Adventures of a Tech, avonturen van een techneut

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, so I

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 30 minute

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 google-work, someone made a c

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

I have done many things already, but recently someone asked me to find a way to automatically test and report findings on very large Diesel generators. The project involves building a portable (with a crane) setup for testing the performance of generators upto a power of about one MegaWatt. (MW) For me that is a lot of power.  The test involves increasing the power output stepwise and measuring the response of a generator, including Current, Voltage, Frequency, Power factor and Temperature.  I have taken a picture of the resistor array we apply to consume this much power from the generator. The resistor array has forced air through it, and can take about 3 x 1500 Amps at 400 Volts. The plan for now : Laptop with RS485/Modbus to the control- and measurement- equipment. Possibly linux as the OS to prevent tinkering, security, driver and update issues. update 2013/6/13 : I already wrote python program to control the measurement module ( Diris A10 over modbus RS485) updat

Program to control Relay-Board via USB on BitBucket https://bitbucket.org/oetelaar/ch341a-relay-board I wrote a new small clean program to control this board from Linux. No need for any 'drivers' and other stuff, just type 'make' and it works.