Guys, just checking one thing. I'm using Analog A1 Pin to check for 5 buttons in series. What I did is used the A1 Pull-up-Resistor (digitalWrite(A1, HIGH)) and added the 5 buttons to the A1, while using a 10k resistor (or 220, don't remember which one) for each button, in series.
It works perfectly, each button outputs an unique value.
BUT, I want to know if this is OK to do. 
Thanks, Wk
Well if it works it works. Input pins whether digital or analog are high impedance inputs so no current to speak of can flow from or to them, so there is no risk to damage, unless applying an external voltage higher then Vcc, +5vdc or +3.3vdc depending on the model board you have. Now pins set to output mode, that is a different story and one does need to be aware of the current limitations when using outputs.
Lefty
Oh, bad news, it doesn't work. As soon as I light up a few more leds on my design, the numbers drop down. And yes, I'm using an external power-adaptor.
So I will have to find another way...
check for 5 buttons in series.
Unusual combination, you have to have all button pressed to get anything.
If you just want five independant buttons on one analogue pin this has been covered many times on the forum and is easy to do.
Otherwise post your circuit.
Rob
Thanks guys, I just found this out:
And since I know a bit of Spanish...
Wk
Thanks,
Interesting and elegant variation, especially as it can be easily extended to even more keys. It is easy to see that when one key is pressed there is an unique voltage. Two keys pressed can sometimes be detected, but not allways e.g. p5 and p6 are symmetric - changing the upper 5 resistors to another value could make this detectable. This rises the question can this schema be extended so that double key press can be detected?
I just used that design and it solved all my problems. Lucky me I did have exact 3.3k resistors. Also, I managed to get only 6 keys, by reducing the number of keys on each "side". 4 resistors for the 3 keys towards 5V, and 4 resistors for 3 keys towards Ground.
I don't need double keys, only single keys pressed. I will use an extra pin for my Shift key.
All in all, my project will use 80% of the pins. I will make an Youtube video soon... (LCD 16x2, 16 individual buttons thanks to a shift-register chip, 16 LED outputs also thanks to a shift-register chip, 7 navigation buttons, extra EEPROM 1 wire (uses 2 I/Os) Midi Input and Midi Output. http://open.wusik.com
Thanks for everything, you actually helped me out, as thanks to your comments I was able to find the correct thread and the solution above.
Best Regards, WilliamK
In case anyone wonders, here's the project with YouTube video...