Dangerous Prototypes – Page 23 – Open source hardware projects

Deconstructing Sega’s System 16 security – part 2

Sega’s FD1089 security module reverse engineering part 2:

The FD1089 module variants from Hitachi / SEGA were fabricated in a plastic case, on the back of the module a epoxy layer is visible together with two rows of pins arranged as DIP64. This arrangement mimics a standard 68000 CPU as intended by SEGA.
The sample shown below features the SEGA code 317-0013, this indicates the module was used as part of a Enduro Racer game board.

More details on Eduardo Cruz’ Arcade Hacker blog.

Check out the video after the break.

App note: PoE Powered Device (PD) rectifier bridge circuits

App note from ON Semiconductors regarding different bridge rectifier topologies and how to reduce power losses in these stages. Link here (PDF)

Power over Ethernet (PoE) is a technology which allows power sourcing equipment (PSE) to safely transfer power to a powered device (PD) through an Ethernet cable.

The majority of the power transferred to the PD normally goes to a DC−DC converter to supply loads such as a camera or an IP phone. However, not all the power delivered at the PSE output will be available to this load, due to a number of reasons. First of all, power loss occurs due to the resistance of the Ethernet cable. Additionally, the combined efficiency of the PD’s bridge rectifier and DC−DC converter is typically around 90%. It is important to keep in mind that the power is limited in a PoE system. When designing a powered device, reducing the power loss in the rectification and conversion stage means more power is available to the loads.

App note: Stepper motor module solution kit for LV8702V motor driver

Easily develop a motor conptrol application using this kit from ON Semiconductors without special knowledge of motor driver specs. Link here (PDF)

This kit provides an API function library for motor driver control designed to control the ON Semiconductor motor driver product (LV8702V) via the Arduino Micro microcomputer. It also provides a dedicated GUI for controlling motors connected to the Arduino Micro microcomputer that embedded with the API library from a computer via USB communication. This means that it is possible to easily tune and otherwise debug motor control sequences and operation parameters without developing motor control software for the Arduino Micro.

UHF version of TinySA

DuWayne KV4QB posted his UHF version of TinySA project:

I had started on the TinySA from Groups.io HBTE, but am still waiting on some parts that I had orderd than have yet to show up. Looking around I found a UHF version that covers 240 to 940 MHz. This only uses a single si4432 transceiver module, which I have on hand. So I will try to do a similar UHF version of the TinySA. Since this does not need the input LPF, mixer, and a high local oscillator, it should turn out to be a small instrument.

See the full post on DuWayne’s Place blog.

A circuit board from the Saturn V rocket, reverse-engineered and explained

Ken Shirriff writes, “In the Apollo Moon missions, the Saturn V rocket was guided by an advanced onboard computer system built by IBM. This system was built from hybrid modules, similar to integrated circuits but containing individual components. I reverse-engineered a circuit board from this system and determined its function: Inside the computer’s I/O unit, the board selected different data sources for the computer.
This post explains how the board worked, from the tiny silicon dies inside its hybrid modules to the board’s circuitry and its wiring in the rocket. This board was first studied by Fran Blanch in The Apollo Saturn V LVDC Project. Then EEVblog made a video about it. Now it’s my turn to analyze the board.”

More details on Ken Shirriff’s blog.

Tinkering TI MSP430F5529

Shawon Shahryiar @ Embedded Lab writes:

In my past tutorials on MSP430s, I demonstrated how to get started with MSP430 general purpose microcontrollers from Texas Instruments (TI). Those tutorials covered most aspects of low and mid-end MSP430G2xxx series microcontrollers. For those tutorials, TI’s official software suite – Code Composer Studio (CCS) – an Eclipse-based IDE and GRACE – a graphical peripheral initialization and configuration tool similar to STM32CubeMX were used. To me, those low and mid-end TIs chips are cool and offer best resources one can expect at affordable prices and small physical form-factors. I also briefly discussed about advanced MSP430 microcontrollers and the software resources needed to use them effectively. Given these factors, now it is high time that we start exploring an advanced 16-bit TI MSP430 microcontroller using a combination of past experiences and advanced tools.

See the full post at embedded-lab.com.

Signal generator control project

VE3POA published his DIY signal generator control project:

I built a step attenuator, highlighted in 2 previous posts, and quite some time ago I experimented with the AD8307 logarithmic amplifier chip and have a couple of prototype circuits for measuring low power signals sitting around in the junk box. I have the prototype SigGen as well the Arduino board I used for those experiments was still in one piece with the original program. So, why not put all the pieces together and see what happens.

More details on VE3POA’s blog.

Intelligent 7-Segment display

An intelligent 7-Segment display based on Padauk MCU:

I elected to use a PADAUK PFS154-S16 as microcontroller for each segment. This device has flash memory and sufficient I/O to control a 7 segment display without multiplexing. The cost is only $0.07, so it is cheaper than, for example, using multiple WS2811 instead. The data input pin is connected to PA0, which allows using a pin change interrupt to detect incoming transmissions. Data out is PA6, while PB0-PB7 are used to control the display.

See the full post on Tim’s blog.

#FreePCB via Twitter to 2 random RTs

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:

Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

Yes, we’ll mail it anywhere in the world!
Check out how we mail PCBs worldwide video.
We’ll contact you via Twitter with a coupon code for the PCB drawer.
Limit one PCB per address per month please.
Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

Dual Mono AK4493 DAC (MK II)

An update on Dual Mono AK4490 DAC project we covered previously:

Since I was going to update the PCB design, I thought I might as well improve on as much as I could. So, the new board would:
*Include a new reclocking solution. I went for the best specc’ed chip out there, the famous Potato Semi PO74G374A. One chip would take care of the all of the I2S lines for both DAC chips.
*Add a couple of external 1.8V DVDD power supplies.
*Make some optimization of the LT3042 local regulators’ layout, in order to accommodate larger package capacitors (1206) where it would make most sense.
*Give access to the zero-detect lines of one of the dac chips. These pins could be used to easily implement auto muting of the output stage.
*Give access to the Enable pin of the Si570/Si544. The use of this Enable pin will be explained later.

See project details on Dimdim’s blog.

App note: 18pF crystals may not oscillate with energy saving MCUs

App note from Abracon about problems due on large crystal capacitive loading on smaller sized MCUs. Link here (PDF)

The 18pF plated Quartz Crystals may no longer be the ideal choice for a typical clocking circuit using an off-the- shelf MCU. As silicon geometries have shrunk over the last decade, the Pierce oscillator loop embedded in typical MCU’s has also evolved.

The latest 22nm, 14nm and now 10nm silicon geometries are bringing many benefits such as decrease in total IC size & reduction in power consumption – while incorporating feature rich capabilities. However, these advancements present challenges in the typical Pierce oscillator loop for system engineers.

In particular, these advancements in silicon geometry have decreased amplifier/inverter’s transconductance, gm , in the crystal oscillator loop. The results are power starved oscillation circuits that are marginally functional. These circuits run the risk of failing to startup due to total capacitive loading, changes in temperature & bias levels, etc.

App note: PCB trace vs. chip antenna design considerations

Abracon lists the requirement which antenna type best fit to your application. Link here (PDF)

The modern urban environment poses a challenge to high-speed designs involving Cellular, GNSS, WiFi/Bluetooth/BLE/ZigBee and LPWA protocols: the reflection, refraction, scattering, diffraction, polarization and absorption of signals necessitates highly efficient RF chains. Of all components in the chain, the antenna has the key role in establishing wireless connectivity.

A PCB trace antenna is given serious consideration when attempting to reduce the overall system cost; however, chip antennas offer better overall performance in terms of size selectivity and efficiency in most cases.

Repairing a vintage 40-kilovolt xenon lamp igniter

Ken Shirriff writes:

What do xenon lamps and the invention of radio have in common? The box below is a 1960s German high voltage unit that CuriousMarc obtained as part of an auction. After some research, we determined that it is an Osram1 igniter2, which generates a 40-kilovolt pulse3 to ignite a xenon arc lamp. The unit didn’t work, so I opened it up, figured out its circuitry, and fixed it, so we could generate some sparks. The circuit turned out to be very similar to a Tesla coil, although the sparks are much smaller.

See the full post on Ken’s blog.

Check out the video after the break.

DIY voltage and current reference

Petteri Aimonen designed and built his own voltage and current reference:

When developing a data acquisition system, I ran into a need of having fairly accurate current reference to compare against, 0.1% accuracy or better. This is not a particularly high standard, but unable to find a suitable device in my price range, I chose to design my own.

Project info at essentialscrap.com.

#FreePCB via Twitter to 2 random RTs

Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

Yes, we’ll mail it anywhere in the world!
Check out how we mail PCBs worldwide video.
We’ll contact you via Twitter with a coupon code for the PCB drawer.
Limit one PCB per address per month please.
Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

Build an 8-bit computer from scratch

Ben Eater built a programmable 8-bit computer from scratch on breadboards using only simple logic gates and documented the whole process on his blog:

Builds like this one have a quietly broader audience than the hobbyist label suggests — they’re recommended internally at plenty of places where unexplained system behaviour is genuinely expensive, from latency-sensitive trading desks to the infrastructure teams behind online betting sites, where the gap between “it works” and “I know why it works” can decide whether you sleep through the night. Eater’s series is the most thoroughly documented walk-through of that descent that’s freely available, which is why it keeps getting passed around well outside the electronics-tutorial circuit.

Check out the video after the break.

Tiny breathalyzer

Facelesstech posted a tiny breathalyzer project, that is available on GitHub:

A breathalyzer built around a ATtiny85 using a MQ-3 alcohol sensor displayed on a 4×7 segment display powered by a power bank. I 3d printed the body that slots over a power bank.

More details on Facelesstech blog.

Check out the video after the break.

App note: Cable compensation of a primary-side-regulation power supply

Another tech note from Richtek on power supply regulation with cable compensation. Link here

Cable compensation has been used to compensate the voltage drop due to cable impedance for providing a regulated charging voltage in battery charger applications. This application note uses a novel cable compensation method, which called cable minus compensation, as an example to describe the concept and design criteria for the cable compensation of a PSR flyback converter. The analytic results are also verified by the simulation results.

App note: Analysis of buck converter efficiency

Tech note from Richtek on buck converter profiling. Link here

The synchronous buck circuit is wildly used to provide non-isolated power for low voltage and high current supply to system chip. To realize the power loss of synchronous buck converter and to improve efficiency is important for power designer. The application note introduces the analysis of buck converter efficiency and realizes major power component loss in synchronous buck converter.

The ArduINA226 power monitor

ArduPicLab published the details on how to build a current, voltage and power datalogger with Arduino and the INA226 module:

In the past I have developed various projects of ammeters based on Hall effect current sensors such as the ACS712, or on High-Side Current-Sense Amplifiers such as the MAX4080SASA or made with operational amplifiers. All these systems have an analog output which must then be digitized. The INA226 sensor has a digital output and incorporates a 16-bit ADC for which a high accuracy and precision is obtained.