This is my approach to a tiny, lightweight, powerful, and state-of-the-art 4in1 BLHeli_S ESC. As of writing this, it is probably the world’s smallest and lightest ESC that has been designed so far. I developed it during my journey of building pepperF1SH — the world’s lightest brushless FPV quadcopter.
Recently some Chinese sellers picked up my design, removed the fishpepper logo, produced and started selling my design under their name. You can see a picture of the outdated revision 0.4 they copied here. They violate the license under which I shared the design with everybody. I wanted to have the design open so everyone can learn from it. It is really a pity that they decided to remove my logo and do not mention where they got their design from and sell it as theirs. Right now I am not sure if I am going to continue publishing my future designs under an open source license… This is the reason why you can not find my tiny brand-new ESC design with 2S support on my website yet.
Even though this thing is really tiny, it features all the features you nowadays expect from a state-of-the-art ESC. It has the same dimensions as my tinyFISH FC and both can be fitted perfectly into a low profile stack.
- 16x16mm M2 hole-to-hole spacing (20x20mm outer dimension)
- a total weight of 1.2g (!)
- DSHOT600 (rev 0.5 and higher)
- regenerative breaking
- 4.3A continuous current
- openhardware + opensource software
Please note that this board is for 1S operation only. Do not even try 2S, the board will be immediately releasing all it’s magic smoke and stop working…
This board uses some hacks to squeeze all components into this small form factor. It is something the other 1S ESC vendors used in the past as well, but it is against what you learn on how to design hardware. The EFM8BB10 microcontroller used on this ESC has an absolute maximum voltage rating of 4.2Volts and is powered directly from the Lipo without any voltage regulator in between. Looks like a perfect match for an 1S Lipo, right? — Not really. This is specified as absolute maximum rating, not something the device should be operated on permanently. One might argue that the 4.2V are never applied long, the voltage begins to drop instantly when you connect your copter as a typical vtx/camera combo draws around 0.4A. You have to remember that this ESC is running the Blheli_S firmware with regenerative breaking. So in principle the Voltage of 4.2V could be exceeded when the ESC tries to stop the spinning motors. All my prototypes have survived this so far, seems like they are quite robust and/or the moving mass on the tiny 1103 brushless motors I use is just not big enough to cause big voltage spikes. And as mentioned before, other ESC vendors did this in the past as well. Still, this causes a guilty conscience, poor little EFM8 CPUs.
Please refer to post “tinyPEPPER – how to build your own” for a detailed list of components and links to the open hardware design files. This should give you all the information you need to build your own tinyPEPPER ESC. If something is missing, please let me know!
– switched to efm8bb21 (pin compatible)
– better tabs (you can now solder from the side)
– added motor phase tabs
– initial release
You might wonder why I release all that for free. The reason is simple, I just love open source stuff. Most of my knowledge is based on tinkering with open source stuff since my childhood. This is my way to give something back to the community so please respect the license and release all work you do based on my design under the same license.
Please note that you need a recent version of Kicad to open the files. I compiled my own binaries from Kicad commit hash #efdfaeb.
You will need no special programmer for this, any usb to serial converter will do. The EFM8 devices come with a bootloader and I wrote a small python script that will do the flashing. Have a look at this tutorial on how to flash BLHeli_S to the tinyPEPPER ESC.
The latest revision is currently being test flown by three friends of mine and myself. An additional pepperF1SH copter that incorporates this ESC will be soon be sent out in the context of the pepperF1SH world tour 2017.
Where to buy
I do not sell this. You can not buy it from me. So for now you will have to build your own, this page should serve you all you need.
The first clones without proper credit start to pop up. I can not recommend to buy there as they do not care about who designed the stuff. But go ahead and buy there, I would probably do the same. Just feel some seconds guilty for supporting this theft 😉
- tinyPEPPER ESC (old) rev 0.4 on Banggood: relabeled as Racerstar Star4
Here is a list of recent blog posts covering the latest status of my tinyPEPPER ESC project:
Right now there is only a collection of single posts, i will update this project page soon.
- Racerstar F3D8 VS fishpepper tinyFISH FC (3/31/2017)
- tinyPEPPER ESC – How to build your own! [v0.5] (3/23/2017)
- pepperFIISH — 2S prototype thrust testing video (3/12/2017)
- pepperFIISH — 36g copter and 288g thrust (8:1), anyone? (3/11/2017)
- tinyPEPPER ESC – How to build your own! [v0.4] (2/21/2017)
- tinyPEPPER ESC – initial BLHeli_S flashing tutorial using the efm8 bootloader (2/21/2017)
- tinyPEPPER ESC – How to build your own! [v0.3] (2/15/2017)
- tinyPEPPER ESC — SNEAK PREVIEW: PCB Layout and BOM! (2/4/2017)
- tinyPEPPER ESC — soldering party! (1/30/2017)
- betaflight — custom motor ordering made easy (1/19/2017)
- tinyPEPPER – testing with an spracing f3 evo brushed (converted to brushless) (12/17/2016)
- tinyPEPPER – first prototype soldered (12/14/2016)
- uESC – blheli_s firmware adaption & testing the electronics (10/19/2016)
Please refer to my disclaimer that applies to all projects presented on this blog.