VDI-RODERICO

[roderico]

this firmware is only for testing, I renamed to v3 because it is not backwards compatible with v2 but it is v2.1+buzzer code, you would only need to disconnect your speaker and connect a buzzer to pin 13, R16 should be 1W or greater than 330R. The main issue is the bad performance of the buzzer for locating targets and it would be good if you could test it in the fields. You can select the vdi range where the buzzer will be enabled, e.g. from -45 to 90, the frequency for VDI+ and VDI- and the duty cycle. Currently it is set for a 32R speaker, if you need the buzzer to be very loud you would need to set VDI+ to the resonance frequency of the buzzer e.g. 2.4KHz and 50%.

[kroman01]

I use displays with the KS0108 controller for me, it is clear that I can change the backlight to control the speaker

[roderico]

no need to change the pic for testing, you only need to move the backlight control to the open drain (RA4) which is not used and then connect a buzzer to RC2, I have modified the last schematic to show how it would look like, what display are you using?

[kroman01]

it will be good if the microcontroller does as much as possible, i.e. it will eliminate all potentiometers and switches and make a sound,
adjustable low tone mute for negative indications, PIC24 family microcontrollers have low supply voltage up to 3V6, but this is not a problem,
I care more about the behavior of the TX generator in a system with its own resonance

[roderico]

scrungy_doolittle already suggested to use PIC24 and I think he is trying to do something similar, i.e. to move some of the detector features to the microcontroller. I'm proposing something more simple, e.g. to use the PWM module to generate a beep for positives and another beep (with different frequency) for negatives and thus replace all the audio stage if the latency problems could be solved...

[kroman01]

if not PIC18F4520 then maybe another microcontroller will be important availability and favorable price

[roderico]

it's not the microcontroller, if you want to test it I can upload the firmware but it only works with X and Y channels (not X+)

[kroman01]

maybe another microcontroller. PIC18F4520 easy availability and affordable price

[kroman01]

I was thinking of creating something similar to Fortuna M there are two analog tracks X and Y but I lack the third X+ and static AllMetal

[roderico]

I did a test some time ago with a similar idea but with a simpler circuit, i.e. half idx and the discrimination and audio with the microcontroller (with a buzzer), the problem is that to minimize the latency you would need to use the first x, y values for turning on/off the speaker and this makes the audio signal even less reliable. The only advantage is that is very small and compact but performance is much worse.

[kroman01]

hello roderico presenting my modification of IDX I wanted to leave the analog RX generator and RX U1 U2 circuits, as well as U3 U4 and U5 keys, and replace all remaining blocks with a microcontroller

[roderico]

ok thank you

[kroman01]

Your VDI works fine, although in reality it only gives distorted readings just on the edge of view. I placed another diagram with some minor corrections. These patches are due to the fact that I always make a circuit board without drawing a diagram, which I had to create especially for you
IDX_mod._kroman_3.pdf

[roderico]

are the vdi values more stable in your idx-mod with respect to the original idx?

[kroman01]

definitely better thanks to the increased amplitude, TX has large ranges and the X + channel effectively cuts false signals from wet grass and coil vibrations