How do I give a radio control car autonomous control

[Byte_Butcher]

Well, I see it's already too late to edit my original post (sigh), but I didn't want to give the wrong impression when I said I hated EagleCAD..

I'm sure it's a fine program, and I know a LOT of folks use it and love it.

I just found it to be rather... unfamiliar.. compared to other programs I've used, and I found it difficult and non-intuitive (to my brain) to learn.

I stumbled across DipTrace one day and found it to be much more to my liking.

Anyway, I didn't want to sound like I was bashing EagleCAD. I used it long enough to realize it's a good program... I just didn't like the way it felt. It's just a personal preference thing.. like what's yer favorite color.

steve

[Kenjones1935]

steve, thank you for your direct control suggestion.

My thought is to hack into the present connection between the RC receiver and the ESC for the drive wheels. I figured with a DPDT switch I could toggle the two wires that are presently connecting the receiver to the ESC (the third wire is ground) between their present state and the PIC. Two wires, one DPDT switch. The red wire is PWM signal. The white one is Vcc. (Actually I think I should leave the white wire floating. Let the ESC use its own power to interpret the PWM signal.) Good idea? No? Insert a diode?

The RC receiver gets its Vcc and gnd from the ESC. My ancient Triplett multimeter tells me that this Vcc is +5v. I know the battery is +7.2v. The ESC must have a 5v regulator on board.

The other DPDT switch is needed to perform much the same operation on the Vcc and signal wires between the receiver and the steering servo motor. In this case the white Vcc wire is driving from the receiver. This one I will switch and drive from the PIC when it is in control.

Thus when the PIC is in control the RC receiver's 5v comes from the
PIC. When the third RC channel signal commands return to RC control the PIC will interpret that and flip the DPDT switches back.

I have this on paper drawn by a #2 pencil. Unreadable by anyone but myself. I'll make you guys a schematic. That may take a couple days. I will be distracted tomorrow and I need to learn about CAPTURE ( I have a bootleg copy. I have to give it a try.)

Ken

[Kenjones1935]

Anybody using CAPTURE for schematics? I am trying, but I have been hit for a loss. I need the library file for the Microchip PIC16F887. I found just that at:

http://f1.grp.yahoofs.com/v1/cKwuS-E...w/PIC16F88.OLB

Trouble is when I download the file and try to open it with CAPTURE, the error window pops up saying: "Unable to load file 'C:\ORCADWIN\CAPTURE\LIBRARY\PIC16F88.OLB'. Object Not Found."

The file really is there. I can open it with NOTEPAD, but a lot of good that is...

Ken

[Kenjones1935]

I received in the mail yesterday a booklet that mentioned the WowWee product Rovio. They have done what I am planning. They have a BOT which accepts external commends (via WIFI) and also runs autonomously. Interesting.... Not as sexy as my idea (IMHO)

http://www.wowwee.com/en/products/te...ce/rovio/rovio

I'm little by little making a schematic using ORCAD's CAPTURE product.

I am working on my idea not in complete electronic detail. My first picture will include all significant pieces, all connectors, all multi-conductor wires and my best guess as to which piece goes on which prototype board.

This will give me enough of a concept to take to my local RC Cars establishment and to Do It Yourself Electronics. After that the transistors', resistors', capacitors' batteries' and PIC pin selection details will be created.

Thanks for your continued interst.

Ken

[mackrackit]

Looking forward to hearing more and seeing the pictures.

[Kenjones1935]

Attached below is my first try at which parts go where on my radio controlled car. I drew it with a Tee square and triangles. (I could not stick a thumbtack into our oak cutting board? Drawing boards were made of maple - I think)

The parts in the red section are originally in the car.

The blue section is hoped to be on the PICkit 2. (There is an added toggle switch which I may or may not be able to solder to that printed circuit.)

The yellow section is two sonic range control units each on its own fairly small pc card. I need to devise a method to attach them to the car plus an electrical connection method.

The rest, in black, is presumed to fit onto an inline prototype card.

A big issue is the connectors. The more the better if I can make them reliable. I welcome your judgments.

I have not included electronic details. I think I know which PIC pins to use. The three different Vdd sources (USB supplied, 6 volt battery pack and 7.2 volt battery pack) boggle my mind. If I can settle on a physical layout then resisters, capacitors, and transistors will be next.
I need to figure out how to trigger PIC interrupts from the light sensor and the sonic range control.

HAPPY NEW YEAR.

[Kenjones1935]

More details.

Originally the pulse width modulated signals from the radio receiver control the steering servo motor and the amplifier (speed control) which drives the DC motor.

My design has the PIC interrupting that service by controlling the multiple double pole double throw relay switches.

Channel 3 from the radio receiver be used to tell the PIC to toggle between autonomous control and radio control. This decision can be overridden with the toggle switch in the middle of the picture.

Once in autonomous control the car has two means of evaluating its environment. A narrow angle lense (the cardboard tube from a toilet paper roll?) light sensitive device and two sonic range control devices.

The light sensor could find a incandescent light bulb. Once found (by turning in a 360 degree circle for example) a simple line following algorithm should lead the car to the light source.

The front and right side mounted sonic range controls could guide the PIC counter clockwise around the inside of a room. This idea is on the WEB at:

http://letsmakerobots.com/node/928

Thanks all,

Ken