I am experimenting with Arduino Duemilanove. I can (big deal!) display numbers following instructions that are there on web.I wish to have a program to input starting time for a digital clock initially. My (primitive) idea is to (i) display number between 0 to 24( or 0 to 60), (ii) increment and decrement being governed by two on/off switches and (iii) the third switch to confirm the number and move on. All this is being governed by the set up part of program and inputs given by switches.My question is:
Will I damage the board if I use 3.3 v or 5 v or 9/v power supply on the board itself for simulating/testing purposes? If it will not, it would reduce need of another source of power.
sureshparanjape

 

There should be some power sockets near Pin A0, (Ground, Vin, 3.3V, 5V). Read the pin descriptions on the Arduino website or any instructions that came with your board.

 

Power

The Arduino Duemilanove can be powered via the USB connection or with an external power supply. The power source is selected automatically.

External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector.

The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.

http://arduino.cc/en/Main/arduinoBoardDuemilanove

 

Many thanks for two Senior Members-GropherT and shetlii01 for their comments.
As part of understanding I have used 5v supply for reading voltage at an analog input using external POT.
I wish to use 5 v on board to give reading at Pin 13,12 or 11 HIGH or LOW, only one at a time, for using its reading in the program.I couldn't get the answer from Power description of the board. Is my doing above a legitimate action/procedure?May be the figure in the attached file will explain better than my writing.
sureshparanjape

 

Many thanks for two Senior Members-GropherT and shetlii01 for their comments.
As part of understanding I have used 5v supply for reading voltage at an analog input using external POT.
I wish to use 5 v on board to give reading at Pin 13,12 or 11 HIGH or LOW, only one at a time, for using its reading in the program.I couldn't get the answer from Power description of the board. Is my doing above a legitimate action/procedure?May be the figure in the attached file will explain better than my writing.
sureshparanjape

.bmp files are forbidden and do not display on this forum. You will have to post an image in a different format.

EDIT: Never mind, they finally displayed.

You cannot do a push-button like that. When the button is not pressed, you will not have a 0 volt, you will have a 'float' where a precise voltage is not connected to the pin.

Instead, do it like this to make sure 0 Volts is on a pin when no button is pressed, then 5 volts when a button is pressed...

 

Dear Senior member GopherT,
Many thanks for your quick reply.
I would start testing my programming skillconfused to use three push button inputs to set starting time to add to my other program to display clock.
Thanks again
sureshparanjape

 

Normally, a 10k ohm resistor is used for a switch circuit as shown in POST #5.

Also, search Google for "Debouncing a switch". You do not need additional circuitry, just some software techniques. I will let you search for the details on debounce. Ask more once you read about it.