[melcus]

Hi,
So I finally got myself into organisated to create my first rc tractor and I was going to use a siku Massey Ferguson 8680.
I have used the same basic design you used (one Arduino in cab for radio, one Arduino in body for drive, steering), and wrote my own code.
For the drive I was going to use 2 N20 motors and for steering and front and rear hitches I was going to use 3 servos.
So I wired everything on a breadboard and after a lot of messing around got everything working.
Then I got out the 8680 and realised things just aren’t going to fit.
The body chassis is only about the width of one N20 motor never mind 2.
I could cut a hole in each side of the chassis and have the motor sticking out a bit, the rear wheels would be out a bit but it could be ok, but then I realised the screw that holds the back end of the tractor together and the slot for the rear hitch are in the position I would be putting the drive motors.
I am also concerned about the servos for steering and the hitches, I thought I had gotten small servos but looking at them now, they seem kind of big to fit inside the body. I am guessing the servo for the steering would fit under the bonnet if I cut away part of the plastic engine?, is there enough room for a second servo for the front hitch there, if not I can live without a working front hitch but I would like to have the rear hitch working.
So basically I am looking for a bit of advice on how to fit the components inside the tractor, when I have created stuff with arduinos before it wasn’t in such a confined space (model farms) so this is new to me.

Thanks
Mel

[melcus]

Hi
So I have been looking into expansion chips and I found pcf8591 it looks like the kind of thing I would need to read the input from a potentiometer and control a servo. It has 4 inputs and 1 output so not the perfect ratio but it saves on extra arduinos should still be good.

Thanks
Melcus

[melcus]

Hi,
Version 1 of the model farm only used one Arduino with long wires running round the model for the leds and servos and it used all the ports on the Arduino.
So for version 2 I am adding a few more servos for doors and I was also going to try one (or more) stepper motors to try and get cows moving on a conveyor belt ( a bit ambitious I know ) and maybe a water pump to move coloured water in a slurry pit ( not completely sure about this bit ) so I need more ports which is why I thought I would need more Arduinos, I am new to the whole electronics scene so I didn’t know anything about I/o expansion chips, but looking at what you suggested they seem like a good idea.
I just have a couple of questions, I have seen examples where you can use a PCF8574 to turn on leds and also to accept input from a button, but can it also be used to control a servo or read the input from a potentiometer?
Even if they don’t I should still be able to make good use of them.

Thanks
Melcus

[melcus]

Hi,
Thanks for that, slightly embarrassing that I don’t know where my decimal point goes, but to make matters worse I realised I was using a .01 uF capacitor rather than .1. Anyway change of capacitor and resistors and I now have a flashing led.

Thanks
Mel.

[melcus]

Hi,
The battery/FTDI cable is connected to Vcc and battery is only 3.7v so you could be right about it just not getting enough power. I will get a bigger battery and try again.

Thanks
Melcus

[Author]

Posts