This module is MFOS Echofxxx.
Original schematic and BOM: MFOS
-D1 & D2 = 1N5231
-D3 & D4 = 1N914 or 1N4148
-100nF, Decoupling capacitors are soldered underneath the boards, so I omitted them in the layout
The dimension is 40mm x 129mm.
The layout is actual size so you can use is as a drilling template
-Pot hole: 7mm
-3.5mm jack hole: 6mm
-Screw hole: 3mm
Original schematic: MODWIGGLER
The original circuit was good enough to use, however I wanted comfortably aligned 10Vpp outputs. So I added a simple opamp circuit to get the outputs 10Vpp and aligned from 0v. You probably wonder why I used fixed resistors instead of trimmers to control output voltage. Because I decided to add the opamp circuit after having finished 555 timer circuit, so there were not much room. I would have used trimmers over the resistors to get more precise result if I build it from scratch.
It's a usb lamp using 555 timer.
The color codes might be different from above. In the case, you would use a multimeter to discern +5v and ground wires.
Schematic and more information: Kassutronics
This module is an attenuator and an inverter at the same time and also a mixer with an additional input.
It works as an attenuator when the potentiometer is from center to right (fully clockwise) and when you rotate the potentiometer counter clockwise from center, it starts inverting the signal.
I used +5v from PSU, so the offset function might be unstable.
If your PSU doesn't have +5v or you are worried about it, you would build it with LM4040. In the near future, I'd also build another one with LM4040 and compare both and see the difference.
And the potentiometers I used are center-detented, which is so convenient to know where 0v is.
As always I soldered 100nF decoupling capacitors underneath the boards so you can't see them on the stripboard layout. So please don't forget soldering decoupling capacitors when you build this module.
The dimension is 40mm x 129mm.
This layout is actual size so you can use it as a drilling template.
Original schematic and more information: LINK1, LINK2
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