So before I even go into detail about my project. I just wanted to know what board is best for Ultrasonic Module HC-SR04 Distance Sensor For Arduino (http://www.amazon.com/gp/product/B004U8TOE6/ref=oh_o00_s00_i01_details). I ordered a UNO but it was cancel due to none in stock, so I have a chance to buy a better one if possible. I will also be using a motor with the chosen board. Pretty much I want the sensor to sense a specific distance and will get an input of 1 or 0. From that input it will send a signal to the board first and than the motor. I am not too good with this type of work, especially C/C++. Please help and I will take any advice or criticism!!!
You could use the sensor with every kind of arduino, there's not really a poor/better/best choice.
I wouldn't choose an arduino based on this sensor, but on the whole project, so please tell us more.
If you only would need a 4-8 KB program and 6 I/O pins, buying a board with 256KB of memory and 54 pins would be severe overkill. The Uno is quite nice in that respect, it has enough memory to even do quite advanced stuff and by itself it has enough I/O pins to handle all kinds of projects.
Im extremely sorry for not replying. I have too much things to do. I have no clue where to even start. As of now, I am just trying to write/use the sample code to test the board if its working. The sensor im using have 4 pins. What I want the sensor to do is sense a certain range of distance. i.e sensing 40-50 cm and anything below or above the 10 cm is consider high(1). I am trying to use this for stairs and walls for my baby walker.
For just the sensor and motor you wouldn't need a big board, an Uno would be fine and already oversized.
The sensor can measure distance with a good resolution from a short distance up to ~4-5 meters.
It shouldn't be to difficult to set a certain distance in software and stop the motor once it reaches it.
With a little bit of effort it's even possible to slow down the motor while approaching that distance.
One thing that may be quite difficult is measuring distance before going downstairs. The sensor won't notice it since there's no object to reflect the sound other than the wall that is much farther away. With multiple sensors you could aim one to the ground, but still, with some speed, that might be too late.
If a kid is operating the walker the routine to detect stairs needs a good foolproof solution.
Perhaps another sensor to, for example detect a beam of light mounted close to the stairs, might...
work. Problem is, it should always work, what if the light would fail ? Just reacting to light the walker might also stop driving outdoors.
Maybe other solutions could also work, for example checking for a line of magnets or RFID-tags on the floor. Problem is finding a 100% foolproof solution that is also practical to use. Stepping on magnets wouldn't be nice and what if they get loose ?
Although probably any arduino by itself has enough memory and pins to read and control the needed hardware attached and more, preventing the walker to drive downstairs will probably be quite a big issue.
Simplest would be installing a fence that is detectable by the sensor, but... I'd make sure it's also pretty strong. Should there be an unforeseen problem in your program, which also happens to me quite often, the walker still needs to be stopped.
Don't worry about the time it took you to respond, we're here for a hobby and I'm not always responding that fast too 