Technology at a glance!

Installation guide

Rigol DS1102E firmware version 2.01 SP1

Benjamin Sølberg Electronics

Trio Dual-Trace Synchroscope CS-1554.

For more than 15 years I have been the happy owner of a 20 MHz Trio Dual-Trace Synchroscope model CS-1554 anno 1972. A complete noob can use it, and i have been pleased with it. It didn’t cost that much (used+old=cheap) and have saved me many timed and served me well. It’s not that it is broke or anything but I wanted a new one with capture.

Note to self: Never ever buy a bitscope again

First I bought a BitScope and a MSIWind. This was NOT a success in any way, not even close, but that’s another story and WAY “off topic”.

Rigol DS1102E 2 Ch, 1 GSa/s, 100 MHz

But today is a fine day. My Rigol DS1102E 100 MHz oscilloscopes has arrived and has been in use for the first time.
Both the build quality and packing alone shows that this is not your ordinary Hong Kong product. This is a professional product to a fraction of the price. So how much is it, you may ask. Only $799 here

I must say that I am very pleased with it.

EDIT: It didn’t take long to get used to, I now use it is as easy as my old one and I am SO pleased with the long mem capture function!

Benjamin Sølberg Electronics

I might just be that I have a build in sound intolerance. But hearing bip-bip-biiiiip when ever my multimeter shifts between ranges in auto range mode has annoyed me for years.

So yesterday I finally made it a priority.

The easy solution would have been to remove the piezo element (that’s the black thing you normally would call a speaker). But then i would sacrifices the audio feedback on the continuity tester.

Instead I placed a sticker over the sound escape, without much success.

Neither two nor three pieces did the trick….

Last solution was to insert a resistor in series with the positive wire from the instrument to the piezo element. (I can’t really any reason why I couldn’t have used the negative instead)

I ended up using a 39K ohm resistor but only after I had been doing a lot of hardcore math.
[To be honest, I didn't calculate anything; it was pure trail and error]

Sound damping

Anyway, I now enjoy using the multimeter much more.

Did I mention that I have a toaster that has a build in piezo with a REALLY annoying sound, especially early in the morning!

Benjamin Sølberg Electronics

I have once before written about how to convert a Erisson data cable into a generic JTAG cable.
Only problem was that it needed 5V and the hardware I use only supplys 3.3V.

Nokia DLR-3 JTAG

So when I found an old Nokia DLR-3 data cable i immediatly turned to my frind Google. What I found was that it used 3.3V which was perfect. The Erisson data cable got its supply from the power adapter (5V) while the nokia flavor got it from the mobile phone.

I found some homemade schematics for a DLR-3 look alike which indicated that it should be possible to use the TX and RX pins alone. I fired up the soldering iron and as the optimist I am, I started to solder female test leads, which i scavenged from the 5V Ericsson converted counterpart.

Half an hour later (thats a lie, nothing only takes half an hour) I was done and ready to test it.

I opened my (working) FON router and after swapping RX and TX test leads everything worked perfect.

The nice part of the DLR-3 is that it gets its supplie from the two other testleads as well, meaning that I didn’t have to use an external powersource as I had to with the Erisson version.

The layout of the Nokia pins I used is : 1(3.3v), 7(RX), 8 (TX), 9 (GND)

Links:

http://www.nokia-tuning.net/index.php?s=cabledlr3 points to a DLR-3 schematics

http://wiki.openwrt.org/OpenWrtDocs/Hardware/Fon/Fonera points to the FON JTAG pinout

http://www.pinout.net/browse.php?conid=66 points to a (now old) Nokia pinout connector.

Please note that the the supply voltage is 3.3V. Luckey for me, thats what is available in the FON router.

Benjamin Sølberg Electronics, FON

While searching for informtion on statemachines to be used in my “Safe 12vdc to 220vac inverter control box” i sumbled upon an extremely lightweight stackless threads library called ProtoThreads. Although I don’t think I can’t use it because of the stack limitation on the PIC12F508/9 or PIC16F84 that i plan to use, it is worth mentioning.

Here is an abstract of descripton found on the webpage:

Protothreads are extremely lightweight stackless threads designed for severely memory constrained systems, such as small embedded systems or wireless sensor network nodes. Protothreads provide linear code execution for event-driven systems implemented in C. Protothreads can be used with or without an underlying operating system to provide blocking event-handlers. Protothreads provide sequential flow of control without complex state machines or full multi-threading.

A simple task is defined like this:

#include "pt.h"

struct pt pt;
struct timer timer;

PT_THREAD(example(struct pt *pt))
{
  PT_BEGIN(pt);
  while(1) {
    if(initiate_io()) {
      timer_start(&timer);
      PT_WAIT_UNTIL(pt, io_completed() || timer_expired(&timer));
      read_data();
    }
  }
  PT_END(pt);
}

Benjamin Sølberg Electronics, Links

Here is a good link on how to do it, including background information..

http://web2.murraystate.edu/andy.batts/ps/POWERSUPPLY.HTM

Benjamin Sølberg Electronics, Links

Hvis du skal beregne hvor tyk en leding skal være for at kunne trække en bestemt spænding og strøm, så er der her et link til hvordan man gør samt lidt flere informationer:

http://www.praestkjaer.dk/dk/emner/elektricitet/el-kabel.htm

http://home1.inet.tele.dk/ehh/elektronik/formel/spm/spm.htm

Ohm’s lov

http://home1.inet.tele.dk/ehh/elektronik/formel/ohm/ohmslov.htm

Mit specifikke behov var 12V, 50A = 600W over en afstand på 3 meter.

Så 16mm²  burde være nok, men jeg gik op på 21mm² (da det var hvad jeg kunne skaffe) for at være sikker.

Beregning 0,0175 (kobber modstand pr mm2 pr meter) * 6 (2×3m, frem og tilbage) / 21mm² = 0,005 ohm

50A * 50A * 0,005 ohm = 12,5W tab på ledningerne, altså effekt som bliver afsat i ledningerne alene.

12,5W / 50A = 0,25V spændings tab over ledningerne

Keywords: mm2 ohm modstand Ampere Watt Volt ledningstykkelse kvadrat DC

Benjamin Sølberg Electronics