I noticed Canobi's PCB has 10kohm resistors on the MOSFET section. My primary mosfet works,.. the one that uses digitalWrite,. and it also uses a common ground with everything else and NO resistor. is that what i am missing? a common ground for the PWM mosfet? i am hesitant to mix the 5v arduino ground and the 3.4v power from the Buck Step down driver.
The 10k resistors pull the pins to ground when not in use as I've been told they can sometimes float causing miss readings.
I think a good design target is to not make the board any wider than 1". That way it'll fit inside PVC that is commonly used to make lightsabers. The 1" PVC electrical conduit is also commonly used to make sleds and chassis for lightsabers, so fitting inside those would be a boon. 1" will easily fit inside MHS parts which typically have in ID of 1.25".
Cool setup. You're quite handy! I can drill and tap holes and cut things with a rotary tool. That's about the extent of my metal-working skills. (I told you I hate fabricating!)
This looks pretty good. If you are still including the LP2992 LDO as an SMD component? If so, I'd suggest just routing power from that to the VCC on the arduino for the 3.3V version if you can. The drop out voltage on that part is going to be better than anything you'll get from the on-board regulator on the Arduino, especially some of the clones. In fact, I've had some bad experiences with Arduino Pro Mini 3.3V clones using sub-spec onboard regulators that cut out at 5 volts! That won't fly when you're running a 3.7V battery.
I have taken a hard look at the drawing you posted. I have a few comments and suggestions. Do with them what you will. There is really only one error that I noticed, the rest are just ideas for improvement.1) The mappings for the Busy and VCC (3.3V) pins on the WT588D are each off by one pin. The Busy pin is right next to the VDD pin and the VCC pin is right after that. (VDD, BUSY, VCC, with no skipped pins).
2) You may not need to leave room for the clash sensor. They work best when placed as close to the blade as possible, but people often mount their soundboards close to the pommel. This means that folks will likely run wires from the board up the hilt toward the blade anyway for their clash sensor. It's OK to leave it as is, I'm just pointing out that the space may not be used often. It's an opportunity to make the board smaller, maybe.
3) If you still plan to include the LP2992 LDO, just run power from that to the VCC pin on the arduino (at least for the 3.3V version) and the VCC pin of the WT588D as well. It makes the entire part a 3.3V device with the option to add an LDO or buck to boost power to the VDD on the WT588D for more performance if desired. Otherwise, just bridge the WT588D's VDD to 3.3v as well and call it a day.
4) Why not route pins 2, 3, 5, 6, and 9 toward the inside of the board and take pins 7 (Activation Switch) and 8 (Aux Switch) out to the edge of the board? That way nobody has to solder wires for their switches to the middle of the board. I can see that becoming a big pain, especially if there is a PRO-Mini sitting on the other side and you can't thread the wire through to solder it in through-hole fashion after the MCU is mounted. The signals from the other pins never leave the board, so they don't need that premium edge real estate.
That's all for my notes. Don't take that laundry list to mean I'm not impressed; I really am. I'm excited and look forward to working out a way to combine your board with my software.
As Canobi said, he added pull-down resistors for the MOSFET gates to stop them from floating. This is sort of a standard thing to do. The reason your application works without them is that when you do a digitalWrite(LOW) in code, the Arduino will pull the pin to ground so it's not left floating. So in practice you don't technically need them. I've done it both ways.
I put the 10k gate resistors on as a precaution but if they're not essential then I'll ditch those as well it'll help to simplify hand soldering.
Well the resistors are less than pennies each but having tried it, it was a pain to solder them so close to the fet so it would make populating the board quicker and simpler to leave them off.
As to what I use, I design my layouts on my android phone. I found a couple of apps called DriodPCB and PCB design companion, both of which are totally free, totally awesome and have very little to no adds.Design companion has a ruck of useful calculators needed for working out trace widths and the like while DriodPCB is where all the fun happens as you literally "draw" the circuit using a variety of tools (some of which can't actually be used yet but the devs are working on those).
Found it!!"Now I needed to power each LED (Red, Green, and Blue) individually. This is what I came up with: Three MOSFETs wired like so: Gate goes to Arduino Nano output. Source goes to ground. Drain goes to LED negative with current limiting resistor for each LED. "Jake's been holdin out on us!!! Lol only kidding, found that post on CSS forums where they said take Arduino elswhere!! The Pertinax MkII is all I need!!! I took the dive and ordered all the parts, guess I still have to figure out the resistors and buy them too. I understand the smaller brown resistors limiting the voltage for the RGB led's, but what are the grey resistors doing? Sorry my newbness drags your guys brilliance down.
they are not needed on my 3.7v set up. have you got a working set up? have you tried with and with out resistors?
Yes, I tried both ways. It works without the resistors.