JWilly's Linux Travels

I recently did up a replacement controller PCB for a customer who was having runtime issues.  The replacement PCB and firmware exactly replaces the old 68k controller system.  It is a drop-in replacement with exactly compatible connectors, power supply, and input and output signalling. The SterileMax was a prolific autoclave, and can economically fulfill your needs. If you have this version or similar, you can use my replacement. The replacement PCB is MUCH smaller than the OEM. Replacement controller for the PC1277X1, top-side. The PCB is about 1/3 the size of the original.  It helps to not use any DIP parts. Schematic for the controller. If you're interested in this design or a slightly modified version for your sterilizer, comment below and I can hook you up. The main issue this solved was over-pressure in the chamber during a run.  The NVSRAM's battery died and it lost all the configuration data.  Once this happened the system w...

No, it isn't Lead, nor is it Peanut Butter.  It is the 'B' version of the prolific ATmega328P microcontroller which started all this maker craziness off! Top view of PB Pro Mini Description This is a minimal microcontroller board with only a voltage reg, crystal, I2C pull-ups, LEDs and the chip itself.  The goal here is to reduce costs while hosting the beefy 328PB! This is based on, and pin compatible with, the Arduino Pro Mini 5v/16MHz from  Sparkfun . Notable, not-so-minor improvements for the 'B' version: 2 UARTs 2 I2Cs (TWI) 2 SPI Qtouch 5 Timers (with OC, IC, and PWM) Everything else is about the same.  You should be aware the clock driver on the chip is a low-power version, but this board and crystal operate at 16MHz just fine at 5V.  The Arduino library I've been using for the PB has been working without a problem! Getting Started You'll need a FTDI Friend  or FTDI Cable  to program this as there is no seconda...

The Atmega328PB is the greatest thing to come to the Arduino platform since the UNO.  Who wouldn't want more 16-bit PWMs and double all 3 serial protocols? The new unofficial Arduino Mini PB Pro! To get the IDE to support it, follow this guide: https://github.com/watterott/ATmega328PB-Testing Since the JSON file is incomplete for Linux, do the manual toolchain replacement.  This was a little tricky, and there isn't much on the internet on where the toolchain resides inside the Arduino base folder.  Here's what I did to make it work. I downloaded the latest Arduino build, and I will refer to the extracted base directory as "arduino-1.6.9".  Also download the "hardware.zip" and the "Arduino Toolchain (4.9.2)" Linux x64 version from the github links. 1. Replace the toolchain The builtin toolchain resides in "arduino-1.6.9/hardware/tools/avr/".  Rename the avr folder to "avr.old".  Extract the "Arduino Toolc...

ATtiny85-20  DIP-8 Fits nicely on a breadboard. I followed this guide to get it working with the Arduino IDE:  http://highlowtech.org/?p=1695 I downloaded the 64bit Linux 1.6.5-r5 version of the IDE, extracted it to a folder in my home directory. This newer version has the extra board support!  I also put the ATtiny ide files in the sketchbook folder under "hardware".  See the guide above.  When uploading, it tries to use its built-in avrdude (failing and complaining), but since I have the latest and greatest (6.1) in my /usr/bin, I (moved and) replaced it with a simlink to my system avrdude.  Then I loaded up Blink to test on "Pin 0", and wala, we have a blinking tardis: A TARDIS working.  It's totally bigger on the inside. I can use the power from my USBmicroISP (power jumper installed) to give it 5V.  Very nice. Sometimes the programming wouldn't initiate.  I found that I had to close the IDE, unplug the USBmicroISP, then...

Actually using my USBmicroISP with microcontrollers other than Arduino Uno's led me to fix a udev rule issue with my Gentoo Linux laptop.  I was getting Permission Denied when I was trying to use avrdude as a normal user.  Yes, my user is part of the 'uucp' group... Background Some background on the Arduino ISP connector.  It is much different than the 10-pin AVR connector... 6-pin ICSP cable pinout.  NOTE: Numbers refer to ATtiny45/85 pins, not ICSP! Arduino ISP pinout. Notice the vertical line next to pin 1, which appears in silkscreen on the PCBs. Redboard ISP pinout.  Obviously the same as UNO.  Notice pin 1 location on upper-left, with horizontal white silk. My USBmicroISP has the cables coming off the IDC differently, but the key is in the correct orientation to the pinout in the top picture! (Please disregard numbering on first picture for ICSP purposes)  Usually the key and wires are facing inward (left side on 2nd and 3rd ...

Ah, that age-old old-timer, the 555 chip.  It can be run in either astable (think repeating clock signal) or monostable (single pulse, then done) mode.  I'm going to outline a simple monostable design, and some of the tricks that I needed to use to get it working great. Design of a 555 Monostable 1 to 10 second Timer Monostable timer with 24V trigger Two Component Timing This particular design I needed to turn on a relay for about 5 seconds when the 24V rail came on.  The basic timing of the 555 depends on R1+R6 and C1, in my circuit.  The equation is as follows: τ = 1.1 R C This is also displayed on the datasheet on page 10 as a graph of common resistor values. I chose 4.7uF and 1MΩ, which equates to τ = 5.17. I wanted my timing adjustable by at least 1 order of magnitude, centered on my 5 seconds.  Thus, a minimum R of 200KΩ and a maximum of 2MΩ.  I went with a split series resistance: a fixed 100KΩ and a 25-turn 5MΩ potentiometer. ...

Intro Continuing to document my USBmicroISP, based off the  USBtinyISP  from Adafruit, here is my the assembly process. My first post  detailed the why  I'm building this version, and its features.  Essentially I wanted to make it with a smaller, nicer looking enclosure and have it use a micro USB cable, not a printer USB cable.  I used much the same schematic. Assembled USBmicroISP; green means ready for programming! Parts Received I often buy the parts  FIRST, then check that I designed the board correctly by printing it out 1:1. Lining up the new, often-weird parts (the ATTiny, the XTAL, the MicroMatch connectors) made me realize I needed to rearrange the way the connectors go out of the case: Finished product.  Tight quarters in this case! Having finally received the PCBs reminds me again how amazing OSHPark is: Nicely fabricated OSHPark boards.  Notice the ATTiny IC1 is on the top layer, and the buffer IC2 is on...

Intro I thought I'd share some useful scripts for systemd that replace a cron daemon, and that I use on many of my Gentoo machines.  Since moving away from openrc, I had to relearn a bit, especially the daily cron jobs that I was so used to.  But I will trade crontab -e for journalctl functionality any day-- so useful.  Anyways, I no longer have any crons installed.  What to do?  I have 1 Gentoo headless file server that needs to run all of these services, 1 desktop (the "bulldozer") and a couple laptops that need to run a subset of these services. 1. Eix-sync Service and Timer I have the excellent eix  program installed, and use the wrapper eix-sync for portage and overlay syncing and eix database updating in one shot.  Naturally, I want to run this daily for all my machines, and I have my server as a local portage mirror (just a matter of changing the make.conf SYNC setting on the clients: SYNC="rsync://jwilly/gentoo-portage").  Th...

Squashmount and aufs: Gentoo on tiny 4GB root! I came across a post about "squashing" certain directories on a Gentoo install (portage tree, portage db, /usr/src/, etc) much like those minimal-install-cd's use!  AuFS is an improved "union" filesystem.  I don't understand it all, but as a hardware engineer it's kinda like having a dual-port memory (I think).  Given that many of the directories I want to squash also contain many, many tiny files, mashing them all together increases performance on disk reads (supposedly). My Eee PC 901 still functioning... I was intrigued as my little netbook has its SDcard slot occupied for quite some time with a 32GB card for the /usr directory (2GB swap space as well!).  I wanted to change that.  I wanted to see if I could actually use my netbook as an " ultra-portable internet-connected enduring-battery system..." and happen to run a really snappy source distro!   The technique requires a very...

The goal here is to setup Gentoo Linux on an SDcard for my Raspberry Pi model B without display or USB keyboard.  Yep, I didn't have a HDMI cable and my USB keyboard died a long time ago... I followed this Quick Install Guide mostly.  I'll outline what I had to do different than the guide. I've been meaning to set up my distribution of choice on a RPi, and my work needs a little server upgrade to host some files securely.  Yes!  Now I finally have a good enough reason. Raspberry Pi model B with only power and LAN. Following the Guide Steps 1 through 3 can be done normally on a Linux system, as this is just prepping the SDcard. Parts of Step 4 need to be done before booting, so you can ssh in.  I couldn't chroot into the sdcard like I'm used to in a Gentoo linux install.  Kept getting /bin/bash Exec errors.  (I think it has to do with the different archs (armv6 vs x86) and the incampatible binaries?) Setting the root password manually ...

Sometimes you have to leave the house, and where I live there tends to be a inconsistent amount of snow. Well, I purchased an old Sears Eager-1 5HP 22 inch snowblower (model 536.909400) from a good friend of mine last year, and never got to use it . Needless to say, it was a bit hard to manage the snow this year, as it's got bad tires (no chains either) and a bad muffler (ouch).  It's got plenty of power, but it doesn't push so well.  Here's why: Trying to replace these terribly round things proved difficult.  Not available from Sears Parts Direct.  Ebay it is.  Eventually, after much searching, came across these beasts: 11 x 4.00 - 4 Wheel, 2 Ply Tractor Tread, 3/4" ID w/ 2 Crossholes x 3-1/8" Symm They might look a too big, but the originals (with no tread) are 9.5" dia, and these are 11".  I don't care.  The width is just about right, bore is 3/4", and they've actually got tread!  I won't have to utilize ramming...

USBmicroISP v1.0:  The Beginning Steps of Dev I like small things.  I don't know why.  It's something about slimness, minimal living I guess.  I drive a Honda Civic, yes. To develop for a micro-scale, wearable electronics project, you have got to have a smaller  USBtinyISP  programmer.  Take the guts of that ISP (in-circuit serial programmer) project (props to the original devs there) and put them in this amazingly small box? Don't you just want to put something in there? Just imagine if small things weren't a thing. You'd be wearing THIS: Do not try to wear this at home, kids. Oh, the HORROR. Anyways... Here's my re-design that is mostly based off Adafruit's USBtinyISP and USB tiny code & design .  I just wanted to...ah... improve it a bit.   The Design Smaller, uses micro USB instead of large printer one, and looks cool, too.  The design is mostly reduced to SMD components, which presents the prog...

Restart Into Electronics (and not getting lost) So I decided to really start investing my wandering hobbitual energies into something that I had heard about back in 2009 or so while in college (see my project  Let's Make Things Talk blog ).  What I speak of is the Arduino project.  Well, let's just say the Arduino world  ever since the opensource community embraced this wholeheartedly.  So cool to see that happen.  Personally, I've also wanted to have something worthy to communicate to the world. Xmas gift from my brother, to add to the tool collection!  Ask and you shall receive. The Restart for Myself I have many interests, too many probably.  Too many hobbies, things, inventions I like to dream about.  They seem to all revolve around making and creating (the will to power).  You know that feeling of squelched passion ?  I've found release in channeling that into my original love: electronics .  Hardware and s...

I discovered an AMD Geode processor lurking in a slim client SBC (single board computer) originally for a printer kiosk.  I wonder if I could fit a TinyGentoo  onto its 128MB compact flash card??? Introduction and overview I will utilize crossdev, and avoid any chrooting problems and mismatching CHOST/CFLAGS... Customize the target systems make.conf generated by crossdev. Compile and install packages into runtime tree. [picture of slim client and screen] >>>I'm writing this while my Gentoo system cross-compiles a i486-pc-linux-uclibc toolchain into /usr/i486-pc-linux-uclibc. There are many resources that I had to pull together to get this working: http://en.gentoo-wiki.com/wiki/Tiny_Gentoo  HOWTO guide to install a 5MB system on a USB flashdrive or similar http://www.gentoo.org/proj/en/base/embedded/handbook/index.xml?full=1  Gentoo Embedded Handbook details cross-compiling for various dev boards http://judepereira.com/blog/going-...