Controlling A robot using Cheap Rc car controller. (SFDP) - Electronic Circuits Projects Diagrams Free

Mr_Max · 16th March 2006, 09:01 AM

HI every one

I Want to use A cheap rc car (transmitter & reciver) to control A Small robot

the problem is due to high power source i want to use(gp 7.2v 1600 mA battery)

which the two H-bridge circuits , the reciver chip shown in the circuit below aren't able to

handle that much current

so how to make the reciver circuit only control more powerfull h-bridge ( a tip's 102 & 107 or

mosfet transistors) provided that each circuit uses it own source of power

reciver circuit operating at 9v (6 aa batteries) 600 ma & a tip's or mosfet H-bridge operating at

7.2v 1600 ma

the reason that i want seperate sourcres of power is that im afraid that the reciver chip

aren't able to handle that much current (it mighty get fried)

should i use the ouput of the rc reciver h-bridge to control the tip's/mosefet h-bridge

if this is possible how ? i'm using a Mabuchi motor for throttle

included the reciver circuit,

Mr_Max · 18th March 2006, 12:16 PM

here is the h-bridge circuit i want to merge with the radio control reciver

http://www.mcmanis.com/chuck/robotic...t-circuit.html

please tell me which wires to connect & components that needs

replacement.

**Nigel Goodwin** · 18th March 2006, 12:37 PM

Quote:

Originally Posted by Mr_Max

here is the h-bridge circuit i want to merge with the radio control reciver

http://www.mcmanis.com/chuck/robotic...t-circuit.html

please tell me which wires to connect & components that needs

replacement.

It looks difficult to do?, the H-bridge circuit at the link above is quite unusual, it requires manipulation of three pins to control it. You would need to design a logic system to convert between the two systems, or find a more 'normal' H-bridge design.

bloody-orc · 18th March 2006, 03:07 PM

just connect the Enable pin to vcc (or GND whatever it need) and dont turn any attention to it. then connect the H-Bridge and the way you go

but i cant understand why cant you just change the transistors in the original schematic.

Mr_Max · 19th March 2006, 09:53 AM

Thanks alot for your interest in my topic

yes the BJT circuit is confusing ! but this is what i found.

Any H-bridge circuit that can handle the 1600ma current & the mabuchi
motor would be fine .

what is your opinion :- [NEC] 2sd401a & 2sb546 Based h-bridge

here is the datasheet

& the circuit

if any one knows a beter h-bridge that works please let me know.

& please i wish to know if the idea of 2 seperate sources of power would work or not? 7.2v to external h-bridge & 9v to receiver circuit

this circuit is my trial i don't know if it works if any one cant tell me if it does?

the idea is that by connecting the output of the reciever h-bridge (2 wires red & black)

to (a) & (b) so when i press for ex. the (throttle) forward button say point (A) would be +9v

& Point (B) would be -9v so the diodes allow the +9v & block the -9v & vice versa

thus simulating the 0 1 1 0

as i said it is only a trial i don't have much experience about Electronics

Mr_Max · 19th March 2006, 10:20 PM

I can't just change the transistors in the original schematic

because i'm afraid that the 1600ma current might fry the reciver chip

if a short happens in the circuit ?

but if you see it possilble let me know that would be great

what do you think about the NEC Transistors that are able to hanldle a 3A

current I have bought them already but i didn't solder it yet!

could these transistors be used to make H-bridge of any form

Mr_Max · 20th March 2006, 09:27 PM

I'm sorry for that mistake in the NEC H-bridge circuit the upper & lower transistors were reversed ,i hope that this one is correct

please tell me if there is any thing wrong with this circuit & how to overcome it?

to clarify :

I want your help to find the simplest h-bridge design that would do the job . no (PWM) no
(differential Steering)

I'm using this R/c transmitter & reciever circuits to control a small robot i made.

For throttle i'm using A (Mabuchi Motor) & for steering i'm using a small (powerfull) old

recorder DC motor both motors are geared.

it's a 2WD robot (2 wheels at the back 11cm radius) connected to a gearbox thorough (4 Rods & 8 joints)

& for steering (2 free wheels 11cm radius) connected together by (2 Rods 4 joints) & to the steering motor (a real car steering type)

the reason i built this robot is to simulate a real car or truck mechanism .

as shown in the provided picture there 4 shocks & the movement is transferd to the back wheels

through 2 axles so if there are small rocks in the way these shocks works great providing

A travel Radius up to 6cm (rear shocks) 4cm (front shocks)

note: the old h-bridge transistors data sheets S8550,s8050 & s9014 are included
i hope this could help!

i'm sorry but i have so many things in mind with regard to this topic ,is it possible to

use the s8550 & s8050 to drive the (NEC) D401 & B546 H-bridge

Mr_Max · 20th March 2006, 09:36 PM

s8550

s8050

s9014

Mr_Max · 20th March 2006, 09:39 PM

S8550

Mr_Max · 21st March 2006, 07:56 AM

To all Experts Where have you gone? :!:

The topic is sinking

Mr_Max · 21st March 2006, 09:08 AM

Could this circuit work for me?

included The original & the modifried circuits.

what about I/O pins cannot be floating & how to overcome it?

Help you to help me

http://www.blogcadre.com/blog/jason_...11_10_23_18_10

http://www.blogcadre.com/files/rccar-h-bridge.jpg

Mr_Max · 23rd March 2006, 08:00 AM

I will just keep replying to my self :!: :?: :?

bloody-orc · 23rd March 2006, 08:10 AM

the chip suply voltage is 5V max. you cant connect it to 7.2V ever! put a low dropout regulator betwean. for the transistors use the ones stated in the RX.-2B data on use relays driven by transistors given in the datasheet. relays can take biger currents than transistors. how to connect a relay to the transistor i hear you say? use the internet. it is full of all kinds of examples and theory articles. learn the simple principles of electonics. it aint that hard you know.

Mr_Max · 23rd March 2006, 08:41 AM

Just to confirm if i just replaced the old transistors with the D882 , b772 & put a Low Dropout Linear Regulator

i could attach the 7.2 gp battery & have no fears of melting the transistors or the rx-2b chip? :idea:

one more thing in the chip datasheet page 10 the supply voltage colud be 9v or 12v but there is a resistor that have to be changed

9v 220ohm
12v 330ohm

would this FAN1086 Low Dropout Linear Regulator be fine?

1st April 2006, 06:21 PM

Hi
Your original circuit should work fine. The tip107/102 darlingtons are rated for 8 amps, so as long as your motor doesnt draw more than that (and I doubt that it does), you should be fine. You dont have to worry about "frying" your chip because the motor current doesnt go through it. The chip just sends a low current control signal to the darlingtons - THEY handle all the motor current. Your 1600ma battery may be the only limiting factor in this setup.
PS - Thats a cool little car!

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18th March 2006, 12:16 PM	(permalink)
Mr_Max	Any one Kind enough to help here is the h-bridge circuit i want to merge with the radio control reciver http://www.mcmanis.com/chuck/robotic...t-circuit.html please tell me which wires to connect & components that needs replacement.

18th March 2006, 03:07 PM	(permalink)
bloody-orc	just connect the Enable pin to vcc (or GND whatever it need) and dont turn any attention to it. then connect the H-Bridge and the way you go but i cant understand why cant you just change the transistors in the original schematic. __________________ Need Help? Press F1 If that doesn\'t help you, ask me... I might know better.

19th March 2006, 10:20 PM	(permalink)
Mr_Max	I can't just change the transistors in the original schematic because i'm afraid that the 1600ma current might fry the reciver chip if a short happens in the circuit ? but if you see it possilble let me know that would be great what do you think about the NEC Transistors that are able to hanldle a 3A current I have bought them already but i didn't solder it yet! could these transistors be used to make H-bridge of any form

21st March 2006, 07:56 AM	(permalink)
Mr_Max	To all Experts Where have you gone? :!: The topic is sinking

23rd March 2006, 08:10 AM	(permalink)
bloody-orc	the chip suply voltage is 5V max. you cant connect it to 7.2V ever! put a low dropout regulator betwean. for the transistors use the ones stated in the RX.-2B data on use relays driven by transistors given in the datasheet. relays can take biger currents than transistors. how to connect a relay to the transistor i hear you say? use the internet. it is full of all kinds of examples and theory articles. learn the simple principles of electonics. it aint that hard you know. __________________ Need Help? Press F1 If that doesn\'t help you, ask me... I might know better.

1st April 2006, 06:21 PM	(permalink)
hyedenny	Hi Your original circuit should work fine. The tip107/102 darlingtons are rated for 8 amps, so as long as your motor doesnt draw more than that (and I doubt that it does), you should be fine. You dont have to worry about "frying" your chip because the motor current doesnt go through it. The chip just sends a low current control signal to the darlingtons - THEY handle all the motor current. Your 1600ma battery may be the only limiting factor in this setup. PS - Thats a cool little car!