Negative pulse generator with Arduino ????

Hello
Anyone knows if the arduino uno can produce negative pulse ???
Eg at 1khz
Anyone who knows us here to upload your code.
thanks

You can certainly output low-going pulses (5V -> 0V -> 5V) at about 1 kHz but you will need some external pulse shaping to get that funky shape. A capacitor can be used to round off the leading edge. A resistor will set how long it takes to reach zero. A diode will get the value back up to 5V quickly.

Are you trying to create negative voltages ?

The Arduino cannot do that directly, but there are ways it can be done , indirectly.

Here's the long and the short of it...

http://www.learningaboutelectronics.com/Articles/How-to-build-an-RC-type-differentiating-circuit

                          [color=blue][b]1N4148[/b][/color]
[b]Arduino Output Pin[/b]   [b]o[/b]———[color=blue][b]——|>|——[/b][/color]——?——————?—————[color=blue][/color]——[b]o[/b]   [b]Signal Output[/b]
                                                                                                                     [b] [color=blue]10 K?   0.01 ?F [/color][/b]
                                                                                                                        |       |
                                                                                                                       Gnd     Gnd

Calculated for 0.1 ms time constant: Online RC Time Constant Calculator - Gadget - Open Source Code

michinyon:
Are you trying to create negative voltages ?

The Arduino cannot do that directly, but there are ways it can be done , indirectly.

No negative voltages but negative pulse.
As the small photograph uploaded.

johnwasser:
You can certainly output low-going pulses (5V -> 0V -> 5V) at about 1 kHz but you will need some external pulse shaping to get that funky shape. A capacitor can be used to round off the leading edge. A resistor will set how long it takes to reach zero. A diode will get the value back up to 5V quickly.

Know a circuit that works properly?

No negative voltages but negative pulse

?

dlloyd:

                          [color=blue][b]1N4148[/b][/color]

Arduino Output Pin   o—————|>|————?——————?———————o   Signal Output
                                                                                                                    10 K?   0.01 ?F
                                                                                                                       |       |
                                                                                                                      Gnd     Gnd




Calculated for 0.1 ms time constant: http://hughestech.com/rc_calculator/

Would try it. thanks