SMC3 MM Triple half bridge driver pcb

Hi guys
About a year ago I decided to build a pcb to go with the great smc3 code that @RufusDufus coded as well as the half bridge work that @Pit did to give more power ( greatest respect to both of you guys).
Now I recently found out that sparkfun are no longer stocking the genuine motor monster but I'm sure that they will still be available as the cheap clones that most of us buy anyway (at our own risk I might add) so this project might be an option for anyone who feels they have the ability to take it on.
Firstly this is not an easy project to build at home if you have little experience in pcb making due to it being double sided, uses 16mil traces, has some 0.5mm pitch soldering, 0.4mm drilling as well as making sure you have 3 PROPERLY TESTED AND WORKING motor monsters and being able to flash bootloaders onto a smd atmega 328.
So why not just use an Arduino uno you say. Well the Arduino boards are great but are designed for an infinite amount of different projects and not designed solely to do one. Just the noise on the ADC of an uno board is enough to make your eyes blead and we are using 3 of them all connected to the same ground, added to that you cant stack 3 MM's with heatsinks and fans on an uno so this means jumper wires which act as little antennas as well to make the situation worse. I measured it on my scope when setup this way and found loads of digital noise spikes on the analogue lines that got slightly worse when the fans were on full and crazy when the motors moved. I use high quality shielded cable on the pots, tried twisting wires together, moved power cables away from signal cables, used ferrite beads and even tried to put all electronics in a faraday cage which added together helped a little but not enough for my liking.
The solution for me was to build a pcb for many reasons some of which ill explain here.
Firstly the big mess of cables that there is to deal with ( I really didn't like the wires everywhere for safety reasons, it blocks the flow of air for cooling and picks up emi ).
Secondly the Arduino uno doesn't have a split ground plane between analogue and digital circuits to stop digital noise getting on the analogue plane ( digital noise leads to unwanted sim vibrations, extra heating in the drivers and excessive pwm activity). I've added this and star grounded it as well as building in some decoupling for each of the pots. Not having all the jumper wires everywhere helps some more as well as upgrading to good quality pwm fans. Keeping all the high current motor wires as short as possible inside the housing helped some more and finally we achieve a clean analogue signal from the pots with very little noise.
The pcb has the same resettable fuse as the uno has for safety as well as good noise suppression on the usb input.
So cooling then. Not being happy with just adding fans that are fairly small and noisy if you have 3 of them running as well as wanting to use 80mm pc pwm fans. This caused a few problems due to them needing to be driven at 25khz pwm and that involves messing with the timers on the atmega 328. Now rufus has already adjusted the timers on the SMC3 so don't want to mess with them so I added another atmega 328 to the pcb to drive the fans and isolated it from the Smc3 circuitry. I can now use as many pc pwm fans as I wish and good quality ones are nearly silent. It's got 3 temperature sensors that read the temps from all 3 motor driver heat sinks and drive the fans at the speed of which ever is the hottest. Also ive broken out the i2c lines and connected it to my button box with a cat5e cable. The 16x2 display on the button box shows fan rpm, fan percent and temp of each driver as well as it having a rgb backlight which changes from green to red depending on the temp.
I also decided that I wanted the housing to look better as the standard side panels were not high enough for 80mm fans. I decided to make a 3mm carbon fibre sheet, Designed what I wanted on fusion 360 then milled it out on my cnc router. Costly and time consuming I know but I like real carbon fibre and it looks great.
I have all the pcb files as well as all working code if anyone is interested in making this or if a group of people want it then I would advise getting a board manufacturer to make a few of them. Again I made this for myself to use myself and have tested it myself for the last year with no problems so feel that as ive learned so much from this site that I should give you guys something back.
Ill put all files needed on here if there are enough people that want to try to build it but you do so at your own risk.
Hear are some pics ​

Hi @yellofella fantastic work so far, never thought someone will ever do such a project. Since Sabertooths replaced the MMs more and more and it seems that the MMs are coming to EOL it's a bit late but nevertheless very useful if anyone is still interested in MMs. On this occasion I have to mention that my MMs (from 2013) are still working after thousands of hours without any issues. If you get a couple of them in good condition take it and be happy.

Hi @Pit
Glad you like it. As I mentioned ive had this for a while now but been fairly cautious about putting it on here due to how many bad MM clones there are for sale. I read on the sparkfun website that they are discontinued which is probably why you say they are coming to there end of life. Not sure I fully agree but you may well be right. However seeing that most of the people that are using them didn't buy them direct from sparkfun and purchased a clone from somewhere else at a fraction of the cost( myself included) there may still be hope. This is probably why they have been discontinued by sparkfun. I think the real problem with the MM's is the amount of bad clones there are for sale and not knowing where to get good ones puts people off, I mean if your going to pay £60 for one from the robot shop to make sure you get a working one and use it as a half bridge then for the money it is per motor you would be better off with the sabertooth or other driver. However if you manage to find some good clones then there surly not an end of life product. I bought 3 from flux warehouse on amazon and all 3 tested good and have had no problems at all and they were £9 each. Maybe I was lucky getting good ones for this project but I can say that to my knowledge I don't see anyone buying 3 motor drivers with this much power for under £30. Maybe if there was a page on here with a list of good suppliers that people had bought from it may help. Anyway thanks for the kind words buddy.