French FX-7 robot
Projects | |
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Participants | Mi1es |
Skills | Electronics, Soldering, Programming, Creative thinking |
Status | Active |
Niche | Electronics |
Purpose | World domination |
"Contrôle système! Contrôle système!"
Contents
Overview
System
Direct Drive control via RaspPI
Machine has been taken apart.. blblblalbla
H-bridge board has all the transistors of the original board on it for 4 full H-bridges that can drive all of the four bi-directional motors.
Original 'direct drive' Layout was as follows , with the connectors of the motors facing you:
- First block, gpio18, w1, gpio4, w7, Left tread
- Second block, gpio17,w0, gpio23,w4, Right treads
- Third block: gpio27,w2, gpio22,w3, hip
- Fourth block: gpio24, w5, gpio25,w6, arms
'Direct Drive' Python code
import RPi.GPIO as gpio import time import pygame from pygame.locals import * gpio.setmode(gpio.BOARD) gpio.setup(7, gpio.OUT) gpio.setup(11, gpio.OUT) gpio.setup(13, gpio.OUT) gpio.setup(15, gpio.OUT) gpio.output(7, True) gpio.output(11, True) while True: gpio.output(13, True) gpio.output(15, False) time.sleep(2) gpio.output(13, False) gpio.output(15, True) time.sleep(2)
pygame.init() screen = pygame.display.set_mode((640,480)) pygame.display.set_caption("Pygame") pygame.mouse.set_visible(0) done = False enable = 0 direction = 0 while not done: for event in pygame.event.get(): if(event.type==KEYDOWN): print event if(event.key==273): direction=1; enable=1; if(event.key==274): direction=-1; enable=1; if(event.type==KEYUP): print event if(event.key==273): direction=0; enable=0; if(event.key==274): direction=0; enable=0; if(enable==1): if(direction==1): print "Forwards" gpio.output(13, False) gpio.output(15, True) if(direction==-1): print "Backwards" gpio.output(13, True) gpio.output(15, False) else: gpio.output(13, False) gpio.output(15, False)
With this code-shim you can test the function of your code even without having RPi.GPIO loaded (like on most PC's)
Note it doesnt implement all things yet; but enough to work for this project currently.
Working on a shift-register help-library
class FAKEGPIO: def __init__(self): self.BOARD=1 self.OUT=0 self.IN=1 def setmode(self,variant): print "Call: setmode: variant -> " + str(variant) def setup(self,pin, type): print "Call: setup : pin -> " + str(pin) + ", type -> " + str(type) def output(self,pin,state): print "Out:" + str(pin) + "-> " + str(state) gpio = FAKEGPIO()
Shift-Register driving of robot
Since the RaspPI doesnt have much IO and the robot requires 8 output-pins just for the basic motor-control already, we've started looking at driving the outputs using shift-registers instead.
The proto-board has been re-wired to have two shift-registers hosted on it, connected in series, for a total of 16 outputs.
The motor-pins are connected to the first of the two shift-registers; this means that the last 8 bits of data shifted into the 16 bit register-space controls the motors as the first bit shifted in ends up being at the last-most position after 16 clock-cycles.
Shift-register layout
Shift-register layout | Register | Bit | Motor | Direction | |||||
---|---|---|---|---|---|---|---|---|---|
1 | 0 | Left Tread | Forwards | ||||||
1 | Left Tread | Backwards | |||||||
2 | Right Tread | Forwards | |||||||
3 | Right Tread | Backwards | |||||||
4 | Hip | Forwards | |||||||
5 | Hip | Backwards | |||||||
6 | Arms | Open | |||||||
7 | Arms | Close | |||||||
2 | 0 | TBD | TBD | ||||||
1 | TBD | TBD | |||||||
2 | TBD | TBD | |||||||
3 | TBD | TBD | |||||||
4 | TBD | TBD | |||||||
5 | TBD | TBD | |||||||
6 | TBD | TBD | |||||||
7 | TBD | TBD |