There may be several reasons why your signal is not centered on the screen. It might have a DC offset in itself, or the input of the scope adds an unwanted offset. Given that the 1st video only shows a signal which seems to show the negative side of the waveform, I would say you’ve somehow added a positive offset to your signal which lifts the signal up to the top of the screen. Check whether R2 and R3 are connected properly and have the correct value. Those (together with RV1) should normally center the signal. Furthermore check that RV1 is grounded properly.
I finally got audio out from it. Turns out my cable its kinda dodgy. Hehe
When im not connect it to my speaker (only synth + oscilloscope )
The waveform looks more bigger, it satifying to look at, then if i connect it to speaker, it get smaller
Video :
And i still got dc offset issue
I look out on internet, i just add 100nf cap in input
The graphic waveform looks bigger than before, but its still not centered
I’ve checked my connection and ground and sure its all good
An AC signal in itself should look symmetrical around 0 Volts. If you add a DC offset, it will not anymore. The downward excursions (the display is shown upside down in the video) of the signal look like they are only half of the signal. Also the spacing between them looks like the positive half of the signal’s wave is ‘missing’, as if it is muted (or rectified). Another reason for seeing that could be that the scope’s center line (where it should show 0 Volts) is at the top of the screen. If you are using the latest version of the software, you should be able to adjust the offset so that the scopes center line will be shown lower on the screen (typically in the center of the screen). You could also try one of the AV settings, it will try to automatically set the appropriate voltage and center the 0 Volt mark to the center of the screen (this does not always work well, though). Let me know whether any of this helps.
The libraries you mention sound ok to me. You only need them to get the display going.
As long as that has a mid position in which it connects nothing, you are all right.
The led should always flash if you press one of the buttons. If it doesn’t then that button and its wiring need to be checked. You may want to start by checking the wiring of the diodes. The side with the circular line on it needs to be connected to the switch.
Fix the switches first and then experiment with the offset function (right most menu item). You won’t see much of an effect with small values. Use a large value of maybe 150 or -150
Which line code i need to change ?
I think im give up and quite happy without proper centered waves and non working button.
And when im messing around change the ground and input for one of my push button , i stuck on “voltage meter” display
The others button still didn’t work tho
Why do you want to change the code? What are you aiming at? The software should work as is. There is no need to change any of the code as long as you have used the same hardware as in the original design.
This sounds as if the whole button circuit needs to be thoroughly checked and maybe parts need to be rewired. When checking your circuit, assume nothing but check all of the wiring.
Scope-O-Matic uses a display with a resolution of 128x64 and a specific driver and fitting code to display the signals on it. I’m not familiar with
so I can’t tell you how to map the display output to this crt tv device. Do you have some information about it?
Furthermore, I would think a CRT display will allow for a much higher resolution than 128x64. A 128x64 image would likely look very small and blocky on it. So maybe you would want to got the analog way and transform a tv into an oscilloscope? Maybe have a look at this:
or this:
But be carefull, a TV contains some very high voltages and you could easily get hurt or worse if you are not well versed in working with that type of electronics .
There is more to it than having a few pins available I’m afraid. For showing an image on the oled in Scope-O-Matic timing is important and the same goes for the TV oscilloscope.
The challenge will be to combine those and to fit all the code in memory.
An opamp could be used to raise the input impedance of the device and the sensitivity should you wish to do so. And if you hook it up to a mixing stage, you can see the result of mixing the signals connected to that as well. Is that what you meant?
