Triple Function Generator project

my only question would be,
how do you people clean the pcbs?
I use 99% isopropanol and a toothbrush, but at the end it always ends up with a sticky residue.

The same as you. sometimes I use a toothpick or flat screwdriver to remove flux blobs.

Some earlier discussion on PCB cleaning:

1 Like

I do nothing cleaning-wise, and i’ve never had any problems.
YMMW wrt. flux use, of course.

Two pictures from the TFG:

7 Likes

My PCB kit arrived last week, still trying to track down a couple of components though.

With the 4.2k resistor, 4.32k is listed as an alternative; I have 4.3k resistors on hand, would they work as well?

jup!

4.2k is hard to find, so anything that comes close is usable

1 Like

Question on switch wiring - can someone indicate which numbers on the DPDT pinout diagram on
http://www.learningaboutelectronics.com/Articles/Toggle-switch-wiring.php
correspond with A B C D on the pcb? Thanks!

the dpdt switch has 2 rows of 3 pins.
1 2 3
4 5 6

connect A & B to row 1 (2 & 3)
connect B & C to row 2 (5 & 6)

the switch makes or breaks a single connection between A & B and C & D
So two of the pins are not used, they are ‘open connections’

1 Like

Just finished one channel of my build. My video setup is still a work in progress but this makes a fun waveshaper/folder(?)/rectifier for audio, especially when gradually adjusting audio input level before going into the TFG :star_struck:

3 Likes

The buildguide is almost done, sorry for the delay!

and here it is: (as PDF downloadable)
https://www.reverselandfill.org/diy/triple-function-generator-project/

direct link:

6 Likes

Hi Martijn,
Could you comment on the intended function of the toggle switch?
By my reckoning it looks like when in the A-B position it increases the bias of the first op-amp’s negative input (i.e. moves the virtual ground slightly higher) and when in the C-D position it adds in a little bit of negative bias to the input of the summing last op-amp.
So I think the two switch positions shift the output voltage level, and change the position of the three adjustable bands slightly, which is essentially confirmed by what I see on my scope. Is that right or have I missed something?

EDIT: Never mind, I’ve worked out that it’s a bipolar/unipolar selector, switching the midpoint between 0V and 0.5V. It all made sense when I scoped it with a +/-1V ramp wave input rather than a +/-12V sine :slight_smile:

the switch sets the range of the lights-mid or mid-darks
just plug in a video camera source and you will get it :slight_smile: -> by adjusting the pots I mean

fixed the buildguide, thanks @GijsvO
the R4 / 100r resistor was not in the guide, now it is :relaxed:

1 Like

Are there any videos of this module in action yet?

Just open this up in three tabs: https://www.youtube.com/watch?v=ensZd7VvbTw
:grin:

In all seriousness though, the Sandin IP Function Generator module in that clip is what the Triple Function Generator is based on. The Triple Func Gen just has 3 of them in one module. I can’t remember if there’s any normalling or not. Still, I’d definitely like to see someone using a Triple Func Gen on R, G, and B channels, so hopefully someone posts something!

Yeah, that’s kinda what I was getting at, using all three in parallel or series for colorization or feedback. Need to see that :slight_smile:

I’ll try to make a video of this tonight
uploading to video right now. but internet is slow here …

1 Like

here it is:

patch info:
Camera -> sync generator -> video input -> TFG -> RGB encoder

I play with the brighness and contrast levels in the beginning of this movie, this has a lot of effect on the color shades and ranges.

For the rest I play with all the knob settings and switches to explore the different color values and inversions.

note: the scrolling color if the result of my crappy CCD camera, not the module.

5 Likes