AlkaM's blog View Details
Archive for April, 2017
Posted by AlkaM | Apr 19, 2017 @ 07:51 PM | 20,337 Views
First off thanks to Steffen , B. Konze, SimonK and everyone who contributed to any of the open source firmwares. I can code a little but having access to well written, up to date firmware has allowed me to make these hardware abominations possible.
I know these escs in my blog aren't revolutionary, the schematics are usual modifications of reference designs datasheet schematics. I make them fast so I can use them for a project then go on to the next one. So they are crude and probably break MANY "best practice" guidelines for pcb design. They do all work and they are all tested but proceed at your own risk if you decide to make one. I hope they are of some educational use to someone out there.

This next esc was a board I was using to play around with BLHeli_S. Its uses a silabs EFM8BB21F16G (bb2) chip but the QSOP version so its really easy to solder by hand. Also the driver is the fan 7888 again. I like the combination as long as space is not a problem. They are not expensive chips. The two switching regulators I used were the same as in the last post the aoz1282 and the ap3012. (Really its the same parts with a silabs chip tossed in there! Remember to set the vreg at 3.3 though). It uses a more typical ESC layout though with the power input on one end and the motor on the other. Since it was a test board there are pin headers for the C2 connections, input signal and ground. Gerber files and diptrace originals in the zip again.

The specs are really...Continue Reading
Posted by AlkaM | Apr 11, 2017 @ 07:02 PM | 19,718 Views
I mean total failure, I plug in wires backward, had countless mosfets blow up in my face, I have vaporized wires , connectors, batteries, pcbs and drivers! I have left scorch marks on my dining room table from things gone awry. I have burnt myself, shocked myself, cut my fingers on props and pretty much failed spectacularly in every single way you can.

When you build circuits failure can be a good thing. My first circuit I built when I was young was from a kit, fm radio I believe.. I followed instructions and it worked , probably good because it got me interested but I didn't learn all that much about electronics. Many years later I decided to make a circuit off of some h-bridge or other from the internet. It seemed very simple.. how hard could it be? It blew up.. not once but multiple times before I learned what I needed to know. I'll never forget the lesson that h-bridge taught me, probably still have scars.

I still do a lot of stupid things.. check out the gallery below for some of my recent blunders.. The point is this.. don't get discouraged by mistakes no matter how much time or effort or money you think you have wasted in doing so. The things you learn from failure far outweigh the things you remember from succeeding.

Here is another speed controller anyway.. this is for more of a tinkerer. I wanted to do something with the FAN7888 as it was relatively cheap. There are a number of different options for the switching regulators and the boards I tried to...Continue Reading
Posted by AlkaM | Apr 10, 2017 @ 04:10 PM | 21,093 Views
A couple more nfet designs. I had a friend who had a hw30a esc die on him. It was a yellow covered knockoff HW/ XXD30A esc. One of the mosfets failed, upon closer inpection there were three different variation of the nikos p0603 mosfets. These were clearly not from the same batch or maybe even the same manufacturer. They still sell these things by the thousands today on ebay ! The other thing they do is use two transistors to switch the top gate, not arranged to increase switching times but it only seems to invert the signal from the atmega8. Something that can be done through software.
Anyway I got to thinking about how I can make a HW30A dpak type design with the following criteria
1) Has to be cheaper than the cheapest ebay esc.
2) Has to handle more current than the xd30a and be more reliable.
3) Must be solderable by hand.
4) Uses minimal component count and repeating values where possible.

In the end I ended up with a couple different designs, one uses all 805 sized parts but is a 4 layer board, the other is a two layer board that was made for a specific enclosure but is quite slim and very long.

The parts list went like this

regulator 1117 5.0v
10k resistors x10
33k resistors x 3
2.2k resistor x 8
100r resistor x 6
Atmega8 processor
LED 805 size
irlr7843 mosfets x 6 (3.3mOhm vs 6.5 for the nikos)
1 uf caps x 3
0.1 uf caps x 2
10 uf cap x 1
10uf tantalum x 1
3 sot-23 transistors 2222a?
470uf rubycon cap

That put...Continue Reading
Posted by AlkaM | Apr 10, 2017 @ 03:10 PM | 20,438 Views
The next few boards are variations of the charge pump, driverless all nfet design.

I really liked the simplicity of this type of esc. I was searching for a mosfet that was cheap to buy and had a good current capability but was still hand solderable. The mosfet that stuck out was the psmn2r4 . This is a 3.3 mm design that still has legs and costs about 30-50 cents to buy. The 2.4 mOhm RdsOn was pretty decent and i have not had one blow up on me yet.

There are two layouts here, one for a two layer board. I have been flying with these ones on my larger quad for over a year.
The smaller of the two is a four layer board, a little harder to do yourself but does shrink the size down to something thats in the realm of possibility for a mini quad. I am using these esc's on two of my quads ( 6 inch and 4 inch ) with up to 4s battery.

They handle damped light and blheli just fine. The firmware for blueseries n-fet 30amp will work.
The schematic is the same as the last board. There are a number of different configurations that I played around with based around that general circuit design. Different mosfets and package options. I will put all of them up here eventually.

All source files and gerbers are included in the zip.

EDIT : BIG thanks to Hiidtubakas for taking my terrible schematics and making some sense of them.. his cleaned up schematic added to the pics.