relay circuits are "hello word" projects of electronic prototyping. Long time ago, when got my first computer i created one of them and controlled the desktop peripherals via pc software. this kind of desktop automation can really save your life if you have ADHD or something. first prototype was driven via parallel port and a visual basic application was controlling directly the motherboard resources w/o any kernel driver or something.
at the beginning, i realized the this kind of setup causing the electromagnetic interference due to mechanical relays. and eventually causing BSOD. someday i decided to create another relay box from scratch by using PIC16F877 so relay box will be declare the it's independence, as the result we won't need to worry about bsod's. i was controlling it via comport and bundled another PIC controller to reset the circuit in spesific time period. with this setup device can continue to work even if microcontroller frozen or stuck which caused by EMI
Second attempt was in 2009, i met with the arduino in this year and created same relay box by using uno board and one relay module which purchased from ebay. i was hoping this kind of "ready to use" components will be completely robust and stable instead of my handmade boards.
But it's not!
I still messed with EMI problems and headed to another rubbish idea. this time, provided power to +12v relays by using set of +5v small relays which connected to arduino. and one of them was bridged with a bigger relay called contactor which designed to handle heavy electical loads. as the result, i was solved the emi problem by using three level of isolated circuits but wasted 9 relays just for 3 power outlet.
Here's the starting point of this entry. the second version (black box on the picture) still working without any problem but it's getting obsolete. making too much noise, drawing unnecessary power etc.
few weeks ago researched the solid state relay modules and decided to create a final version which will lasts about another 10 year. ssr relays are working like mosfets so they're completely emi-free. i purchased a relay module and another arduino board and just connected them together within one hour. then i found the enough time to focus the box design and it's firmware.
as the result, final version costs me about $35~40 plus two weeks. now it's completely silent, stable and powered directly from usb which cannot draw more than +5v ~ 500 milliamps.
another software controlling that box to turn on desktop peripherals upon pc boot and turning off them when user away from computer to save energy. actually that's not a big deal but this kind of small details really increasing the life quality and returns as motivation which required for development of more bigger things.
If interested, it's source code available in devzone section.
I'm using vaio vgn-p13gh since 4 years. as a windows guy, it's very useful for me while working on field. Problem is it's getting obsolete (even sony no more manufacturing electronics today) you need to be fast when you're on mobile.
most netbooks uses 1.8 inch hdd including this one. i decided to replace it with a ssd but seems it's not so easy as i thought.
Choosing the parts
It's hard to find 1.8 ssd in market. also it will not be cheap even if i found it. Compact flash cards are fast enough as a ssd. they're widely using in professional photography. kingston 266x was my decision due to it's speed and price.
we need a 1.8 zif adapter for that, i found my cure at the dealextreme when i received the package at two months later, even i was forgot that purchase. poor me.
Here is the tricky part, cf cards are usually appear as portable/removable drive in operating systems. and windows7 refuses install itself to a removable drive.
There are a lot of firmware tools on web which can convert cf cards to fixed drives. instead of that, i tried to forcibly install win7 via an alternative way and succeeded with that. a guy created an alternative installer for windows which can directly extract the .wim packages to target drive. he's not included the depencies in zip archive but complete toolset is available in here.
after the spending $25 plus three hours, got 3x more faster disk access and the annoying mechanical disk sounds are gone. due to nature of cf cards, writing speeds are low but that's acceptable.
Since i last mentioned about oculus rift at past year, hundreds of commercial & non-commercial oculus clone appeared on web. all big companies rushed into market but there is no any stable consumer product exists yet.
After I tried a friend's Oculus DK1, decided to purchase it when available. my expectation was a consumer product within next few months or low price used units in ebay at least. because higher price tags doubles the cost due to customs regulations. (xx percent fee)
Anyway, waited a while and decided to build my own kit. Purchased the components at recent summer based on the Rod Furlan's instructions and builded it within 3 weeks including two failed attempts. and i finally catch the original rift experience.
Current unit completely built with same components of DK1, except head tracking thing. i'm not going to play half-life in 540x480 resolution instead of 23" 1080p monitor. so it's not necessary. instead of accelerometer, i installed a magnetometer to it. it's more easy to read single polar bearing rather than complex accelerometer calculations. body kit built with acrylic glass material (the accident, remember?) and bunch of silicon glue. surprisingly it's still under 500gr and tough as hell. i accidentaly dropped it multiple times and not even scratch exists (yet) also integrated a playstation eye webcam for future use, will mention about that in next entries.
Result is $160 cost and 3 weeks of development, enough to watch 3D movies and run tech demos for now. currently still working with software part on my spare times. more updates will be available soon.
previously mentioned about an arduino sketch which can gather data from various sensors and push them to my home automation & personal assistant software called "Judith"
Today i implemented one LDR and BMP180 barometric pressure sensor. LDR's are really old technology, even was exists inside of automatic night lamps at my childhood. i suppose they're just reacting too dark or lighter environment but surprisingly i found this one very sensitive. it can detect light changes step by step while sun goes down at the evenings. currently judith controlling hallway and my rooms light switch based on her own day & night calculations. i will use this data as correction value for cloudly days which light will be needed at a rainy day.
Bosch's bmp180 barometer unit is really small even exists in motorola xoom tablet. you can calculate approx. altitude from pressure value but i can't get the point why a tablet bundled with a barometer. probably a marketing trick to make it more expensive. By the way, it can also measure temperature but when compared to ds1820b and DHT11 it's value 3 celsius lower than others. probably surrounding metal case causes that. also pressure resolution not too high as described in other diy sites. anyway can be used in weather alert applications at least.
it's arduino compatible library available in here
Few weeks ago i decided to upgrade my pc's ram modules, this upgrade was also requires bios update due to a bug of mainboard's (foxconn G41MXE) firmware. anyway downloaded the latest bios, replaced the hardware and spent few more minutes then changed the manufacturer's ugly oem logo. my plan was extraction of image file from bios dump and replace it with another picture which is fits byte to byte.
before that, surprisingly found a tool which can already do this process automatically within few minutes. if interested it's available in here: AMISuite.zip
i'm not sure its torrent alive now but at past year (2013) ami bios source code was leaked online from a taiwan based manufacturer's ftp server. also it's available in here. the code is completely ready to compile and well-documented. a great research material for students & modders. you cannot launch your own computer brand like tv show halt and catch fire but free to try non-commercial experiments with it.
once upon a time, google was have a desktop search solution for win32 based systems. i can't remember maybe at 2007~2008. it was allows you index and search your local files as google search interface.
after the new index feature of windows vista, they're abandoned the project but windows indexer doesn't have not all features of their engine. for example year is 2014, microsoft released windows 8.1 and still have no portable drive support. if you eject drive and jack into another usb port, all metadata is become obsolete. also index process 7/24 working in background even playing games, watching 4K videos etc. that's causes performance drops in system.
Whatever, two months ago i have a lot of spare time and decided to rebuilt their web based local indexer from scratch. it's easy in theory but requires a lot of legwork. then decided to create it as php script. that will allow us faster development, quick upgrades and more flexibility.
- First of all, implemented an embedded webserver into judith. she's already accepting web api calls for mail & skype notifications, just added few lines extra code.
- then started to create a lite version of "C.A.I.N" it's a codeigniter based web application engine which i'm using it in almost all commercial projects.
Indexer project has two controller: one of them building a disk structure and writing them into a portable sqlite database, other controller is showing the search results visually.
- Third step is a custom browser, that's necessary to launch huge inputboxes and show results in a multi-monitor setup. used chromium as web render engine. i already did few experiments with it before, that was the easy part.
and rest of maintenance and indexer scripts automatically launching after 5min of idle, adding new files to database and removing the entries of deleted files. Currently this setup is still a prototype, i will share the project sources after it's become stable.
past year i was working with a material named methyl methacrylate (aka acrylic glass) its strong, transparent and easy to bend. best component to create cases for electronic prototypes. while working, burned a piece from that, applied glue and burned again with solder iron to clean up splinters. probably that's caused a chemical reaction and exthausted a harmful gas. i aware that after 20 seconds but its too late for my lungs.
it wasn't a serious damage but i stayed in hospital for one night. after that accident i researched about an air analyzer gadget like r.r.t.s equipment in doom movie. finally discovered MQ gas sensors which manufactured by an east-land company named HANWEI.
purchased MQ5 and MQ9 for testing purposes and found incredibly sensitive which can be used at industrial level. MQ9 sensitive for waste gases like CO/CO2 and MQ5 can detect combustible gases such as propane/butane.
mentioned on previous entries, i already have a talking (in turkish ofcourse ) digital assistant named judith. she's serving me since 5 years and can provide visual & audible notifications based on internal variables. eg. battery level drops below 50 percent or memory usage higher than 90 percent etc. today i developed another application to gather data from arduino and send to her.
first, tested it with a deodorant which is seen in video. after 36~48 hrs of work, both of sensors become very sensitive even detects human fart (including silent ones ) also product datasheet verifies that by calling it as "internal burn-in time" two week later i discovered a fact, usual raw value of mq9 sensor is around 200~250 but its dropping to 150 at each morning and weekends. streets are empty in these hours, my opinion diesel car exthaust causes carbon contamination in district and it detects them. if this kind of a gadget exists on market, peoples can barely see side effects of liquid fuels.
we're fucking up the planet earth, this is the another fact.
2012 was SDR year. some guys (Antti Palosaari and Eric Fry first) discovered possibility of using realtek RTL2832 based devices as generic radio.usually that chips can be found in usb dvb-t sticks which can bought with 10$ from most markets. In same year, i read an article on hackaday and decided to purchase one of them. and did almost all available stunts from positioning ships & airplanes to gathering weather data from satellites in past two years.
i was seen strange signals while playing with it, now compiled all of them in this article. my setup is 1x Terratec Cinergy T Stick, 1x indoor tv antenna with built-in amplifier and 1.6ghz netbook which is seen in picture. all signals recorded in same session at 14.06.2014
Signal #1: 415.6mhz
Its looking like aprs stream, also frequency fits but no any decoders can handle that in my software arsenal.
Signal #2: 448.5mhz
that one is very similar to tty teletype, probably customized and encrypted for military purposes. also local police and fire department still uses old analog walkie-talkie systems in here, conversation stream can be seen in 450~455mhz.
Signal #3: 150.3mhz
I have no idea about that, usually amateur satellites uses that frequency range but my setup cannot catch that signal in this level. it's a mystery.
Signal #4: 152.6mhz
another signal in same frequency range, its like a telemetry data and most interesting one ever seen. due to signal level, probably its coming from a meteorology station where is 6km away from here.
edit on 30.06.2014: it was a network beacon of new model DMR radio. next week i monitored same channel about 48hrs and got a digital voice stream. decoded it via dsd+ and just hear conversation from new hospital of city. looks like new goverment building uses new tech.
Signal #5: 135~137mhz
yes, most strange part is in here. i was seen that few times but i supposed its a device glitch or software error. then someday tried with different antennas & different angles and i seen signal level was changed. it's obvious to coming from far away and it's not human made. i seen some guy's article which is mentioning about detecting galactic rotation with software defined radio. he was demonstrating similar signal shapes in screenshots. my best guess is that's a frequency reflection from moon or other planet's surface. we're living in a huge signal ocean, that's possible.
playing with sdr is fun but it uses too much system resources, my opinion it cannot be used in business or other proffessional purposes. if interested, you can proceed following links to dive into ham-radio world:
home of the first apps developed for RTL2832
a blog about all about things which you can do with RTL2832
all available articles about 2832 on hackaday
win32 sdr application which has native RTL2832 support