Adventures of a Tech, avonturen van een techneut

Theo Kleijn has his laser cutter setup and it was time to make something useful. Theo's blog :  http://pa0kn.nl/#home I took a board I had laying around, a 16 relay board, similar to one found here :  http://www.ebay.com/itm/16-Channel-12V-Relay-Module-Coupling-Optocoupler-High-Trigger-For-MCU-Arduino-/221358546298 and  http://www.miniinthebox.com/16-channel-12v-relay-module-board-w-power-lm2576-optocoupler-protection_p903439.html And decided to make a nice base for it, so it was not directly on the table. I started by designing the base plate, I measured the board and made a drawing in LibreCad, which was in the Ubuntu repository. This was not a success, when trying to save the file the program segfaulted and all my work was lost. I already had a license for QCAD 2.2 (on which LibreCad is based) and have used it without problems on my old linux machines (in 2008 and later). The old version I had was alright, many productive shortcut-keys etc, but many impr...

My sister came walking in with her small Sony Radio/Cassette/CD-player. Of course there was a problem with this device The volume control was not working, when at "0" it would mute, but at low level it would just go too loud. Luckily I found a schematic online : http://diagramas.diagramasde.com/audio/HCD-EP30%20EP40%20sm.pdf After some investigation I figured out that the LC75392 was in control of the volume http://pdf.datasheetcatalog.com/datasheet/sanyo/ds_pdf_e/LC75392.pdf I traced the problem to the main circuit board and started measuring all the voltages (given in the schematic) and they appeared to be all right. I then used my new audio-sniffer to track the audio from the radio receiver. http://www.openmusiclabs.com/projects/audio-sniffer/ This is where I got one from Santa-Claus. Some example of someone else tracking a signal with the audiosniffer here on YouTube. http://www.youtube.com/watch?v=ZxUItbtYl_0 I noticed that I was getting a l...

Het heeft even geduurd voordat ik het snapte (en nu vind ik het nog een vreemd concept) maar ik heb ondertussen bitcoins. Ik heb uitgevogeld hoe je een wallet maakt, hoe je er geld op zet en nog wat details. Het lijkt ingewikkeld maar is dat dus helemaal niet. Ik gebruik Armory (https://bitcoinarmory.com/) dat samenwerkt met bitcoin-Qt (https://bitcoin.org/en/download) Via https://bitonic.nl/ en https://bitmymoney.com heb ik wat transacties gedaan en dat werkte vlekkeloos. Wat me vooral opviel was dat je ontzettend lang moet synchroniseren voordat je aan de slag kan, heb geduld, trek hier gerust een nachtje voor uit, daarna loopt het snel. Als je geld via Ideal overmaakt naar je bitcoin adres staat het er binnen een paar minuten op. My public wallet address is :  1DynDMhxWweJr6aoSZXUzenJMkSjaWHGxo  you can send donations there. Dus als u mij geld wil sturen mag dat op adres :  1DynDMhxWweJr6aoSZXUzenJMkSjaWHGxo Bij voorbaat dank, :-)

One of my other PC's started giving trouble. Random hangs and crashes, not normal behavior. The system runs Linux-Debian-7 so it should never crash ever. After the usual updates, rebuilding the video-driver (nvidia closed source driver) it still was not fixed, and since my wife needs the PC for book-keeping I was ordered to fix the problem (or get a new PC). Replace the Cap (with a lower ESR, higher voltage and bigger capacitance I had in stock) This is becoming a common weekend activity. :-) Problem solved. Saved myself a lot of cash again not buying a new PC.

Today I got a used APC UPS RS 1000, you know those things that should keep your system up and running when the power fails. The batteries where toasted, this happens to all these devices after about a year. Since new batteries only last a year and cost about $ 65 and can only keep your system up for a very short time I decided to hack something together. I got some brand new car batteries and hooked them up, (yes I included a fuse for safety) You might ask: "Do you really need a UPS in the Netherlands?"  Answer, "no, not really" but it is fun to have and since the UPS was free I now have some long lasting power. Here are some pictures. This is just a sort of useless nerdy fun. Power! the lights come on right away. OK, maybe 16 square mm wire is too much? General setup, 2 batteries and the UPS. And another picture. I will test the performance and add data later, I will leave this stuff loading the batteries for a few days.

A few days someone gave me a TS 201 RAID NAS made by Qnap to fix. http://www.qnap.com/useng/?sn=862&c=1697&sc=1698&t=1701&n=6731 It was very bad, the power light did not come on, it just pulsed a bit. The external power supply was broken, the capacitors 16V/1000uF swollen up. 12 Volt 5 Amps standard PSU, I had a spare so that was easily fixed. Trouble was not over, the device did not work. It beeped, lights were blinking, ugly noise from disk. Connecting to NAS did not go easily, I found the IP address by using NMAP (I assumed it was using DHCP) $ nmap -sP 192.168.1.0/24 .. some known machines.. and Nmap scan report for 192.168.1.217 Host is up (0.00034s latency). Connect to the thing using a web browser did not work. type in :http://192.168.1.217/ click 'administration' That redirected to a webserver on port 6000 why? New rules in Chrome and Firefox, blocking ports including 6000. I got something like this very descriptive message : ...

I have today finally fixed the issues with my Raspberry-PI. If I have these issues everybody must be having them, USB problems! After spending the whole day measuring and tinkering it seems to work. There are some serious design-flaws with the board, to say the least. UPDATE: it is not completely fixed, after a few hundred open/close calls on a sound card (alsa on USB) the problem still happens, the USB locks up. I will not use a R-Pi again. What a piece of marketing hype it is.  One of the thing I need the R-Pi to do is run of 12 Volts, not a 5 volt USB connector. So I added a DC/DC converter (which also insulates the ground connection, which is always good when doing audio or mounting stuff in a car). It appeared to work fine but the usb-audio-card kept failing, after opening it 20 times or so. I also have a Pi-Face board connected so that complicated the situation. When it ran it ran OK, but sometimes it just did not work. I do not like these intermittent problems, s...

This week has been a hacking week. I repaired an old charger for a small fork lift, and finally fixed instability of my Raspberry-PI board. First the battery charger, an old 30 Ampere 24 Volt charger for a small fork lift. After switching it on, the lights would light up, some clicks would follow (detecting the battery and voltage), and then a low hum (transformer overloading) followed by a flash of the fuse exploding (on the circuitboard in the charger). After some investigation I found out that the rectifier bridge was bad, just one diode had failed and was completely shorted out, I have no clue why this happened at that moment, maybe just a cosmic ray or a spike somewhere, nobody can tell. The diode was a BYD57-200 (that is a press-fit 200 Volt 35 Amp version). Going through the usual catalogs online (Farnell/RS/Reichelt/Conrad) it appeared that nobody was selling these anymore. I ended up buying one at Brigatti in Eindhoven (  http://www.brigatti.nl/  ) it is a ...

Hack of today, wall wart mod for USA to Euro connector. When receiving a low cost piece of electronics often you find these US type flat pin connectors without a good way to connect to a European wall socket. (with round pins) Today I finally used one of the many power cables I have laying around, probably cut of an old CD player. I soldered the wires to the flat pins, added a tye rap, used some heat shrink. This only works when the PSU is universal (100-240 volts) I guess using just heat shrink is not official a good enough insulation :-) (do not try this at home), but it works just fine here.

We visited Franz yesterday at took a look at his operation. San even made nice video and put it here :  http://www.youtube.com/watch?v=DIaBfVBiNN8 The printer selected was the Prusa i3. I will post updates on how it works and the assembling of the machine. Update 8/9/2013 It works at last at last... Some pictures of the construction After a build that took about 30 hours of soldering, improvising and tweaking, including getting all the software set up correctly.

The Raspberry PI or R-pi from  http://www.raspberrypi.org/  is well known these days. It is not an accident that I have one, I have been doing Linux stuff since 1991, and professionally since 1996 I can not skip over these developments, have to keep up with the new kids. :-) Times have changed, hardware has become very affordable, everybody knows the Arduino , Raspberry Pi and Beagle-Bone-Black (BBB). Not everybody knows the stuff that  http://www.acmesystems.it/  aka Acme-Systems and  https://github.com/OLIMEX/OLINUXINO  aka  Olimex make, so I will endorse them here. Since I am an engineer I expect to connect switches and relays to the boards and some documentation with products, not so with the " PiFace Digital " board, it comes without serious documentation, not a even the schematic. All links on their blog point nowhere. People asked them many times, yet nowhere is the schematic to be found. I finally found some info after hours of googl...

Yesterday was the hottest day of the year 2013 to date. Temperatures reached 36 degrees C. Normal value for this time of year is about 24 degrees (according to KNMI). My wife's car, a Hyundai Getz had a broken AC unit and I decided to fix it.  The AC light lit up just like normal but the clutch to the compressor did not kick in. After spending hours googling for schematics and diagrams, reading forums I found out why. The system is protected by a clever pressure switch, (conveniently located behind the glove compartment) It disables the clutch when pressure is too high or too low. After checking all things electrical, fuses, sensors, the clutch, the fans and switches I was out of options, I could not measure the pressure in the system. I visited a local car repair shop specialized in Airco systems, Rene van de Louw, st. Oedenrodeseweg 40, and he quickly noticed that I had a leak in my condenser. How? He put some pressure on the system with nitrogen and I could hear a hissing so...