Building the OpenTheremin V3


I received a bare board and some of the SMD components for a OpenThereminV3, it is a semi-assembled kit that can be bought from Gaudi ( ). The board I got was from a previous unsoldered kit where you have to buy all the components yourself. This totalled to another 35€ in parts as I do not have much SMD components in stock.

It is made as a shield that mounts directly on a Arduino Uno, which also makes the programmering very easy. Plug in USB, download source code from github, download the source to the controller and start playing on your new theremin!

The whole building process is very easy from just looking at the parts list and the schematic when you are in doubt, the silk screen layout is almost good enough to just use that along with parts list to solder it up correctly.



November 26, 2017

I made a video of the soldering and building process with a bit of testing it at the end 🙂

Here is some more detailed photos of the enclosure, antennas and boards inside. Starting with the Open Theremin V3 board where it is all soldered up and I am fairly satisfied with the result as I just used my regular soldering iron used for DIP components and a very thin solder.

The Arduino Uno board mounts directly on top of it and fits nicely inside of the enclosure.

I used 4 different colour knobs for the potentiometers so it was easier to remember which is volume, pitch, register and timbre, as I did not have anything in mind to use as a front with texts on.

The antennas is all done by hand and bend around a wine bottle, easily done and the result is absolutely perfect!

I did a quick test setup where it was just connected to a tube amplifier I have in my lab, in the future I will try to modify it for MIDI output which there is a separate guide on ( )

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Happy New Year 2018 slow motion special!

Happy new year to all the readers, followers, subscribers, liker’s and users that has to do with reading, commenting and writing on or

I have filmed a small new year special video for you all! See you all in 2018 for more high voltage exploration and experimentation!

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Teardown of a medium voltage fuse (7200 V / 200 A)

I got my hands of a old NEBB (Norsk Elektriske Brown Boveri) medium voltage fuse, rated for 7200 V, 200 A and 350 MVA. My best guess from the company name is that it originates from before 1988 where NEBB was merged with ASEA into ABB.

Medium voltage fuses are used at the secondary side of distribution transformers, which are often the link from the transmission grid to the distribution grid.

Here is the video of the teardown and below are some of the pictures, which also are used in the video.

The fuse implements a Striker system that is a series of trigger mechanisms to let a spring loaded pin fly out of one end, in case of a fuse failure, to activate a mechanical shutdown or electrical feedback when there is a blown fuse due to over-voltage, over-current or too high temperature.

Here the disassembled fuse can be seen, the blown fuse element and the single small parts of the chain that has blown apart nice and evenly. Typically a single wire in a fuse will cause a over-voltage surge. To resolve the over-voltage problem, it has been necessary to divide fuse elements into sections, thereby causing them to blow gradually. In technical terms, this is achieved by punching notches into a smooth strip. The fuse element is made from pure silver (999)

Silver is the preferred material for these fuse elements. For a number of reasons relating to physical chemistry, silver ensures the cleanest break. Its low resistance, due to its relative chemical stability, makes it the ideal material for carrying an increased current without the risk of aging (operating temperature of a strip: 180 to 250 °C).

This is usually sand (quartzite), which, by vitrifying, absorbs the high levels of energy developed by the arc and combines with the silver to form an insulating compound known as fulgurite.

The purity of the sand is essential to ensure reliable breaking in all areas, as is the absence of metallic compounds and humidity. Furthermore, its initial bulk ensures that the pressure (and therefore the voltage) of the arc channel is maintained.

Its granularity is selected according to the following data, which has been drawn from

  • too fine a granularity (< 20 µ) is very
    detrimental as its high density, which slows down
    the diffusion of the fuse metal between the
    grains of sand, makes the gradual elongation
    and subsequent extinction of the arc difficult
  • fine granularity facilitates breaks early in the fault current but also favours over-voltages
  • coarse granularity facilitates breaks late in the fault current.

Modifying the granularity also enables the time/current characteristic in the zone 10 ms, 500 ms to be made more concave.

The still intact fulgurites from the melted fuse element can be seen here in greater detail. It is really interesting to see how the inside is now a insulated glass tunnel and the small silver beads have been pressed out and fused with the sand. The structure of the fuse element creates fulgurites that has alternating white stripes containing silver beads and yellow stribes that is only sand/glass.


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Taking a look at the Toshiba Toughbook CF-18 vintage computer

Here is a laptop, used for field engineering work back from 2006 where it was released. I am doing a quick overview and demonstration of this laptop. A glimpse of computer history to have a record of things, as this was decommissioned.


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5kJ capacitor bank fired at 12kVDC / 3.5kJ charge

Third experiment with the bank of 35 electrolytic capacitors connected in series. Results are better than theoretical estimate, which was 6000 A limited by ESR, so getting just over 7000 A is good, but the result is still a little tame when it comes to action. These tests had the bank charged at at 12000 VDC which corresponds to 3.5 kJ stored energy..

All discussion about this bank can be found on the forum:;topicseen#new

The first test video can be seen at:

The second test video can be seen at:

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Teardown of a IBM Blade server HS22V

Here I am doing a teardown on a IBM HS22V blade server dated back to 2010.

The IBM BladeCenter HS22V blade server supports up to two multi-core Intel Xeon microprocessors and has eighteen memory-module slots, two SSD storage-drives bays, one Horizontal-compact-form-factor (CFFh) expansion card connector, one Vertical-combination-I/O (CIOv) connector, and one internal USB connector.


  • Supports up to two multi-core Intel Xeon E/X 55/5600 series microprocessors


  • 18 dual inline memory module (DIMM) connectors
  • Type: Very Low Profile (VLP) double-data rate (DDR3) DRAM. Supports 1 GB, 2 GB, 4 GB, 8 GB, and 16 GB DIMMs with up to 288 GB of total memory on the system board
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Ericsson Radio Base Station RBS3206 teardown

The RBS3206 macro is an indoor Radio Base Station with one to four carriers and one to  six sectors at 20/40 Watt RF output power per carrier.

All the boards that I have comes from the middle row in the above picture and unfortunately I did not have any of the diplexers at the top or the power supplies that are at the bottom row.

The following 24 minute video shows the teardown step by step with explanations, high resolution pictures of the boards is in the last part of the video and also further down this post.

In 1999 Ericsson had 17 test systems running around the world with WCDMA, which is better known as 3G among normal people. WCDMA stands for Wideband code-division multiple access. This RBS3206 indoor macro system is from around 2008. It also supports all these technologies GSM / EDGE, WCDMA / HSPA and LTE.

The RBS application software is distributed over several processors using the interprocessor communication offered by the platform. The main processors of the
RBS 3000 cooperate to form a main processor cluster (MPC) that executes most of the
control software. The processors that make up the MPC are equal in terms of control —
that is, there are no master-slave relationships between them. However, if one of the processors fails, the program execution is moved to another main processor in the
MPC. For control, most boards are equipped with a board processor (BP). Those units
that do not contain a board processor are monitored by other units.

The circuit analysis was made rather difficult from all the custom marked Ericsson parts and other ICs where it is not possible to locate a datasheet.

The main CPU is a Ericsson “AUC” with part number ROP 101 1190/2 which has 128MB ISSI42S32400B SDRAM and application is stored in Intel Numonyx 128MB flash memory.

The Altera HardCopy II is a 350 MHz ASIC with 8847360 RAM bits that handles the translation of the telecom data protocol to a single bit data stream that is sent to the digital to analog converters in the transmit part of the board.

The Ericsson “WARP 1” ASIC labelled ROP 101 089/1 R1A is the encoding IC that takes the single digital data stream from the analog to digital converter and encodes it back into the telecom protocol to go back on the wired network.

The two connectors, that can barely be seen in the top of the picture, is the connections to the receiving part of the diplexer module.

The signal first passes through the 3rd order ceramic resonator bandpass filters and goes to the first Maxim MAX9993E down conversion mixers that brings the 1950 MHz signal down to a frequency between 40 to 350 MHz, by the use of the Analog Devices ADF4106 6 GHz local oscillators for the intermediate frequency.

A TriQuint SAWTEK 856496 208 MHz SAW filter, which is a sonic acoustic filter, insures a high efficiency isolation between first and second down conversion mixer setup.

The second Infineon 60744E, which is a unknown IC, down conversion mixer brings the signal even further down in carrier frequency by the use of the Analog Devices ADF4116 550 MHz local oscillator for the intermediate frequency.

At last the analog signals are converted into two channels of fast single digit data lines by the Analog Devices AD80137 which is a ADC with unknown specifications.

The input to the 3G / WCDMA part of the receiving circuitry goes directly to the circulator at the power amplifier board. I am not sure how this work, if it is just for internal measurements of the amplified signal or if it is a part of the cell network.

The signal goes through the Maxim MAX9996 down conversion mixer which changes the signal to a lower frequency with the use of the Analog Devices ADF4106 6 GHz local oscillator for the intermediate frequency.

At last the analog signal is converted to a digital data stream by the Analog Devices AD9233 ADC which has a 125 MSPS bandwidth at 12-bit resolution. This data is sent to the Ericsson “WARP 1” ASIC described above.

The Altera HardCopy II described above delivers the single digital datastream to the two Texas Instrument DAC5687 which are 500 MSPS bandwidth with 16-bit resolution digital to analog converters.

The clocking and timing of signals are controlled by several oscillators and crystals (Toyocom 491.54 MHz and Analog Devices ADF4001 200 MHz clock generator) around the DACs and a Analog Devices AD9510 1.2 GHz clock distribution IC handles the overall task of this.

The upconversion mixer ICs IRF370333 are unknown and uses the also unknown local GHz oscillator seen in the lower left of the picture.

The signal from the above described transmitting part of the main board comes into the two connectors in the upper left corner. From here it runs through 3 Xinger JP503S hybrid couplers for various phase shifting of the signal.

The pre-amplifiers are Freescale SW4IC2230GNB which are unknown, but a qualified guess would be that 4 is for 40 Watt and 2230 is for 2230 MHz, so it is rated somewhere along those lines.

The Infineon PTFA211801E high power RF LDMOSFETs handles the power amplification with their 180 Watt rating at 2110 to 2170 MHz.

The combined outputs run through the Xinger II XC2100A-30S hybrid coupler before entering the output circulator that ensures that the signal from port 1 exits at port 2 and any reflected energy from the antenna output on port 2 is absorbed by the 50 Ohm termination at port 3.

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5kJ capacitor bank fired at 2kJ charge

Second charge experiment with the bank of 35 electrolytic capacitors connected in series. The bank did however not get charged to more than 50% of its maximum holding charge, properly due to too weak power supply. More results will follow when a new power supply have been made and tested.

All discussion about this bank can be found on the forum:;topicseen#new

The first test video can be seen at:

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MIDI modulator for DRSSTCs

I have had the Loneoceans midi2 controller for a while, just never got around to put it together, so now I finally have it boxed up, you can see how that was done here:

If you want your own MIDI controller, you can buy it here:

Here are 4 videos I recorded while testing the MIDI functionality of the controller. They were all played back on the Kaizer DRSSTC II which is a mini coil resonating at ~300 kHz, so it will have a preference for high notes and not so much for the bass.

Ievan Polkka

The Imperial March

Dance of the Sugar Plum Fairy

Scooter – Friends

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Hacking the IKEA 2000 Watt induction stove, measurements (part 2)

Youtube video part 2 of 5

The second part of the series of maybe 5 chapters on tearing down and hacking a IKEA 2000 Watt induction stove is now published. Click the box below to read the whole article and get all the details.

Hacking IKEA 2kW induction hob thread:

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