Questions about Arduino

Hey

I'm new to Arduino, Microcontrollers and electronics generally.
However, I participated in ROV local competition and just began to think about how we will control it.

We need to control many DC motors and it would be underwater !
I don't know anything about PIC micro-controllers, and I heard about Arduino and that it is so easy so I brought a brief book (186 pages) and read it in one day !!
I trained myself on Proteus and I loved the easy code and concepts of using Arduino.

Now, I want to buy a real Arduino board to train myself better and to test our work in the ROV competition and use it later in our ROV.

So, I have many questions by now :

1- Which is better for my case, Arduino UNO or Arduino Leonardo ?

2- When testing my work on breadboard I connect the Arduino to my laptob using USB cable that transmits both power and signals, but when the board is implanted inside my project, how I connect power to it ? .. or Do I need to connect power or I just need to connect a 5V source to the 5V pin ? Well, does the board have to be wholly implanted or I can remove the ATmega chip and use it in a PCB ? .. if I can, what is power needed then ?

Well, by answering these few questions I think I'll have a clearer vision about using Arduino in my project.

Waiting for your answer

Home brew Arduino fed directly fed with 5V.

Since the Arduino Leonardo chip is surface mounted it makes the above a bit tricky....

Mounted on a Raspberry Pi

pluggy:
Home brew Arduino fed directly fed with 5V.

Ok .. that's good.

pluggy:
Since the Arduino Leonardo chip is surface mounted it makes the above a bit tricky....

Mounted on a Raspberry Pi

I didn't understand that !!

The chip in my home brew is mounted on stripboard, the chip is the same one used in most Deumilanove/Uno/numerous clones. The Leonardoi is surface mount and wouldn't fit, Surface mount is tricky on a small scale hobbyist level. At a push you can program the chip on a Uno, lever it out of the socket and stick in it your own board. Its just about practicalities.....

The other picture shows it mounted on what I designed it for : mounting on a Raspberry Pi. Raspberry Pi Documentation

eng_osama:
1- Which is better for my case, Arduino UNO or Arduino Leonardo ?

Compare and contrast the two on this website. The biggest difference that I've seen people use the Leonardo for is the ability to emulate an HID device. If the board isn't going to be plugged into the computer, I don't see much need for this.

2- When testing my work on breadboard I connect the Arduino to my laptob using USB cable that transmits both power and signals, but when the board is implanted inside my project, how I connect power to it ? .. or Do I need to connect power or I just need to connect a 5V source to the 5V pin ? Well, does the board have to be wholly implanted or I can remove the ATmega chip and use it in a PCB ? .. if I can, what is power needed then ?

You either need to connect 7-12v to the Vin, which will regulate it down to 5, or connect your own regulated source to the 5V pin, like from a wall wart or battery. It can be less than 5V, but the clock speed will suffer if you go small enough. Read the datasheet for the microcontroller on each board for the exact numbers.

You can also remove the microcontroller from the board and use it standalone (it would be pretty difficult to do with the Leonardo, however). Google Arduino standalone for more information on doing that.

pluggy:
The chip in my home brew is mounted on stripboard, the chip is the same one used in most Deumilanove/Uno/numerous clones. The Leonardoi is surface mount and wouldn't fit, Surface mount is tricky on a small scale hobbyist level. At a push you can program the chip on a Uno, lever it out of the socket and stick in it your own board. Its just about practicalities.....

The other picture shows it mounted on what I designed it for : mounting on a Raspberry Pi. Raspberry Pi Documentation

So .. simply you say that Leonardo chip cannot be extracted out of the board and be stuck in and programmed to my board for a beginner like me. And UNO is easier in that part because I can push it out of the Arduino board socket and then put it into where board I like .. isn't it ? .. ok that's comforting because I've already ordered a leonardo !! .. but by then, how can I know the right pins of the chip and connect them to the right elements in my circuit ?

Rasberry .. I see now .. so do you recommend me to change my order and buy an UNO ?

Depends on whether you want to pull the chip out of it or not......

I don't own a Leonardo, but I know they don't do an old school 28 pin chip in an old school 28 pin socket version. They used to do a SMD (surface mount) version of the arduino Uno, I don't know if its still available.

If you wanted to take a surface mount chip off a bourd it involves special kit and melting solder.......

I have around a dozen Arduinos including thiose I made myself, owning more than one is very useful, especially when it comes to burning bootloaders (google it) and trouble shooting. One of my dozen is an SMD clone, it has its uses but I can't take the chip off it......

pluggy .. Thanx a lot. But you talk professionally and I don't know anything yet about SMD clones or microcontrollers as I said before.

Arrch .. Thanx a lot .. this is a good answer I was waiting for.

Lesson one : The chip circled in Red on the Pi is surface mount (a SMD - Surface Mount Device). The chip circled in blue is what used to be standard many years ago - a through hole chip mounted in a socket which is soldered on the reverse side with the legs of the socket going through holes. They are relatively easy to mess around with a soldering iron and cheaply available stripboard or home made circuit boards. SMD needs specialist gear that a hobbyist isn't likely to have (or even afford). In a mass production environment, the SMD lends itself to automation and hence cheap to produce in quantity.

eng_osama:
Rasberry .. I see now .. so do you recommend me to change my order and buy an UNO ?

I would keep the Leonardo, they are good for prototyping. You can also use it (or the UNO for that matter) as a programmer to program standalone setups. So whenever you want to build a new project, rather than buying a whole new board, you can just buy the chip ($3-5) and program it on the breadboard. From there, you can put it on it's little board designed for the exact project. This signanficantly cheapens the use of Arduinos in permanent fixtures.

Which is better for my case, Arduino UNO or Arduino Leonardo ?

A 'no brainer'; The Leonardo is a significant upgrade from the Uno, including more pins. Here's the kicker: it costs less. Better for less, how often does that happen? Now that I think of it, perhaps, in the world of electronics, that might not be such a rare occurrence.

I can remove the ATmega chip and use it in a PCB ?

If you get the Uno and the ATMega MC is ia DIP(dual inline package), yes you can. If the Uno you get has the ATMega MC as a SMD(surface mounted device, you can't just pop it out and put it into another board. It could be removed and solderred into another board but it would be tricky and difficult and I think, pointless.

  • Scotty