I am lost and am loosing hope, because my thesis leader wont tell me much and I have nobody else to cunsult my problem with.
Can you please help? Where should i start?
Thank you very much
That seems reasonable enough. You can use a pair of digital I/O pins connected via a pair of resistors in series, and take your output from the junction between the two resistors. Size the resistors so that the maximum current flow at 5V is below 20mA.
Can you, please, be more specific?
As I said, I'm not much of a electro engineer.
Could you draw a scheme or explain a little bit more about it? I don't quite understand how do I create the 2,5V "zero" line and how do I modulate that signal to be biphasic.
Hi, biphasic, two phases.
What is the waveform of the other phase, and how is it related in time to the first.
Lets call them Phase A and Phase B.
Tom.....
[soapbox] Surely you must have tutors or lab technical staff to help you, did in my day of engineering, they would fall over backwards to help because that was their job. Especially on thesis.
Go and see your INSTRUMENTATION ELECTRONICS AND SENSORS lecturer or tutor. You would have been taught basic electronics there, PeterH solution is simple and neat, lookup or ASK your lecturer or tutor that you want to know about Potential Dividers and your problem. [/soapbox]
kakaovnik:
I don't quite understand how do I create the 2,5V "zero" line and how do I modulate that signal to be biphasic.
Think about the circuit I described and draw it out in your head or on paper.
Identify the junction between the two resistors which I'm proposing you use as the output.
Calculate the voltage between that point and ground when the two I/O pins are both high (5V), both low (0V) and one high/one low.
If you can't manage that then you ought to ask your tutor for more help because this is a very simple resistive circuit and if you're using electronics for your thesis this should be easy for you; if it isn't, you need to either do more studying or pick a different project.
Piece of cake. See this pinlabel on left side? It's should be connected to arduino digital pin, configured as INPUT. Now, you setting pot to 2.5V. Right side pin is output - to load. In static, cap is charged to 2.5V via resistor /or via load( if connected). When you set your arduino digital pin as OUTPUT and immediately write HIGH, than using delay you wait as long as you need positive pulse duration, after that you setting digitalWrite( bifase, LOW) and wait again to form a negative, and last step pinMode( bifase, INPUT). Condition: capacitor size must satisfy : C >> T / R, where T - pulse duration in sec, R - load resistor ( assuming R shown to ground at least 10x R-load and has negligible effect). Arduino can't drive less than 150 Ohm or so. Example, R-load = skin, or 1 kOhm, than R= 10k, pot 10k - doesn't matter, cap size if T= 100 millisec , C = 0.1 / 10^3 = 10^-4, or 100 uF. Use 1000 uF, to met >> (significantly).
Arduino seems great to use, because of its great ability to PWM, but I am lost in creating the other phase.
Pwm (alalogWrite()) would be difficult to use to get two signals that are out of phase (by a known amount). However take a good long hard look at the "blink with out delay" example and think (to start with) about how to get it to flash 2 leds that are out of phase by x degrees. But given the signal you want an aduino is over kill, look at opamp.
