I want to make the next generation of the "Start Here"-instructions be based on Arduino instead of Picaxe.
Some will say that it was about freakin time, but so far the advantage of the Picaxe has been that I could chose a single board that "did it all": Hook up Motors, Servos, sensors and everything.
This, and the fact that the Picaxe Basic Language needs very little introduction, made it the choise - even though the Arduino series has been a lot more popular recent years.
However, now there are such boards as The uBotino V2 Kit that does it all: You can connect servos and motors and sensors and all.
It is not that I mind the Arduino shields, it is a nice way of thinking IMHO, but for a start robot, I need AT LEAST motor control on the main board.
But it is a open source jungle out there, so I need your knowledge;
What other boards are there, that at least has motor control on the board, and even better if it can also control servos, and or other stuff? And has this board good community support, and can it be purchased assambled?
but I would like to try and modify a metaboard : http://metalab.at/wiki/Metaboard (I do not really like ftdi cables and the romeo board is a little expensive)
Yes, thanks a bunch konto89 - Groboduino and Romeo, I knew these, was just too occupied with looking around on Google, and forgetting that we have it all here
Thanks. I will have a cloder look at those.
And NOW I am interested in hearing if any one knows of similar that I have not heard of. Or forgotten
Yer… but this would not excactly make things super-fast to explain, or am I missing something?
I need to take people who hve NEVER touched any electronics or programming by the hand, and SIMPLY get them started with a robot. That extra library-fiddeling around, will not make it any easier, am I right?
BTW, I am using Arduinos without motor controllers; they generate PWM that you can feed to ESC units from higher end RC stuff.
I have a MEGA that controls a couple of motors, a couple of ganged servos, has a GPS, an LCD display, a tilt compensated compass, an SD ldata logger, an xBee RF transceiver plus a sonar unit should be dropped of by the brown truck tomorrow. It also has a bunch of simple buttons and sensors. The only shield I have on it is a prototype shield. The “shield per function” way of doing things is limiting. Serial and I2C devices give you plenty of functionality and come in small packages.
You can get a dual motor controller for under $10 from Pololu or SparkFun that uses a 2 digital pins and 1 analog (PWM) pin per motor if you want to run the gearbox stuff, but ESCs are the way to go if you want higher end motors.
I got one from Pololu and ran them through the wringer because it was not working. It ran the motor forward,but not backward and after a few test cycles not all in either direction. We finally figured out that the test code I was doing was reversing so quickly that the motor was still spinning. I thought I was being smart and using a really low power setup to do initial testing, but it was so weak it could not sink the feedback power from the spinning motor and it killed the motor controller.
For a complete beginner project, why not get a two motor RC tank and just use 2 transistors to switch the power off and on? Forward only,one motor at a time to turn or both at once to go forward.
I think having a single board such as the uBotino (you mentioned) that does everything you need is a great approach for beginners and simplicity in general. It would be nice if the board used a beefier H-bridge than the SN754410, such as an L298N which requires flyback diodes. Here is a link to an arduino motor sheild with the 298: http://www.sparkfun.com/products/9815
I also think the baby urangutan (328) would be a small, awesome platform (running the arduino environment if so inclined - http://www.pololu.com/docs/0J17) for a beginner, mini breadboard robot. I think if more peeps on here were supporting coding in C it might not be as scary to the newbies. Could even start a lets make robots AVR GCC library… #include <lmr.h>. Best of luck with start here v3, I’m sure it will be a winner.
I have been thinking of using a L298N h-bridge on the uBotino, but the board would have been larger. Then of course, the board was designed for small robots, most of them do not need more than 1A per motor. And even if they do, you only have to solder another SN754410 on top of the first one, but you also need to add a heat sink for them. This way you get the same amperage per motor as with the L298N but on a smaller board and without the need for external fly back diodes.
I’d like to know a heatsink part no that works with the SN754410 if anyone has one, I tried searching Mouser a while back without results. I had some f150 (I believe thats the part no) Tamiya motors that had too great a stall current for use with these low current H-bridges. Not fun when your first robot stops working after ~10 seconds because of thermal shutdown.
The extra library step would probably not make it much harder at all. Installing the Arduino IDE already means copying things around. The library is just copied in also. Someone who does more open source would know the GNU guidelines better, but I think you could grab the Arduino distribution, add in the library and then make it available here as long as it was clear that you are not claiming ownership or anything. Besides, nearly all Arduinos other than the “standard” line will have a library and/or sample code to be downloaded.
Having baked in motor controls would make it so much easier after the fact. But, I looked into it a bit further and while I find that a really attractive option (especially the Baby O at < $20!), it still has non-Arduino differences with pins and what not.
Have you done much with Arduino yet? I would hesitate to call it easy; it is easy to get code that doesn’t do much onto a board and run it. After that, the curve is steep and the water is deep. It can do everything because it starts out with nothing but loads of pins and an easy way to use them for digital or analog in or out with lots of code to help you do serial IO, I2C, PWM, etc. I love the Arduinos, but I am not sure they are anywhere close to the simplest way to get into this.
I might be getting too advanced again, but a Pro Mini is around $20 and for less than $20 you can get an import ESC with a BEC and motor. Servos you can get in the $5 range. So for around $50 you can get the guts for a higher end motion platform.
I haven’t looking too hard on a heat sink yet, but I remember I saw a board not long ago on LMR that had 4 SN754410 wired in parallel and all with a heat sink on them. I’ll try to find it and ask the maker where he got the heat sinks from.
My personal thoughts on this are if you’re going Arduino then just go Arduino. No special board for this particular robot. You’ll need a motor shield but that’s the way it is. As this is the entry point of many of us things tend to get recycled into other projects and then it’s great to have a regular project board and not a custom board that is optimized for the start here robot.
