what PIC should i use

[seesy1234]

i confuse which one PIC should i use in my project.i want build a remote control car where it will repeat the command that i send to it without any controlling(let it move to 1 round.when i press a switch ,it will follow back the previous track that i control without control by user)..Each time i using the remote control to control it then move in any direction where controlled by user and at the same time it will automatic save the data in RAM.during playback step(without any controlling),it will read out the command or instruction that have save previous in RAM..so what type of PIC i need..and do you have any website write a program to read out the command from RAM..thanks

 

[Gayan Soyza]

Any PIC will have enough I/O pins will suits you.

Hardest part is writing the protocol.What method do you planned to transfer the data?IR/RF etc....

 

[seesy1234]

problem is the memory space of some PIC is not enough to store the command..using RF

 

[Gayan Soyza]

You are going to record the cars direction.So when it starts from a new round it will follow the previous rounds positions.

Situation like this I'll use a timer & save the time in between two positions to free GP registers along with the direction.

More positions you get smoother turns.

Looks like simple but needs to work out harder.

 

[bananasiong]

Hi,
Just choose the PIC that have enough IO pins for your applications. No worries for the memory, you can hardly use them all. With only 1 page of program memory, you can write pretty well program. Besides, if you're running out of the RAM, the program memory (flash memory) is sufficient enough for you to store the data.
What programming language are you using? There're a lot of examples of different programming language on the web.

 

[seesy1234]

ya..i want record the car direction..what you mean by use a timer & save the time in between two positions to free GP registers along with the direction?

 

[bananasiong]

ya..i want record the car direction..what you mean by use a timer & save the time in between two positions to free GP registers along with the direction?

Hi,
Timer is the internal module in the PIC that will count automatically once enabled with selectable rate. GPR is the general purpuse register which is also called the RAM.

 

[seesy1234]

if i choose the PIC16F84A,isit enough memory to store the command as recorder car direction .i'll use the assembly language using MPLAB

 

[seesy1234]

how i using the timer to record the path..i think it's impossible using timer to record the direction because the car don't know what direction we control it but it would know how long the distance to move..(e.g if we control the car move forward 5m then turn left 1m and follow again 3m,so the car wouldn't know what the direction we control but it will know how far the car move,so if using the timer i think it would move the total distance we control it only)

 

[Boomslang]

I think what he means is, move 1 second forward, then left for 2 seconds etc, save the seconds counter at every turn to reproduce the turns (more or less). I you want direction relative to north, use a GPS or electronic compass or or at least a gyro to work out the angles.

 

[bananasiong]

Hi,
Gain some experience on PIC before doing anything, like blinking the LED.
Anything other than PIC16F84A. It doesn't have much built in peripherals, less program memory as well as RAM. NO.
How are you going to determine the travelled distance?
Again, what programming language are you going to use?

 

[Boomslang]

I would reccommend a 18F part, less bank changes and stuff to worry about. An 18F2520 should be good enough for the job, and have some spare pins.

Are you planning on controlling RC servos and electronic speed controls, or is your RC car just on/off switches? As far a I know you can't use hardware PWM to control them (at least not use them if you are running the PIC at higher OSC speeds), so you have to do the PWM in software.

 

[seesy1234]

here is what i find the remote control car assembly code from my senior.just a simple to control the remote car.

 

[seesy1234]

i using 4 channel to control it(forward,reverse,left,right)..actually i don't know how to determine the travelled distance..any suggestion?what's mean hardward PWM to control them?i don't have much experince in electronic and programing..

 

[Boomslang]

If you don't have much experience, I (and I think everyone here) can reccomend you try Nigel Goodwin's tutorials first to learn the basics : WinPicProg Page

 

[3v0]

I owe seesy an apology!

This is a continuation of this thread. Seesy should not be faulted for starting a new thread. To be honest I owe him an apology!

I asked seesy for schematics but that was bad because he had previously posted a link to the RX TX datasheets and I missed it. He is using this TR RX remote control chipset . Page 9 shows the application circuit he is looking at. That datasheet answers a lot of the questions that seesy was unable to answer. Still he needs to understand the datasheet.

To make it work the uC will have to be placed between the RX chip and the 2 motors. Both steering and motor use h-bridges. It looks like there is no proportional control. So one could record a set of logic bits between the RX and motors along with how long they existed. Record and pass on in the normal mode and playback when requested.

What is lacking is some way to trigger the record playback. Maybe the turbo mode could be repurposed for that.

EDIT: This project is too advanced for his current understand of the subject. He needs to start with blink

 

[seesy1234]

3v0,u not owe me apology..actually i'm stupid because i can't anwser they question(i don't what they asking me cause i don't heard and learn before what they talk to me.)..i post this for help in this forum because i not just only need to do final year project and at the same time i also have to study(exam)..so i don't have much time to learn new thing,but i willing to learn.. the RX/Tx are the chips where they can't be program..isit i can connect them with PIC?so the PIC is useless for controlling the speed and direction isit,but useful to record the command?

 

[blueroomelectronics]

The 16F84 is rather limited, try an 18F2525 as it has dual PWM & USART

 

[3v0]

I would not say you are stupid. There is a big difference between stupid and not knowing.

Lets call the remote control chips the TX and RX. The TX connects to control switches. The RX connects to the 2 motors. What I am suggesting is that you place the PIC between the RX and the motors. The PIC will listen to the RX and pass what it hears/sees on to the motors. If it is not recording or playing back it is as if it the PIC was not there. It acts like a wire.

To record the PIC will also compress (more on that in another post) and record what it gets from the RX and still passes it on.

To playback the PIC reads the old commands from its memory and sends them on to the motors.

Does that make sense.

Do you have the RX and TX chps. If not get them ordered and working as in the appnote. Once you have that we can insert the PIC between the RX and the motors.

3v0,u not owe me apology..actually i'm stupid because i can't anwser they question(i don't what they asking me cause i don't heard and learn before what they talk to me.)..i post this for help in this forum because i not just only need to do final year project and at the same time i also have to study(exam)..so i don't have much time to learn new thing,but i willing to learn.. the RX/Tx are the chips where they can't be program..isit i can connect them with PIC?so the PIC is useless for controlling the speed and direction isit,but useful to record the command?

 

[seesy1234]

do u think that the RX &TX are useless cause the PIC also can control the motor and to record.so y still need RX&TX?i don't have RX&TX cause i lecture told me that our country don't sold its..do you have any website about how to record data into PIC?