Recently discovered that internal build in clock is quite unstable. Making a simple stopper was quite unsharp.
Added external clock (25Mz) and the picture is much better.
Category: Linux
(Arduino -> Atmega328P) + RTC + MCP23008 + LCD = kell
Tuli tahtmine kella ehitada.
Vanast ajast oli olemas LCD 16X4, RTC ja arduino R3
Ullult olin soetanud LCD expanderi – https://taaralabs.eu/lcd-plug/
RTC annab kella võimaluse. Kui toide välja võtta, siis kenasti tiksub edasi ja hoiab kellaaega õigena.
MCP23008 – annab vabaks hulga arduinio porte, vastasel juhul poleks ilmselt RTC ka kuhugi panna.
Hetkel selline laiali prototüüp, kes teab kas see kuhugi kaugemale jõuabki.
Koodiosa tuleb kõvasti tuunida, hetkel suht häbi selle osa üle.
Näiteks on nädalapäev ühe päeva võrra nihkes.
Esimene versioon tõesti halba koodi – https://github.com/margusja/ArduinoRTC
Osa2
Kuna kogu arduino plaati ühe kella alla matta on minu jaoks liigne luksus, siis otsustasin selle osa eraldi Atmega328P kätte anda. Alguses oli plaan ilma välise kellata, aga hetkel on siis välise 16MH kellaga.
Ühendasin ISP atmega328P’ga:
Allikas: http://upvector.com/atmega/
Minul sai selline asi. Programmaator on mul avrispmkII
Ja oh seda õnne:
margusja@IRack:~/Documents/Arduino/hardware/breadboard/avr$ avrdude -c avrispmkII -v -p ATMEGA328P -P usb
avrdude: Version 5.11.1, compiled on Feb 12 2013 at 01:24:54
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2009 Joerg Wunsch
System wide configuration file is “/usr/local/CrossPack-AVR-20130212/etc/avrdude.conf”
User configuration file is “/Users/margusja/.avrduderc”
User configuration file does not exist or is not a regular file, skipping
Using Port : usb
Using Programmer : avrispmkII
avrdude: usbdev_open(): Found AVRISP mkII, serno: 000200133546
AVR Part : ATMEGA328P
Chip Erase delay : 9000 us
PAGEL : PD7
BS2 : PC2
RESET disposition : dedicated
RETRY pulse : SCK
serial program mode : yes
parallel program mode : yes
Timeout : 200
StabDelay : 100
CmdexeDelay : 25
SyncLoops : 32
ByteDelay : 0
PollIndex : 3
PollValue : 0x53
Memory Detail :
Block Poll Page Polled
Memory Type Mode Delay Size Indx Paged Size Size #Pages MinW MaxW ReadBack
———– —- —– —– —- —— —— —- —— —– —– ———
eeprom 65 20 4 0 no 1024 4 0 3600 3600 0xff 0xff
flash 65 6 128 0 yes 32768 128 256 4500 4500 0xff 0xff
lfuse 0 0 0 0 no 1 0 0 4500 4500 0x00 0x00
hfuse 0 0 0 0 no 1 0 0 4500 4500 0x00 0x00
efuse 0 0 0 0 no 1 0 0 4500 4500 0x00 0x00
lock 0 0 0 0 no 1 0 0 4500 4500 0x00 0x00
calibration 0 0 0 0 no 1 0 0 0 0 0x00 0x00
signature 0 0 0 0 no 3 0 0 0 0 0x00 0x00
Programmer Type : STK500V2
Description : Atmel AVR ISP mkII
Programmer Model: AVRISP mkII
Hardware Version: 1
Firmware Version Master : 1.23
Vtarget : 5.1 V
SCK period : 8.00 us
avrdude: AVR device initialized and ready to accept instructions
Reading | ################################################## | 100% 0.01s
avrdude: Device signature = 0x1e950f
avrdude: safemode: lfuse reads as FF
avrdude: safemode: hfuse reads as DE
avrdude: safemode: efuse reads as 5
avrdude: safemode: lfuse reads as FF
avrdude: safemode: hfuse reads as DE
avrdude: safemode: efuse reads as 5
avrdude: safemode: Fuses OK
avrdude done. Thank you.
Part 3
Peale juhtmete ümbertõstmist ja uue kivi programmeerimist on pilt ikka segane, aga arduino sai vahelt minema.
Kuna on plaanis kivil lock bitte ja fuses muuta, siis tundub, et siinkohal on ka õige praegused setingud maha kirjutada
avrdude -c avrispmkII -v -p ATMEGA328P -P usb -U lfuse:r:-:h -U hfuse:r:-:h -U efuse:r:-:h
Reading | ################################################## | 100% 0.00s
avrdude: writing output file “<stdout>”
0xff
avrdude: reading hfuse memory:
Reading | ################################################## | 100% 0.00s
avrdude: writing output file “<stdout>”
0xda
avrdude: reading efuse memory:
Reading | ################################################## | 100% 0.00s
avrdude: writing output file “<stdout>”
0x5
avrdude: safemode: lfuse reads as FF
avrdude: safemode: hfuse reads as DA
avrdude: safemode: efuse reads as 5
avrdude: safemode: Fuses OK
Ja ega ma neid peast ei arvuta – http://www.engbedded.com/fusecalc/
Part 4.5 – Asja lihtsustamiseks võtsin kasutusele sisemise kella (avrdude: safemode: lfuse reads as C2).
Nüüd on prototüüp võimalikult lihtne.
bash shortcuts
No ei jää meelde. Seega endale siia väike spikker.
Moving the cursor:
Ctrl + a Go to the beginning of the line (Home) Ctrl + e Go to the End of the line (End) Ctrl + p Previous command (Up arrow) Ctrl + n Next command (Down arrow) Alt + b Back (left) one word or use Option+Right-Arrow Alt + f Forward (right) one word or use Option+Left-Arrow Ctrl + f Forward one character Ctrl + b Backward one character Ctrl + xx Toggle between the start of line and current cursor position
Editing:
Ctrl + L Clear the Screen, similar to the clear command Alt + Del Delete the Word before the cursor. Alt + d Delete the Word after the cursor. Ctrl + d Delete character under the cursor Ctrl + h Delete character before the cursor (backspace) Ctrl + w Cut the Word before the cursor to the clipboard. Ctrl + k Cut the Line after the cursor to the clipboard. Ctrl + u Cut/delete the Line before the cursor position. Alt + t Swap current word with previous Ctrl + t Swap the last two characters before the cursor (typo). Esc + t Swap the last two words before the cursor. ctrl + y Paste the last thing to be cut (yank) Alt + u UPPER capitalize every character from the cursor to the end of the current word. Alt + l Lower the case of every character from the cursor to the end of the current word. Alt + c Capitalize the character under the cursor and move to the end of the word. Alt + r Cancel the changes and put back the line as it was in the history (revert). ctrl + _ Undo TAB Tab completion for file/directory names
For example, to move to a directory ‘sample1’; Type cd sam ; then press TAB and ENTER.
type just enough characters to uniquely identify the directory you wish to open.
History:
Ctrl + r Recall the last command including the specified character(s)
searches the command history as you type.
Equivalent to : vim ~/.bash_history.
Ctrl + p Previous command in history (i.e. walk back through the command history)
Ctrl + n Next command in history (i.e. walk forward through the command history)
Alt + . Use the last word of the previous command
Ctrl + s Go back to the next most recent command.
(beware to not execute it from a terminal because this will also launch its XOFF).
Ctrl + o Execute the command found via Ctrl+r or Ctrl+s
Ctrl + g Escape from history searching mode
Process control:
Ctrl + C Interrupt/Kill whatever you are running (SIGINT)
Ctrl + l Clear the screen
Ctrl + s Stop output to the screen (for long running verbose commands)
Ctrl + q Allow output to the screen (if previously stopped using command above)
Ctrl + D Send an EOF marker, unless disabled by an option, this will close the current shell (EXIT)
Ctrl + Z Send the signal SIGTSTP to the current task, which suspends it.
To return to it later enter fg 'process name' (foreground).
Closures
Closures paradigm is amazing. It is supported mainly from functional languages.
Let’s make an example.
function first(x) {
function second(y) {
return x + y
}
return second(y)
}
So calling first(10) we will get return function(y) { return 10 + y}
in example:
add_10 = first(10)
add_10(2) returns 12
K-means find clusters
Initial set of two dimensional data and k=3. Set initial centroids randomly.
Find instances to closest centroids
Calculate new positions for centroids
Find again closest instances to centroids
Calculate again new position of centroids
Find again closest instances to centroids
In a group of 365 people it is very unlikely that everyone has a different birthdate
In a group of 365 people it is very unlikely that everyone has a different birthdate. The probability is 365!/365365 ? 1.454955 × 10?157 ? 0, i.e., incredibly small
Confusion matrix for two classes and some performance measures for classifiers
List of active ports in MacOsX
margusja@IRack:~$ sudo lsof -i -n -P | grep TCP
Advantages of XMPP
Choosing IoT protocol it is important to make right choice. I found good table that helped me from
http://claysterworld.tumblr.com/
Just click to the picture to have bigger and clear view.
Linear regression with one variable and gradient descent with python
Linear regression with one independent variable is easy. It is easy to us for humans. But how machine knows what is the best line thru points? Math helps again!
In example lets take very trivial dataset in python:
points = [ [1,1], [2,2], [3,3], [4,4], [5,5], [6,6], [7,7], [8,8], [9,9] ]
And some lines of python code
a_old = 34 # random initial value
a_new = -2 # random initial value
b_old = 34 # random initial value
b_new = 3 # random initial value
learningRate = 0.01 # step size
precision = 0.00001
while abs((a_new – a_old)-(b_new – b_old) ) > precision:
ret = stepGradient(b_new, a_new, points, learningRate)
a_old = a_new
b_new = ret[0]
b_old = b_new
a_new = ret[1]
print ret[0]
print ret[1]
print “—-“
And stepGradient code is behind gradient descent formula
def stepGradient(b_current, a_current, points, learningRate):
b_gradient = 0
a_gradient = 0
N = float(len(points))
for i in range(0, len(points)):
b_gradient += -(2/N) * (points[i][0] – ((a_current*points[i][1]) + b_current))
a_gradient += -(2/N) * points[i][1] * (points[i][0] – ((a_current * points[i][1]) + b_current))
new_b = b_current – (learningRate * b_gradient)
new_a = a_current – (learningRate * a_gradient)
return [new_b, new_a]
After running our code, at least in my computer the last two rows are:
0.0152521614476
0.997576043517
So the first one is basically 0 and the last one in 1 – pretty perfect in our case.