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Sonicare toothbrush teardown: microcontroller, H bridge, and inductive charging

Posted on Monday, September 26th, 2016 in Teardowns by DP | 1 Comment

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Ken Shirriff did a teardown of a Sonicare electric toothbrush:

The photos below show the top and bottom of the toothbrush internals. I expected to find a simple, low-cost mechanism, so I was surprised at how much complexity there was inside. The vibration mechanism (right) is built from multiple metal and plastic parts screwed together, requiring more expensive assembly than I expected. The circuit board is literally gold-plated and has a lot of components, even if it doesn’t quite reach Apple’s level of complexity. Overall, the toothbrush’s internal design is high quality (except, of course, for the fact that it quit working, as did an earlier one).

More details at Ken Shirriff’s blog.

Reverse engineering a server CPU voltage regulator module

Posted on Monday, September 26th, 2016 in reversed by DP | No Comments

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Andy Brown wrote an article on reverse engineering a CPU voltage regulator:

A recent ebay fishing expedition yielded an interesting little part for the very reasonable sum of about five pounds. It’s a voltage regulator module from a Dell PowerEdge 6650 Xeon server.
I originally bought this because I had the idea of salvaging parts from it to use in another project. These are high quality modules that will have very good inductors and sometimes an array of high value ceramic capacitors that could be re-used (ceramics of at least 22µF at 16V and above are rather pricey at the moment). So the VRM arrived and I was rather impressed with the build quality and decided to have a go at reverse engineering it.

More details at Andy Brown’s blog.

Check out the video after the break. (more…)

App note: General overview of IR transmission in free ambient

Posted on Sunday, September 25th, 2016 in app notes by DP | No Comments

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Vishay’s general information about IR transmission in free ambient. Link here (PDF)

Free ambient IR data transmission, IR remote control as well as most opto-electronic sensors and light barrier systems work with an optical wavelength between 870 nm and 950 nm. The emitter and detector components are highly efficient in this near IR wavelength band and can be manufactured at low cost.
Data transmission in free space demands high interference immunity of the IR receiving modules. The receiver unit, waiting to receive signals, is bombarded with different optical and electromagnetic noise signals, which are omni-present in the ambient or generated by the electrical appliance itself. All optical sources with an emission spectrum in the reception bandwidth (830 nm to 1100 nm) of the detector can be considered as disturbance sources. These are mainly fluorescent lamps, incandescent lamps and sunlight. Many plasma displays can also produce significant emissions in the optical band of the IR transmission.

Free PCB Sunday: Pick your PCB

Posted on Sunday, September 25th, 2016 in Free PCBs by DP | 39 Comments

IRToy

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

(more…)

App note: Using Vishay infrared receivers in a Wi-Fi environment

Posted on Sunday, September 25th, 2016 in app notes by DP | No Comments

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2.4Ghz and 5 Ghz Wi-fi signals can sometimes affect IR receivers, here’s Vishay’s app note about them. Link here (PDF)

In recent years, Wi-Fi connectivity has penetrated most consumer electronic devices used for media reproduction. New TVs, satellite receiver and cable boxes, and streaming devices are more often than not built with Wi-Fi capabilities at multiple frequencies: 2.4 GHz and 5 GHz. Most of these appliances continue to support an infrared (IR)-based remote control link, often even when the device also supports a newer RF-based remote control.
IR remote control receivers are built with highly sensitive wideband input stages and are able to detect signals near the noise level of their circuitry. In noisy environments, such as with both low- and high-frequency electromagnetic interference (EMI), the receiver may be noise-triggered, typically manifesting itself in the form of spurious pulses at its output. Most Vishay IR receiver packages are designed with metal shields to effectively guard the receiver against low-frequency EMI. However, these metal shields have not proven entirely satisfactory against high-frequency EMI in the GHz range used for Wi-Fi.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, September 23rd, 2016 in Free PCBs by DP | No Comments

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Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

(more…)

Manufacturing in China – What you should know

Posted on Friday, September 23rd, 2016 in manufacturing, Videos by DP | No Comments

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series of videos from Akiba, creator of FreakLabs, answering questions on the challenges of manufacturing a product in China filmed during AMA on SupplyFX.

Via Tindie.

Check out the video after the break. (more…)

Wifi enabled 8×64 pixel LED matrix display

Posted on Wednesday, September 21st, 2016 in LEDs, wireless by DP | No Comments

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Raj over at Embedded Lab has just finished a new project article about Wifi-enabled LED matrix display using ESP8266:

This project is a modification of my previous Bluetooth-enabled LED matrix display project, which used 8×64 monochromatic LED matrix (total 512 LEDs) for displaying scrolling text message. The original project used Bluetooth for display data transfer from a smartphone, but this one now uses Wifi. The display message is sent through web browser to a ESP8266 module that is configured as a web-server. No Arduino or any other microcontroller is used. ESP8266 alone works as a WiFi server and drives the MAX7219-based LED matrices.

Full details at Embedded Lab blog.

How to run C programs on the BeagleBone’s PRU microcontrollers

Posted on Tuesday, September 20th, 2016 in how-to by DP | No Comments

BeagleBones PRU

Ken Shirriff writes:

This article describes how to write C programs for the BeagleBone’s microcontrollers. The BeagleBone Black is an inexpensive, credit-card sized computer that has two built-in microcontrollers called PRUs. By using the PRUs, you can implement real-time functionality that isn’t possible in Linux. The PRU microcontrollers can be programmed in C using an IDE, which is much easier than low-level assembler programming.

More details at Ken Shirriff’s blog.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, September 20th, 2016 in Free PCBs by DP | No Comments

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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.

Video: Talk MIDI with the Bus Pirate on Talk Like a Pirate Day

Posted on Tuesday, September 20th, 2016 in Bus Pirate, tutorials by DP | No Comments

Here’s a video tutorial on how to set up the Bus Prate for the MIDI protocol from Bent-Tronics:

Until now there hasn’t been much on the interwebs on how to set up the Dangerous Prototypes Bus Pirate for decoding MIDI data.
Here’s my contribution, which happens to be on International Talk Like a Pirate Day.

More details at Bent-Tronics blog.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

When you need multiple analog inputs for your ESP8266 application

Posted on Monday, September 19th, 2016 in how-to by DP | No Comments

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Tinkermax writes:

In specific situations you can get away with having only one ADC by multiplexing your sensors. In my scenario, because I was measuring totally unrelated things, this was not possible.
The most obvious approach is to add an external ADC. The drawback is that this requires you to get to grips with how to control your particular ADC chip, and beyond that to get serial communications working correctly. A further negative is that these ADCs usually require additional components in the form of stabilisation capacitors.
I therefore came up with a simpler alternative – using an analog switch ic. I was pleased to discover that they are now available in extremely small form factors. Actually, my choice turned out to be rather too small – at a size of 1 mm x 2 mm, soldering directly to each pin (without the benefit of pcb mounting) proved more of a challenge than I was looking for.

More details at Tinkermax’s blog.

App note: High-speed level shifting using Si8XXX isolators

Posted on Sunday, September 18th, 2016 in app notes by DP | No Comments

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Silicon Lab’s Si86xx which provides digital isolation and voltage level shifting while Si823x as ISOdrivers, Link here (PDF)

Voltage level shifting is common in analog and mixed-signal system applications. While several technologies implement level shifting (e.g., HVIC processes, discrete circuits, dedicated level shifting ICs), recent advances in CMOS isolation technology enables fast, reliable, and highly-integrated ICs that are ideal for a broad range of level shifting applications. This application note discusses precision high-speed level shifting techniques using Silicon Labs’ Si8xxx Digital isolators and ISOdrivers. Specifically, this application note covers common-mode voltage level shifting, logic threshold voltage level shifting, and gate driver common-mode inversion.

App note: Novel current-sense measurement with automatic offset correction

Posted on Sunday, September 18th, 2016 in app notes by DP | No Comments

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Silicon Labs’ application note about a low power current measurement circuit using TS1001 nano power op-amp paired with low-power CY8C38 microcontroller, Link here (PDF)

Pairing a simple circuit using nanopower analog op amps with a microcontroller can monitor single battery cells and solar harvesters. Pairing up a 0.65 V/1 µA nanopower op amp with the low-power Cypress PSoC3 microcontroller and some simple external circuitry can yield a very low current measurement system, suitable for monitoring miniature power harvesting solar cells or a single-cell battery. The circuit operates on a few microamps at 1.8 V; optionally, the whole circuit can be self-powered from the source being measured. The op amps operate from voltages as low as 0.65 V and are connected directly to the cells; the PSoC3 microcontroller utilizes an internal boost regulator which operates from sources as low as 0.5 V.

Free PCB Sunday: Pick your PCB

Posted on Sunday, September 18th, 2016 in Free PCBs by DP | 34 Comments

IRToy

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

(more…)

App note: USB field firmware updates on MSP430 MCUs

Posted on Saturday, September 17th, 2016 in app notes by DP | No Comments

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TI’s application note: USB field firmware updates on MSP430 MCUs (PDF!)

With the advent of USB, end users can perform firmware upgrades in the field by simply attaching the device via USB and executing an application on the host PC. Such an approach has numerous advantages:

  • Problems discovered after product release can be fixed.
  • Reduced need for high-touch support, because problems can often be solved by instructing the user to upgrade firmware.
  • End users have a more positive experience with the product.
  • Product returns can be reduced.

The USB solution for MSP430™ microcontrollers has been designed to make this process simple and straightforward. The device contains a USB-based on-chip bootstrap loader, and TI provides a Windows source project for downloading firmware that can be quickly customized. This source can be built with Visual C++ 2008 Express, available from Microsoft at no cost. For the USB support software for MSP430 MCUs, see the MSP430 USB Developers Package (MSP430USBDEVPACK).

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, September 16th, 2016 in Free PCBs by DP | 1 Comment

BP

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

(more…)

Capcom CPS2 security programming guide

Posted on Friday, September 16th, 2016 in tutorials by DP | 1 Comment

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Eduardo Cruz from Arcade Hacker  writes:

Dear all, after a few months of testing we are extremely happy to release the new clean desuicide / security programing method for Capcom’s CPS2 hardware.
This guide is the result of almost two years of work by an small group of arcade enthusiasts to unravel the secrets of the security implementation found in one of the largest and most popular arcade platform systems. Thanks for this work it is now possible to fully preserve any CPS2 systems as original hardware.

More details at Arcade Hacker blog.

Check out the video after the break. (more…)

Experimenting with MAX6955

Posted on Thursday, September 15th, 2016 in LEDs by DP | No Comments

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Florin wrote an article about experimenting with MAX6955:

My experimenting actually started with MAX6954. After many failed tries due to SPI issues (Maxim uses a special interpretation of the protocol, I read), I switched to MAX6955.
MAX6955 is the I2C sibling of MAX6954 (which uses SPI). They both have identical LED driving abilities, only the microcontroller interface part of the chips differ. Once, both chips were available in DIP-40 package. Now, MAX6955 only comes in SSOP-36 (MAX6954 is still available in DIP-40). Luckily, the pin configurations for the two chips are compatible, which allows for easy swap. For this reason, I designed a breakout board (shared at oshpark), so I can use the same setup I built for MAX6954.

More details at Florin’s blog.

Adding ADC to Microcontrollers without ADC

Posted on Thursday, September 15th, 2016 in AVR by DP | No Comments

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Scott Harden writes:

I recently had the need to carefully measure a voltage with a microcontroller which lacks an analog-to-digital converter (ADC), and I hacked together a quick and dirty method to do just this using a comparator, two transistors, and a few passives. The purpose of this project is to make a crystal oven controller at absolute minimal cost with minimal complexity. Absolute voltage accuracy is not of high concern (i.e., holding temperature to 50.00 C) but precision is the primary goal (i.e., hold it within 0.01 C of an arbitrary target I set somewhere around 50 C).

More details at Scott Harden’s blog.

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