Hello guys, it's been some time I'm no longer doing much with calculators, but I'm still programming quite a lot. Currently I'm building a telescope with some class mates and I'm writing the software for its control. We use a Pi B+ to manage everything but since it doesn't have its own clock I figured I'd buy an RTC module. The project is almost due though so getting the Adafruit one for the Pi would have taken too long so I bought one at a local store, a DS1302 (http://www.okaphone.com/artikel.asp?id=472987, sorry for the dutch). It's originally for the Arduino I believe, but I followed this guide to use it with my Pi: http://raspberrypi.stackexchange.com/questions/12310/would-it-be-possible-to-use-the-ds1302-made-for-arduino
It now works in the sense that I can set the time and read from it, but I've encountered a major problem: the clock doesn't seem to "tick" when unplugged from the Pi. It remembers the time it had before disconnecting though, so I don't believe the battery is dead. In the datasheet I found http://datasheets.maximintegrated.com/en/ds/DS1302.pdf I found something about a clock halt flag, but I'm not sure if that's it or how to fix it.
Is anyone familiar with this (type of) clock and could help me fix it? It would greatly ease the user experience
So I purchased Mario Kart 8 recently and it comes with a free game. The games I can choose from are:
Nintendo Land
New Super Mario Bros U
Game & Wario
Pikmin 3
Windwaker HD
Sonic: Lost World
Mario & Sonic at the Olympic Wintergames (not gonna choose this )
Wii Party U
The Wonderful 101
Monster Hunter Tri Ultimate
I already have NL, NSMBU and Pikmin 3. The Windwaker HD looks interesting, but I already have the GC one. My real doubt is between Sonic and Monster Hunter. What would you guys pick?
I'm trying to make a two body simulation, but it doesn't seem to work Plotting x vs y should be circular or elliptical right? Am I choosing the wrong starting conditions or is my way of doing it just wrong?
''' from __future__ import division import math import matplotlib.pyplot as pyp import numpy as np
# Gravitational constant (N*m^2*kg^-2) G = 6.674e-11 # A giga year in seconds. gyrts = math.pi * 1e7 * 1e9
def Fgrav(M, m, r): ''' Gravitational force of two bodies attracting each other. ''' return -G * M * m / r**2
# Solar mass (kg) M = 1.989e30 # Earth mass (kg) m = 5.9721e24
# Initial conditions. # Position (m). x, y = 150e9, 0 X, Y = 0, 0
# Velocity (m/s). vx, vy = 0, 30e3 Vx, Vy = 0, 0
time = 5*math.pi*1e7 t = 0 dt = 1000 xarr, yarr, rarr, tarr = [], [], [], [] while t < time: # Update the positions. x += vx * dt y += vy * dt # Calculate the separation vector. dx = x - X dy = y - Y r2 = dx*dx + dy*dy + 1e-4 r = np.sqrt(r2) #print 'dx, dy: ', dx, dy # Calculate components of the gravitational force. fgrav_x = Fgrav(M, m, r) * dx / r fgrav_y = Fgrav(M, m, r) * dy / r #print 'Fgrav: ', fgrav_x, fgrav_y # Update the velocities. vx += (fgrav_x / m) * dt vy += (fgrav_y / m) * dt Vx += (fgrav_x / M) * dt Vy += (fgrav_y / M) * dt #print 'vx, vy: ', vx, vy
X += Vx * dt Y += Vy * dt
# Store all data. xarr.append(dx); yarr.append(dy); rarr.append(r) tarr.append(t)
#include <os.h> main: .global main push {r4-r11, lr} bl lcd_ingray bl clrscr ldr r0, =0xC0000010 ldr r0, [r0] mov r2, #8 adr r1, sprite add r0, #200@ x add r0, #SCREEN_WIDTH/2 * 80@ y draw: ldr r3, [r1], #4 str r3, [r0] add r0, #SCREEN_WIDTH/2 subs r2, #1 bne draw@ if there are lines left, draw the next one bl wait_key_pressed mov r0, #0 pop {r4-r11, pc} sprite: .word 0x00000000, 0x00000000, 0x00FFFF00, 0x00FFFF00, 0x00FFFF00, 0x00FFFF00, 0x00000000, 0x00000000 This is probably a stupid question, but the problem I'm facing is that I can only use x coordinates that are a multiple of 4. What would I need to do to be able to use any number for the x coordinate?
Since about two days ago my laptop started acting a bit weird. Now and then it just scrolls to the top of the window and won't let me scroll down anymore. It's usually fixed by pressing the scroll lock button once or twice (which also happens to be the num lock button, so it's rather annoying) so I'm assuming it's a problem with scroll lock turning itself on automatically or something. I have no clue what this is or how to fix it.
My school is getting rid of old PCs so I'm taking them whenever they appear. I'll be keeping a little list (I name them after galaxy clusters) of them and I'm wondering what to put them to use for (server is not an option since I'm not allowed to leave them on 24/7 or I'll have to pay bills as well). I was thinking of maybe (once there are more) hooking them up together and make a little cluster to do Blender stuff on or something.
Pandora CPU: PentiumD @ 3.00GHz fried it RAM: 4x 2GB DDR2 Kingston GPU: nVidia 6600 (not sure which one yet) HDD: Western Digital Caviar 80GB
I know it's not very calc related but it fits science and had some programming in Awk and Python As some of you may have heard or seen I've had an observation project for my astronomy class. It has driven us crazy many times but finally it's finished and a report has been made. It's my first scientific report so if you read it, criticism is welcome Without further ado:
Welcome to my scrapyard. I have not stopped with ARM, I'm just picking up real life again since my study's second year is about to start. Progress will be much slower and updates may become rare(r), so I guessed I'd post what I've done so far. It's not much and by far good, but maybe it's useful to somebody or something.
#include <os.h> @ r0: screen address @ r2: counter @ r3: address of sprite address @ @ main: .global main push {r4-r11, lr}@ push link register on the stack bl lcd_ingray bl clrscr ldr r0, =0xC0000010@ screen address ldr r0, [r0]@ put the address of the screen address in r0 mov r2, #8@ counter adr r1, sprite@ store the address of sprite in r1 adr r4, sprite2 add r0, #200 add r0, #SCREEN_WIDTH/2 * 160 mov r5, #40 draw: ldr r3, [r1], #4@ load whatever is on the address contained in r1 in r3 @ r1 contains the address of sprite, so r3 will contain @ the nth word of sprite data str r3, [r0], #8@ draw a line to the screen ldr r3, [r4], #4 str r3, [r0], #-8 add r0, #SCREEN_WIDTH/2@ move to the next line subs r2, #1@ counter count down bne draw@ if there are lines left, draw the next one bl wait_key_pressed mov r0, #0 pop {r4-r11, pc}@ return 0 and pop everything back sprite: .word 0x00000000, 0x00000000, 0x00FFFF00, 0x00FFFF00, 0x00FFFF00, 0x00FFFF00, 0x00000000, 0x00000000 sprite2: .word 0x00FFFF00, 0x00FFFF00, 0xFF0000FF, 0xFF0000FF, 0xFF0000FF, 0xFF0000FF, 0x00FFFF00, 0x00FFFF00
#include <os.h> @ check http://hackspire.unsads.com/wiki/index.php/Keypads for keypad info main: .global main push {lr} bl lcd_ingray bl clrscr ldr r0, =0x900E0010@ keypad data address check: ldrh r1, [r0, #14]@ load the first half word into r1 tst r1, #1 << 9@ check for a keypress (ctrl here), a keypress clears a bit bne end@ if the bit is not cleared (no keypress) branch to check b check@ else end the program end: mov r0, #0 pop {pc}
Stuff that resembles a program Stone age text editor (most likely written terribly, can throw errors because of this)
@ handle special keys spacekey: adr r0, off ldr r1, [r0] add r1, #4 str r1, [r0]
add r11, #4 bl wait_key_pressed b keycheck delkey: @ set the screen pointer back one step sub r10, #4 sub r11, #4 @ set the offset back one step adr r0, off ldr r1, [r0] cmp r1, #0 subne r1, #4 str r1, [r0]
@ store emptyness at the characters place ldr r0, =0xFFFFFFFF mov r1, #8 drawdel: str r0, [r10] add r10 ,#SCREEN_WIDTH/2 subs r1, #1 bne drawdel bl wait_key_pressed b keycheck enterkey: ldr r0, =SCREEN_WIDTH/2 * 9 ldr r1, off sub r0, r1 add r11, r0
adr r0, off mov r1, #0 str r1, [r0]
bl wait_key_pressed b keycheck ctrlkey: b end end: mov r0, #0 pop {r4-r11, pc}
@ Sprites; pixels go lik 0x78563412 !!!! @ for some reason letter_z only works if it is located above letter_y
I've been trying to have some sort of text input with ARM now but I've hit a wall at this point. I've implemented enter/newline continuing at the same x position and also managed to get it back to the start of the line. The problem I have is incorporating the delete/backspace functionality. The code below shows how I imagined it to go, but this makes enter act all funky and weird, offsetting the letters from the right by the amount of characters deleted. When uncommenting the commented code in delkey the program will not even build, resulting in an error message "149: Error: invalid constant (408) after fixup".
@ handle special keys spacekey: adr r0, off ldr r1, [r0] add r1, #4 str r1, [r0]
add r11, #4 bl wait_key_pressed b keycheck delkey: @ set the screen pointer back one step sub r10, #4 sub r11, #4 @ set the offset back one step @adr r0, off @ldr r1, [r0] @cmp r1, #0 @subne r1, #4 @str r1, [r0]
@ store emptyness at the characters place ldr r0, =0xFFFFFFFF mov r1, #8 drawdel: str r0, [r10] add r10 ,#SCREEN_WIDTH/2 subs r1, #1 bne drawdel bl wait_key_pressed b keycheck enterkey: ldr r0, =SCREEN_WIDTH/2 * 9 ldr r1, off sub r0, r1 add r11, r0
adr r0, off mov r1, #0 str r1, [r0]
bl wait_key_pressed b keycheck ctrlkey: b end end: mov r0, #0 pop {r4-r11, pc}
I'm playing around a bit with keypresses and wanted to put something together with it. It's a very simple idea: detect a keypress, branch to the appropriate label, do your thing and branch back to the keypress detection loop. In my attempt below the ctrl key exits the program and the enter key branches to another part. My problem is that this branch stays, when it goes back to the keypress detection loop (at least I think it does), it keeps branching to the part where the enter key points to. Have I misunderstood something about ARM or am I doing something wrong codewise?
I want to take a dive in the deep and dark depths of the nspire and learn to do stuff with assembly. I figure the way to start would be to learn to work with ndless and C, but for assembly I have no clue where to start or even how.
I had eric set up on my windows pc, but lost it during a some maintenance. Now I'm trying to get it back, but I just don't know how anymore. Does anyone have a clear tutorial on what to do (like how to install sid, because there is no exe )? Because I'm pretty lost and confused now :'(
I have a problem with the alignment of my elements. I want to have a centered area like on the omni homepage but without the side stuff. The problem i have is that it works fine if I turn off the float property, but then it slips behind the menu bar All code can be found here: https://github.com/ElementCoder/astro
Edit: this is fixed now, I left out the float: left part and added <br style="clear: both;"/> below the div of the menubar.
So I don't know if this thread will even live for more than a week, but I'll try to gather some simple yet fascinating (in my opinion at least) facts about astronomy and the universe. It'll probably (not yet) be very high level complicated stuff, but that will come later. So yeah, if anyone has some questions you can always ask and I'll see if I can help you out (of course you can help too ). Note: throughout these derivations you may think "why is he doing that?" or "why does he discard that?". The reason is because we make a few simple assumptions that make our lives a whole lot easier. Stars, matter clouds and galaxies for example are all 'perfect spheres'; stars are only hydrogen (though that may vary depending on what I'm derivating / showing).
Gravitational Collapse: Condition 1: The cloud is larger than its Jeans length
Spoiler For Jeans length for a 3 dimensional cloud:
Condition 2: The cloud is heavier than its Jeans mass
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I'm no longer doing much with calculators, but I'm still programming quite a lot. Currently I'm building a telescope with some class mates and I'm writing the software for its control. We use a Pi B+ to manage everything but since it doesn't have its own clock I figured I'd buy an RTC module. The project is almost due though so getting the Adafruit one for the Pi would have taken too long so I bought one at a local store, a DS1302 (http://www.okaphone.com/artikel.asp?id=472987, sorry for the dutch). It's originally for the Arduino I believe, but I followed this guide to use it with my Pi: http://raspberrypi.stackexchange.com/questions/12310/would-it-be-possible-to-use-the-ds1302-made-for-arduino
)
Plotting x vs y should be circular or elliptical right? Am I choosing the wrong starting conditions or is my way of doing it just wrong?
