Archive for April, 2012

Counterfeit Electronics

After reading about counterfeit electronics in Military weapons, I never though that I would find any counterfeit products in any of the many devices I take apart. The other week however, this thought was disproved!

The school I attend won a Promethean ActiVote system which consists of 30 modules to vote on multiple choice answers with and a base station to connect all the modules to the computer via USB. The USB cable had been trapped in the box causing it to fracture due to the appalling quality of the cable. You can see from the photo to the right, the white ActiVote USB cable has no foil inside to shield the conductors, nor does it have the stress-releasing string that should stop fractures like this.

 

Anyway, opening up the unit I found a small 2layer PCB which contains an MCU, USB controller chip, wireless chip and some memory. One thing that struck me as odd was the strange black marks on (what was later found out to be) the MCU. The code on it has been scrubbed off, and a new one inked over the top of it! There was also a marking reading “PRS 10” engraved in a very dodgy manner. A little rubbing alcohol and scraping later, I managed to reveal a chip code that was slightly different to the one inked on top. You can see the markings in the picture below.

 

After some careful lighting and googling, we found the chip to be a Renesas H8S/2134 with a retail price of about $15. This obviously makes it worth counterfeiting with this high RRP. I cannot see that the chip is an old silicon revision and the module seems to work once I had soldered on a new cable.

The counterfeit electronics business is obviously massive and according to this slightly dated NASA report, the quality of the fakes varies massively. The quality of this fake was fairly bad with the new code inked on with water-soluble ink, but at least the chip is functional!

Friday, April 27th, 2012 Take-aparts No Comments

Major Update: Digital Oscilloscope

The Alpha revision board It has now been nearly 2 years since the start of the USB Digital Oscilloscope project and it is still going strong!

You can see in the picture the alpha revision oscilloscope that has now been superseded. It was designed in Eagle and consists of a 2layer PCB with a Xilinx Spartan 3AN FPGA, DDR SDRAM, Maxim ADC and Cypress FX2LP.

We went for a modular design in the end with separate input boards and USB board. This makes the system easier to debug by isolating different systems and makes it cheaper if any components need to be redesigned. We were very luck that there were very few mistakes in the PCBs so we only had to make one or two fixes.

Due to hardware restrictions (mainly the FPGA not being able to contain all the code) this design has now been retired and a new version is in the design process. The updated version now has a Spartan 6 FPGA at the centre, DDR3 memory, a 1GSPS ADC and Cypress FX3 which will provide SuperSpeed USB3 communications.

After deciding that the project could no longer be implemented on a 2layer PCB and the Eagle Free version only supports 2 layers, we had to look for other software. After doing some work experience with an electronics company, I was lucky enough to have a play with Cadence Allegro. I found that Altium Designer (a very similar product) seem to support a few student projects so I thought it was worth a try emailing them. Several weeks later I managed to score a year-long Altium Designer licence with an Altium Subscription free of charge! The acquisition of this software has meant the design process is a lot faster and easier, but understandably we cannot use the licence for commercial use.

I will post again soon (he says after not posting for 2 years!) with more HW&SW details and hopefully all the schematics.

Wednesday, April 25th, 2012 Electronics Projects No Comments