As you know V3 meant both a hardware and a software change, the later taking most of my time so I decided that in order to please everyone I could do V2.1 a hardware upgrade of V2, and still use the same analyzing algorithms. This way all the people that waited could get their spectrum analyzer, and while continuing to provide V2.1 to all the new customers I could work in background on V3, without the pressure of deadlines that I could never keep. This way when V3 is ready I'll just post an update, so there is no need to ask when its coming out, I will continue to manufacture V2.1 until V3 will be ready to replace it.
With V2.1, I addressed the most important features reported by customers as well as some issues to help during assembly of the boards. Here is a list of changes for V2.1:
- Changed DC Power Jack from TH to SMT.
- Changed input pot from TH to SMT.
- Added new dc-dc converter ST1S10, works on higher frequency.
- Changed all pasives from 1210 to 0805 size.
- Added two bypass capacitors to ATMEGA64.
- Added reset circuit protection to prevent unwanted resets.
- Changed ISP con from simple to locking.
- Removed 100uF cap from ATmega VCC pin.
- Changed audio input con from RCA to surface mount 3.5mm jack.
- Increased clearance size for copper fill to reduce pcb failure rate.
- Redesigned LED Matrix pcb so now its 230mm long instead of 232mm.
I guess one of the biggest problems of V2 was the noise coming out of the inductor. The noise was being generated by the inductor reaching Isat together with the rather low frequency converter. The ST1S10 used on V2.1 solves this issue by working on a higher frequency thus requesting lower value inductors which have higher Isat.
The reset circuit protection was added so that no reset will occur unexpectedly, as reported by some users. With V2.1 it shouldn't matter if you touch the board or if you're running it in a noisy environment, it shouldn't reset on its own anymore.
The audio input connectors were changed from RCA to 3.5mm stereo jack because its a more standard connector so cables should be easier to find, also this makes it easier on the assembly and occupies less space on the board.
I increased the clearance size for ground copper fill on both the motherboard and the LED matrix because with V2 I encountered some failures in the LED Matrix boards because the clearance was too small, there were some boards where the ground copper fill touched a signal. This meant losses because I had to scrap those boards.
I redesigned LED Matrix pcb so now its 230mm long instead of 232mm, the distances between the mounting holes stay the same though, so if you already have an enclosure for V2, the V2.1 will fit without any other changes. I also decreased the side between the bargraph LED's so they now stick closer together.
These are all the changes worth mentioning, there were other smaller adjustments made to the parts libraries to make the assembly process easier but they are not worth mentioning here. Besides the spectrum analyzer this time I'll also be offering an addon board that will connect to the motherboard and will allow the user to run wires, and form custom, bigger LED matrix. This should make the process of building a custom display easier. The addon board will have 8-soic package MOSFET's on both the rows and columns, and while I'm only going to offer them in a couple of values (5A and 7A, not sure yet which values to choose), you could replace the mosfets with any compatible 8-soic mosfet handling a higher current. Ofcourse there will be limitation in therms of the PCB trace width, because I designed it to handle 10A safely which could be stretched if you know what you're doing but I wouldn't recommend it. Anyway If you need that kind of power(>10A) Its best to have a custom design made.
About the date these boards will be ready for ordering, it should be pretty soon. I've already sent the files for PCB manufacturing, I'm placing the orders for all the parts Monday/Tuesday so it only depends on shipping times which at this time of the year could take a bit longer than the usual (from China to Romania for the PCB's and from US to Romania for the parts).
That's it for now, I hope this news made most of the customers who were waiting happy, and for those who were really waiting for V3, don't worry I'm going to continue work.
If you have any questions feel free to post them.
Bellow you can checkout pictures of the spectrum analyzer and the other products offered in the online shop:
