AlkaM's blog View Details
Archive for March, 2017
Posted by AlkaM | Mar 29, 2017 @ 07:46 PM | 19,516 Views
This esc is an all nfet design similar to what you find in the blueseries escs or afro esc's or many others. How this design works is by using a simple charge pump arrangement to drive the gate of the upper nfet. Slow to turn on because the gate has to be turned on through a resistor that also limits the current while the gate is off. Fast to turn off.
Because the gate is in the off state more than on, current is flowing through that resistor most of the time and because of the thermal limits of the resistor.. This will be the limiting factor for this type of esc high side turn on time. Knowing this you can play around with the value depending on the voltage you intend to use. If you only need it to run on 2s then you can lower the value of this resistor and have a higher current to turn the gate on.
This goes for all ESC's using this type of nfet charge pump drive. R29 in this picture below.

The common value chosen is 2200Ohms by most manufacturers, this allows safe running at 16 volts. 16V / 2200 = 0.0072, i^2 * r = P = 0.11 Watts. This is even still slightly over the package 1/10 watt limit for 603 sized but under for 805 sized resistors. There is also a diode drop and the fact that its only conducting 2/3 of the time so its fine. If you only use it for 8 volts then you can lower the resistor. You cant just bypass the resistor out because then you would have a short from V to ground though the diode that charges the cap.

The low side switching time will be...Continue Reading
Posted by AlkaM | Mar 27, 2017 @ 07:43 PM | 19,609 Views
Another budget diy Board, A step up from the 8mhz multiWii. All the files and diptrace originals are included below again.

In keeping with the dirt cheap diy theme, this one uses all 805 sized parts that can be sourced cheaply from ebay. It still uses a i2c gyroscope the mpu-6050 because you can buy them anywhere. If you can't buy a bare chip you can desolder one from a breakout that costs a dollar.

There is a usb port and a ch340g usb chip on the backside. Its an enormous chip but.. hey you can buy a bag of them (literally.. they came in a baggy) for a few dollars. There is also a spot to solder a small memory chip and decoupling caps for blackbox use, I have never tried it. It should work. If anyone actually builds one let me know!

Its not fancy and nothing special, simply an F3 board and can run at 4k/4k that you can build yourself for 5-10 dollars.
Posted by AlkaM | Mar 27, 2017 @ 07:22 PM | 19,480 Views
Here's another flight controller,

I think this is just about the absolute minimum you can fly with. Its the slowest cheapest processor with the fewest number of components running at half the speed on an internal clock , a cheap mpu 6050 breakout sits on top. You can stack a bmp180 and a hcl5883 on top if you want more sensors.
I fly with this on a quad with 10 inch slowfly props and it fly's pretty well considering. There are a few of these flying about.

Here are the gerber files and the 8mhz multiwii sketch for it. I can't remember what I changed to make it run at 8mhz so I included all the files.
Costs between 2-3 dollars to make including the mpu-6050.
There is no point to this flight controller..
Posted by AlkaM | Mar 23, 2017 @ 11:59 AM | 19,641 Views
I wanted to make a flight controller without all the bells and whistles so I could make a bunch of cheapo quads.

I realize that I really don't care about most things flight controllers are offering. I just want something that can thrown together with few parts put into a quad and fly.
There are two versions a 36x36mm board with an integrated PDB and a 27x27 ultra basic board. There is a header on the 27x27 board that takes those cheap ebay modules ( 5883 mag, bmp 180/280 ) if you want to add a sensor or two.
The cost to build these is about the 5-10 dollar mark. They are all a two layer board with 805 sized parts so soldering by hand it easy.

Here are a couple of the boards I am using, I use an ftdi adapter to program them and talk to the fc software. I have a version with a built in usb port but in reality I just don't need to fly around with it all the time. They are the same pinout as a SPracing f3 board. Please don't think that this is a "clone" I simple needed to use a pinout so you don't need to build a custom firmware. His board, I am sure is much better than this.

I will attach gerber files and schematics, also the diptrace files are included in case someone wants to customize or build their own.
BOM to follow if anyone is actually going to build one.

I will try and keep adding home built electronics to this blog. To me, building your own is the only way to go, that is the hobby for me.