in need of a really small esc

[viper2020cobra]

how difficult would it be to build a brushed esc that can power a pager style motor it dosent even have to be bi directional it can be uni directional i would need a total of 4 esc so i was thinking of just putting it all on one pcb.. is ther any diagrams or information of how to make one someone could give me?

[AndyKunz]

Castle Pixie was about 1/2" x 3/8", but you can do better. You can put a 6-pin micro (PIC 10F) and a SOT-23 or SO-8 FET together a bypass cap on the micro, a resistor to the FET gate and another for pulldown.

Andy

[Chippie]

There is Mike Norton's design which I believe was enhanced by Bruce Abbott...It is pic based(12C508?)...if you used smt versions you could make it small and compact...

Here's the link to it........

http://homepages.paradise.net.nz/bhabbott/esc.html

Bruce hope you dont mind my linking to your site....... ;)

[andrewm1973]

Vipercobra,

Do you need absolute smallness ?

A 4mm x 4mm MLF packaged CPU and 4 SC70-6 FETs would get you down to the 0.2 gram mark. I can lend you a hand with the coding if need be.

[viper2020cobra]

andrewm1973


actually i was gonna try to use some small micro componets to piece together a controller system for my micro heli project to try and get away from programing put it seems i cant escape it so ill just use one of your picoos replacment brains and save my self a whole lotta money and head aches.

[andrewm1973]

Viper,

None of the units I am making will have 4 ESC outputs. The most complex one will have 2 ESC and one H-Bridge big enough for a motor.

The programming won't be hard and I can guide you through it step by step.

[viper2020cobra]

andrewm1973

so a mlf packaged cpu and 4 sc70-06 fets will give me 4 esc that i can connect to a tiny reciever such as a pixie ? is there any chance i can get somesort of a quick drawn diagram and wich cpu do suggest an attiny 90 would do that job?

[andrewm1973]

Viper,

The CPU choise is probably pretty irrelivent. I would choose an AVR myself. The biggest part of it is the software.

If you want to hook up to a pixie then you will need to have 4 input pins (one for each channel) if you wanted to just go with IR control you only need one input pin. Going with the pixie idea means you could use an off the shelf gyro and plug it in between the RX and the ESC module.

Just to make life easier I would pick a CPU with 4 hardware PWMs. The ATTiny45 meets that bill but it has a limited number of pins left for input. It is also the same sized package as either the ATTiny44 or the ATMega48. So just to make like easy and not cost any weight the ATTiny48 would be my choice.

I am sure the PIC people will comment on the small PIC CPUs with 4 hardware PWMs. I can't point you in any direction there if you wanted to go PIC.

[viper2020cobra]

okay i like the pixie idea

and like i said i actaully need 2 uni and 2 bi channels

for teh 2 uni channels i was gonna use the sc70-6 mosfets and for teh 2 h- bridges i was gonna use the allegro a3901

and for the cpu oim gonna go with the atmega 48

what esle should i need to know?