never as much as made an LED blink before would be guiding to a wrong path, would you not agree?
We need to teach people how to hook up a motor, and possibly a servo. But not hacking servos, that is lesson 2, I’d say.
But still… good input, thanks a bunch 
Have you considered a crawler?
This would eliminate the need for wheels. What I’m thinking of is a pair of servo’s to lift the front of a platform and move it left or right and another two (mounted at 90 degrees to those to go forward or backward. It would be a very simple to assemble and be cheap. In fact I bet you could simplify it down to two servos and a belly for balance.
…pickle
You make a good point.
You make a good point. Besides, keeping it generic Arduino also is a good segue into designing “soft” components. For example, if I figure out that I need to adjust my course 40 degrees, I don’t adjust a servo right there, I call into my motor code and tell it to bear right. I like using an ESC and servos. Changing to using a motor controller would not be a nightmare, though.
I spend a lot more time figuring out the states to transition from/to and how to monitor everything in the loop than I do worrying about how particular bits of hardware need to be interfaced to. There are a handful of detailed operations - deciding how to interface using the pins (it’s all about the pins; this needs to be understood conceptually), using a hard or soft serial port, communicating with I2C devices using the wire library, generating PWM output and a couple of major concepts - getting everything set up and running as a state machine in a loop - that are key to getting comfortable and knowing how to go find out how to do almost anything with it. I would want to be careful about giving new users the impression that the way you run motors is with a particular shield, component or technique.
I’m not sure I quite
I’m not sure I quite understand you, so let me ask you:
So… What would you do then?
Thanks.
Then I would definitely go
Then I would definitely go for the Motorino, just to keep it in the family so to speak
Probably not the most famous out there but fits you project perfectly and still has the Arduino headers to work with.
The idea of another "type"
The idea of another “type” of robot than the one we know from the present “SH-bot”, is OK to me.
However, it is not made as it is by random. It is carefully considered to give the complete newbee an understanding of sensors, servos, motors programming etc.
If I where to scale down on something, it would be servos. because wunning a motor is so fundemental, that IMHO I would consider turning a servo step 2 - if these things had to be devided, and one thing thought before the other.
However, this time I will start by blinking an LED, not reading distance as I did last time. Possibly also making a sound before moving on So there will be diferences, but I do not think motors are cut away, but servos might be, time will tell
So, considering that running
So, considering that running a motor is so critical, would not a shield dedicated to that purpose be more informative to the new builder? Having the motor controller on the same pcb as the micro controller may hide the fact that we need a circuit to support an external device (like a motor). Servos simply have this circuit in the package.
…pickle
That is a tough question,
That is a tough question, but Geir made a point that gave me pause - if you want to do Arduino, why not start with a “standard” Arduino? I guess the UNO is more or less the standard entry model right now. The problem is that the Arduino is an easily extensible general purpose micro-controller, not specifically geared toward robotics unless you go with a variant. I guess you could start with that, develop the logic to decide where to move to (what is your plan for that?) or at least in what direction and then present some possible alternatives and choose a reasonable for the purposes of the tutorial. I would be willing to add some code to show how to do the higher end RC stuff; I have a truck chassis that will show up in a few days that I will be controlling with an Arduino. It has a servo for steering and an ESC to control the drive wheels. I will also be adding a range finder. This is a personal project and I can share the base code.
In case it isn’t clear, I
In case it isn’t clear, I mean I am offering to do what would be a sidebar of sorts - “here is how you can make a robot that can catch air when it goes over bumps” - with an agrred upon interface to the motor functions like forward, bearLeft, turnLeft, bearRight, turnRight and stopMotor that take speeds as parameters. I would also share main loop code that checks intervals since the last command was issued so you can time out instead of disappearing over the horizon.
I say stick with the Arduino
I say stick with the Arduino Uno because it is the standard. Even the start here robot is not that easy. There might be some soldering involved or something but nothing too hard. Give them an Uno and a motor driver breakout board:
That would be gr8
That would be gr8
a little more teaser info
Here is a link to a page someone did on a truck that uses the chassis I just bought, except the one I got has a motor upgrade:
http://koti.mbnet.fi/~oju/rc/Tracker2eng.html
should be insanely good fun. One concern I have is whether a 4.5 m range finder will let me do much more than brace for impact…
Seriously, I will probably run it at slower speed for autonomous operations or go to a really large open field for testing. But the basics of servo steering and ESC drive control are the same on nearly all surface vehicles.
I agree with the uBotino V2
I agree with the uBotino V2 kit, that would be the best for a start here robot. In my opinion cost is one of the key aspects, and the uBotino is already cheaper than the arduino uno without having to buy a motor shield as well. Not only that but you would gain valuable experience of soldering from the kit. However using an FTDI cable looks like a disadvantage and not being compatible with any shields could also get annoying - although I’ve never once used shields, they’re always too expensive…
It would be good if LMR made their own arduino compatible board, but I guess that would cost too much ?
I think FTDI is an advantage.
Where’s the love for FTDI? You can put your board in a tight fitting case and don’t have to get at the card edge. Once you have the cable, you can use it to do serial breakout from the USB to test things:
On the board it makes it easy to share the serial port with the IDE by using a male 6 pin header on the main board and female 6 pin headers on FTDI ready modules like Open Log (SD data logger), BlueTooth Mate, etc. And more importantly for a tutorial, it makes it much easier to explain serial data interfacing.
Good points, and I have to
Good points, and I have to admit that I have never used FTDI cables before, just a normal USB cable. But from what I can see, isn’t it easy to plug it in the wrong way round or bend the pin headers ? Surely a USB cable is more beginner friendly ?
If needed I can replace the
If needed I can replace the standard FTDI connector with a polarized one like this:
and also include in the package the mating connector housing and crimp pins. I can also offer the Prolific USB-serial cable already fitted with a polarized connector. The advantage of this polarized connector design is that you can always plug in a regular connector without damaging the polarizing tab. I'll try to make the price for a uBotino + USB-serial cable to $35, which is a better price than the Arduino because it includes the h-bridge. An Arduino + Motor shield will cost you a little over $40.
You may want to take into consideration that a 12 servo board called uServotino is on my way for testing. Similar form factor like the uBotino, but designed to be used with servos. One can use it for multi servo robots or for a rolling robot that uses continuous rotation servos for driving. Easy to swap in place of the uBotino and it will be cheaper as it does not include the h-bridge.
Anyway, people who want to build just a simple robot may use a dedicated robot controller. People that want to develop further, is best to stick with a form factor compatible with the shields.
** I am a little confused**
I am a little confused about the servo situation. Is it just increasing the number you can run? To run a servo on the Arduino, I use a PWM pin. And some wire. Power can be an issue if you have a bunch or overdrive even just a single small one (DAMHIKT ).
I am currently only using a couple of shields (but only 2 of my 5 Arduinos can even use shields) - a stackable prototyping shield on both my “standard form (plus - they are MEGAs)” Arduinos and an LCD shield stacked on top of one because I am lazy and did not want to figure out a better way to mount the LCD (just set the whole stack in a clear case and I am done). The prototyping shields are just a place to solder stuff after I got it working on the breadboard so it won’t come flying off in use. I think the primary audience for using shields is tinkerers who will make something, take it apart and make something else and keep reusing the boards for various purposes. A lot of them are not stackable, so it does not offer ultimate flexibility.
Anyway, at this point I am thinking that maybe I should just sit back and watch where this goes and just do a blog or tip or whatever on using ESCs and servos with PWM.
yeah good point
I’ve never used continuous rotate servos myself before and after I suggested that I thought hang on do they even still operate like a normal servo with the pulses. And I guess if one buys them for the starter bot it brings the price to around the same as if you use dc motors and motor shield. Ah well it was worth a try.