Digital VuMeter to done with Arduino R4, 3.5 TFT touch screen.
I would like to receive feedback on my needle digital vumeter project, made with an Arduino R4 and a 3.5-inch touch TFT screen. The structured input is very simple, the logarithmic function is executed by the program, and you can personalize the color and theme to your liking.
This is a carattezization about the logaritmic fuction
Best Ragards,
Sebastiano.
I would like to receive feedback on my needle digital vumeter project, made with an Arduino R4 and a 3.5-inch touch TFT screen. The structured input is very simple, the logarithmic function is executed by the program, and you can personalize the color and theme to your liking.
This is a carattezization about the logaritmic fuction
Best Ragards,
Sebastiano.
Cool looking display. I think maybe a problem at low levels though. Even a schottky has a Vf, and I think this one will be around 300mV. Conversely the reverse voltage on BAT54 is 30V, so a high power amp will exceed the limit. Nothing horrible will happen, but the value displayed will be wrong. There are many active diode circuits around. I tend to use the one from the 70's from National's linear app book for stuff like this. Back in college I built a discrete version of what you are doing with a row of 20 LED's for each channel with the National circuit doing the AC/DC conversion followed by LM339's triggering at different thresholds driving an LED.
I used a voltage divider to set 2.5V on the Analog pin, then AC couple the signal. Gives more options that way and eliminates the diode forward voltage problem.
Maybe add zener diodes to protect the Arduino from over voltage too.
Is there any driver level optimizations attempted to speed up the screen response?
Maybe add zener diodes to protect the Arduino from over voltage too.
Is there any driver level optimizations attempted to speed up the screen response?
Yes, way easier to do the rectification in the arduino if the ADC is fast enough. 50KSps is probably plenty. I've used one of those TFT's that adafruit sells and used a pico-w to drive it with spi/X. Kind of slow for initial draw, but updates were decently fast. I expect X is bit banging only the pixels needed while the initial setup required all pixels to get set. I think most of those displays are spi which I think can hit 10mb/sec transfer rates.
Nice Work!
Do you want to share with us?😉
If yes,post all files, schematic diagram and xxx.ino 😊