[Project] Frankencooper

[DemonicSandwich]

Project Frankencooper.
(Because it was built from the corps's of other dead RC cars.)

I wanted to modify this RC car I had lying around. This thing is made out of what must be the most brittle plastic on the planet.
I have repaired it several times mostly reattaching and reinforcing parts with hot glue. But out of all my RC vehicles, it is the only one left working.

My goal is to make it into an Obstacle Avoiding Robot while still keeping the ability of radio control. Might also give it a line following ability of I have enough IC pins left.
It used to run on 3 AA batteries. I will make it run off of a single cell Lithium Polymer battery instead.

Checklist: [☒]Not started., [☐]Started, not complete., [☑]Complete

• [☐]Build battery charge circuit.
• [☑]Modify LiPo pack.
• [☑]Grind out battery bay.
• [☑]Install IR sensors on car body.
• [☑]Build Motor Drivers.
• [☑]Build Sensor Board.
• [☑]Program Motor Driver.
• [☑]Program Sensor Board.

The victim:

[neodos]

Hey man sounds like a pretty cool project!

You might wanna check this out: http://www.arduino.cc/

[DemonicSandwich]

I'm gonna be using a PIC microcontroller for this.

[DemonicSandwich]

Ok, after a setback (which was fixed) I am back on track for this project.

The battery was the first to arrive and as such was the first to be modified.
The battery pack was originally a 2S1P (1 two cell string) 7.4v (8.4v full) 500mAh battery. Since the car originally ran off of 3 AAs(4.5v new) this pack voltage was far to high.
So I reconfigured the pack into 1S2P pack. (3.7v, 1Ah)


Original: (7.4v 500mAh)


New: (3.7v 1Ah)

[nintendo9713]

Looks like a nice little project. I've always used Arduinos as the μC of choice. $30, you can't go wrong. I just got one in recently with a WAV shield so I can make something for a prank

[DemonicSandwich]

Ya, I wanted to get into micro controllers for some time. But back in October I had the choice of getting new batteries for my plane or programming hardware for μC's.
I came to the realization that I suck at flying the damn thing and hate having to fix it every time I crash, which is to say every time I fly it.
So I got the μC hardware instead. Happened to choose PIC brand because of the overwhelming support available for them.

==================================================

Ok, so I finished the control board today. It is the board that controls the steering motor and drive motor. I made the mistake of not removing the flux from the top mini-board there so it looks like shit.

Also, I am never making a custom PCBoard with only through-hole parts again.
The good quality drill bits of that size(<1mm diameter) are expensive and the cheap ones(which I have) are shit and bend easily when used.
Surface mount parts are way easier to work with for me. Also way cheaper than through-hole parts.

------------------------------------------------------------
This board use two h-bridges to control the two motors of the car. The h-bridge(the mini-board, top-left) for the drive motor uses MOSFETs to make it more efficient.
As it turns out, using the FETs and a more powerful battery has given it more than a 50% increase in power. I actually have to use PWM to decrease the speed to something controllable but will leave in a switch to allow full speed when I want.

The other h-bridge (bottom) controls the steering motor. It is by no means efficient but thankfully the steering motor doesn't use much.

[Click16]

Did you literally draw your PCB?

Looks like some sharpie marker traces...

[DemonicSandwich]

Did you literally draw your PCB?

Looks like some sharpie marker traces...

That is exactly what I did.

[xxpenguinxx]

You should get some neodymium magnets for that motor, or just find an XMOD gen 1 motor kit.

[Click16]

That is exactly what I did.

[nintendo9713]

Looks nice though. I'll try to check in weekly to see how it comes. I'm currently enrolled in a Computer Architecture course at my university and for our project, we are using an RFID reader. Once scanned, it is sent to "The Boss" via a phone application (probably iPhone since my partner specializes in that stuff, I'm more hardware >_<), but you can choose to open the entrance to the work building. If Yes is selected, I'll use a simple motor to open and close the door. Really simple but I"m sure it'll suffice.

[DemonicSandwich]

Aaaand Sensor board complete and battery bay ground down to fit the new battery.
Turns out the new battery fits perfectly in the space where 2 AA cells used to be.

I also installed programming ports so I can easily change the code without having to dismantle it.
That switch inside the battery bay is a Max Speed selector.
With it I can (when I program it to anyway) change the max speed of the drive motor between 50% and 100% power.
(when 100% it will do doughnuts on the kitchen floor)

Now I just need to install the sensors and program the thing.

[nintendo9713]

Looks nice! Definitely one thing I'm lacking in is PIC programming. We always use Basic Stamp, Arduino, or mBed at my university. Or these badass cyclone boards :3

[OwnZ joO]

Starting to look pretty sexy demonic

[rentreg]

add a camera and C4.

[DemonicSandwich]

Whoa nintendo, that's a huge board.
-------------------
For the last day our two I've been troubleshooting my sensor board. I kept getting incorrect voltage readings on the amplifier. All the traces checkout out fine.

As it turns out, even though the port pin that would be reading that sensor voltage is an analog input, the internal pull-up for that pin was still enabled.
Amazing how a single bit can derail something.

Anyway, I installed the IR emitters, radio receiver, headlamps, and most of the wiring for the sensors on the car body. (pictures after sensor installation)
I also changed the setup for the amplifier(which is now buffer) so that it uses less parts and the sensors are sensitive at longer ranges. (about 5-8 inches)

[DemonicSandwich]

Ok. Installing the sensors was one of the most aggravating parts of this project. They weren't hard to install.
They were difficult to work with because they have a symmetrical, solid black, component package.
Other than one pin being slightly longer, there is no way to tell what pin it what when they are cut to length.
So I ended up installed two of them backwards and had to tear them out and reinstall them.
After screwing up two sensors, I began coloring one pin black with a Sharpie to ensure they didn't get mixed up.

There are a total of 6 sensors on the car: one rear sensor, two side sensors, and 3 forward sensors with one straight forward, the other two set about ±30° from center.

I have not yet made the connector for the radio's control signals nor do I intend to code the receiver functions in yet.
I'ma gonna to right to making it drive around.

[xxpenguinxx]

Looking good Demonic! The car looks very clean.

[nintendo9713]

Agreed, it's looking nice!

[DemonicSandwich]

Ok. I coded some of it.

Now it surveys it's surroundings, then starts driving. But so far that's all I have for now.
It's a clusterfuck of Conditional Programming.

[troymac1ure]

I can't wait for the video
Looks pretty cool DS.

[Gary]

Indeed it does look cool.

Looking forward to seeing how it drives.

[DemonicSandwich]

I coded the starting loop to get the car moving. I did so from imagination and that shit was hard to think through.

So I made a flow chart for the Main Loop and Reverse and Turn loop.



Other than some editing of the code and adding the radio connector, the project is basically done.

The battery charge board is still marked as "In Progress." The main portion of the circuit is on a breadboard but it won't go beyond that since in two weeks I'll have to toss the batteries in the trash before I leave.

No need to have volatile lithium batteries left around my technologically ignorant family.
Last thing I need is for them to put my shit in the shed and burst into flames on a hot day because they didn't know the batteries were in there.
(won't loose much, they only cost $4.30 each)

I'll try to get some video of it sometime.

[DoorM4n]

You are doing something so unbelievably cool! I hope it turns out really well! And I appreciate you posting pictures of your progress. I enjoy seeing your developments! Keep it up!

[DemonicSandwich]

Pow.

Radio control was implemented and I can take control of it at any time just by using the transmitter. When in radio control mode, it drives 2.5x as fast.

When it reaches a wall, it reverses for a set time period to get some space.
Then checks both sides, and if it finds both sides unblocked, it picks a random direction and drives that way.
This it why it seems a bit retarded at times and drive back into the wall it turned away from.