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This thread is privately moderated by AlkaM, who may elect to delete unwanted replies.
Apr 19, 2017, 07:51 PM
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Some giant Silabs Blheli_S DIY ESC.


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 dependant on how its built. Made for the PSMN series of mosfets from nxp but the footprint will work for other powe-s08 type FETS. You can find mosfets down to 0.7mOhms that will work for it.
In the board I am using mosfets with about a 3mOhm RdsOn and printed on a 2 ounce board it happily hums away at 30 amps without getting hot. I have this one coupled with a hobbyking donkey st3508 and a 12 inch prop.

I used firmware F. The dead time is going to depend on mosfet and gate resistor choices. The fan 7888 has an internal deadtime of 270nS so you can go down to F_H_0 with the right choices.
For a plane or somethings this might work quite nicely. The aoz1282 has an input range up to 35 volts the input caps and mosfets can be selected to handle that. So a budget - up to 6-7s diy esc is possible. I don't know how much current it can handle. I have only made one and I don't want to blow it up yet. I use mine for with a 4s battery and up to 30 Amps so that's all I can vouch for. Had an apartment fire before winter, lost everything.. years or prototypes, tools and rc gear so my equipment is limited. The demolition company pulled my oscilloscope from the rubble and it wasn't in bad shape considering a building fell on it, it worked! that was enough to convince me to start again ( and document things ! )

P.S Steffen, please make blheli_32 open!
Last edited by AlkaM; Mar 12, 2018 at 11:31 AM.
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May 25, 2017, 11:09 PM
eagleanurag

Which Software


hello,
your all esc design are cool. I want to ask you that wich software you used here to design your pcb .so that i may import the gerber files more accurately in it with no error.
i have cadsoft eagle software it generate gerber but it doesn"t support the gerber file which one you provide in your blog.....
so if you love to share the name of software please let us know
thanks
-Anurag Pandey:

May 30, 2017, 08:08 AM
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Thread OP
Quote:
Originally Posted by eagleanurag
hello,
your all esc design are cool. I want to ask you that wich software you used here to design your pcb .so that i may import the gerber files more accurately in it with no error.
i have cadsoft eagle software it generate gerber but it doesn"t support the gerber file which one you provide in your blog.....
so if you love to share the name of software please let us know
thanks
-Anurag Pandey:

I use diptrace for the schematic and layout file and the gerbers were exported in rs-274x format. Should be able to open those in a gerber viewer like gerbv . The free version of diptrace will work for opening and editing all the files.
Mar 04, 2018, 04:32 PM
Registered User
hehehe, I just saw this. Almost same project!!!

Have you had to make any changes to the firmware to use the QSOP?
Do you think it will work for 12S or more?
Has you seen blheli_s have temperature protection, Do you know how you connect this temp sensor?

I am also thinking about add a shunt and try to implement current limiting.
The code has the PWM limiting of temperature protection.
It would be easy to modify it to implement a current limiting
Mar 04, 2018, 10:24 PM
Registered User
Thread OP
I didn't have to change anything for the qsop. It's a pretty easy chip to hand solder too.
I really don't know what max voltage this board can take. With the component I chose here I can only really safely go to 5-6s but I'd you swap the regulator, input caps and mosfets to ones that can handle 75 volts or so it MAY work. The board should be able to handle it. Who knows, though but testing and explosions are part of the fun.


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