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#1 fantasy1988 Oct 07, 2012 11:24 AM

Diy esc brushed for car
 
hello, esc brushed on http://homepages.paradise.net.nz/bhabbott/bridge.html
i use very good,but it is no brake,because i donot know write ASM for 12f675
help me diy esc brushed car with break
thanks you very much

#2 fantasy1988 Oct 07, 2012 11:34 AM

help me

#3 fantasy1988 Oct 07, 2012 08:48 PM

hi,this is board esc brushed 7,2v

#4 fantasy1988 Oct 07, 2012 09:19 PM

i am use lm2576 bec 3a,and 6 fet 3205, pic 12f675,mc34063
very good but no brake.

#5 Bruce Abbott Oct 08, 2012 06:18 AM

How do you want the brake to work?

1. Reverse throttle = Brake only.

2. First application of reverse throttle = Brake. Back to neutral and then reverse throttle again = Reverse.

3. Brake at neutral, reverse throttle = instant Reverse.

#6 fantasy1988 Oct 08, 2012 07:01 AM

thanks Bruce aboott
i want brake same esc brushed 320a car


http://img.alibaba.com/img/pb/910/89...899910_549.jpg


2. First application of reverse throttle = Brake. Back to neutral and then reverse throttle again = Reverse.

you can write code Asm or C for 12f675 or 16f688 ? thank you very much

#7 fantasy1988 Oct 08, 2012 09:40 AM

schematic esc brushed car no break
http://homepages.paradise.net.nz/bha...ge_circuit.gif

#8 Bruce Abbott Oct 08, 2012 04:05 PM

2 Attachment(s)
It's just a firmware change, the circuit is the same.

NOTE: I have only tested it on a breadboard. Everything seems to work, but I can't guarantee that it's bug free!

Here's the asm source and hex file for a 12F675.

#9 fantasy1988 Oct 08, 2012 06:08 PM

Thanks, Bruce abbott
I will use the following and report the results

#10 coro Oct 09, 2012 01:59 AM

Quote:

Originally Posted by Bruce Abbott (Post 22942830)
How do you want the brake to work?

1. Reverse throttle = Brake only.

2. First application of reverse throttle = Brake. Back to neutral and then reverse throttle again = Reverse.

3. Brake at neutral, reverse throttle = instant Reverse.

Well, I am missing option
4. advanced sensing of rotation, where instant move to reverse throttle would proportionaly brake at limited brake force, and after it really stops, then goes reverse - gently to save gears. The same for transition from reverse to forward.
Because 1. is not applicable for car/ship, 2 needs hard to find center of throttle, and 3. would strip the gears instantly.

#11 fantasy1988 Oct 09, 2012 02:21 AM

Quote:

Originally Posted by coro (Post 22951402)
Well, I am missing option
4. advanced sensing of rotation, where instant move to reverse throttle would proportionaly brake at limited brake force, and after it really stops, then goes reverse - gently to save gears. The same for transition from reverse to forward.
Because 1. is not applicable for car/ship, 2 needs hard to find center of throttle, and 3. would strip the gears instantly.

hello coro,
use the brake like esc 320A is very good, I almost completed the circuit like this esc, but I do not know the program change ASM 12F675
i will build esc for car 1/10 runs well

#12 fantasy1988 Oct 09, 2012 02:33 AM

My esc circuit has the following components

mc3406 create 20 volt activate sources fet h profile because I use a 7.2 V battery.
20 -7.2 to 12.8v the size of fet run well

LM2576 Creating 5 v 3a

opto lm 324 fet driver from chip 12f675

runs very well, but there is no compression braking is not perfect

#13 txtchain Oct 24, 2012 10:41 PM

change PWM frequency in Bruce's PIC12F675 code
 
Hi Bruce,
I made an ESC with your PIC12F675 HEX and it is woking fine. The PWM frequency is around 2.7KHz. Is it possible to change the PWM frequency to around 600Hz, 300Hz or 70 Hz, some brushed motor works well under lower PWM frequency.

Sam

#14 fantasy1988 Oct 28, 2012 06:46 AM

hi bruce abbott
after a long time of check, circuit runs fine foward,reverse and brake, but I see the program appear some errors

1 pulse limit your program 1.8ms...........1.5ms.............1.2ms

if run forward too 1.8 or run reveser than 1.2 servo control pulse, the circuit automatically cut off, and set the initial state to the joystick in neutral position 1.5 This affects the speed when I'm playing
very difficult to adjust max 1.8ms and min 1.2ms of tranmiter 27mhz for car
So, if the pulse exceeds 1.8, or 1.2, motor max speed foward ,or max speed revese.,do not cut off

2 as txtchain said, 2.7khz frequency is relatively high, change down from 100Hz to 600Hz. some brushed motor works well under lower PWM frequency.

thank you very much

#15 fantasy1988 Oct 28, 2012 09:46 PM

we are looking forward to your early reply.
thank you bruce abott


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