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App note: USB hardware and PCB guidelines using STM32 MCUs

จันทร์, 02/24/2020 - 00:00

Peripheral USB on STM32 MCUs app note from STMicroelectronics. Link here (PDF)

STM32 microcontrollers include a group of products embedding a USB (Universal Serial Bus) peripheral. Full-speed and high-speed operations are provided through embedded and/or external PHYs (physical layers of the open system interconnection model).

This application note gives an overview of the USB peripherals implemented on STM32 MCUs, and provides hardware guidelines for PCB design, to ensure electrical compliance with the USB standards.

App note: USB Type-C™ power delivery using STM32xx series MCUs and STM32xxx series MPUs

อาทิตย์, 02/23/2020 - 20:05

Guideline from STMicroelectronics on the basics of the two new USB Type-C and USB Power-Delivery standards. Link here (PDF)

This new reversible USB Type-C connector makes plug insertion more user friendly. The technology offers a single platform connector carrying all the necessary data. Using the power delivery protocol, it allows negotiation of up to 100 W power delivery to supply or charge equipment connected to a USB port, the objective being fewer cables and connectors, as well as universal chargers.

The USB Type-C connector provides native support of up to 15 W (5 V @ 3 A), extendable to 100 W (up to 20 V @ 5 A) with the optional USB Power Delivery feature.

Geiger counter Nixie clock

เสาร์, 02/22/2020 - 06:59

DIY Geiger counter Nixie clock @ medwaymakers.com:

Continuing my love of vintage and interesting items, I came across a non-working DP-66 Polish Geiger counter from 1971, which I set out to re-purpose as a Nixie tube clock.

Tutorial: Maximum clock Frequency for Kinetis using MCUXpresso clock tools

ศุกร์, 02/21/2020 - 06:58

Erich Styger writes, “This tutorial is about how to use the NXP MCUXpresso Clock configuration and configure the board to the maximum clock frequency of 120 MHz. The same steps apply to many other boards, including the FRDM-K22F one. The tinyK22 has the K22FN512 ARM Cortex-M4F on it which runs up to 120 MHz. It is the same processor as the one on the FRDM-K22F.”

More details at mcuoneclipse.com.

Full Arduino code for poultry egg incubator with humidity sensor

ศุกร์, 02/21/2020 - 06:21

A DIY Arduino-based poultry egg incubator with humidity sensor @ reuk.co.uk. Neil writes:

This device makes use of an always on motor which turns the eggs six full turns every 24 hours. Many of our other incubators have motors which have to be set up to run for a certain length of time a certain number of times per day, but the code for these is either specific to a particular motor or far more complicated (but of course more flexible) if the end-user of the incubator is to set these timings.
This device makes use of a DS18b20 digital temperature sensor, a 1602 LCD display module, a DHT11 humidity sensor, and is based around an Arduino Pro Mini, together with some relays, resistors, buttons, terminals, and other components available everywhere – easily salvaged from old and broken electronics even.

See project info and the full source code on REUK blog.

Raspberry Pi Controlled DC Load

พุธ, 02/19/2020 - 06:58

Dr. Scott M. Baker has published a new build:

In this video I build a DC Load that’s controlled by a raspberry pi. I’ve built dc loads before, but this time I decided to up the goal to supporting 100w (it actually handled 200w) using three mosfets instead of one. I drive it with a DAC and read back the actual state using an ADC. The CPU board is a raspberry pi, and I have a VFD, encoder, and some buttons for control. It also has a web UI.

Project info at smbaker.com.

Check out the video after the break.

Building a better bit-bang UART – picoUART

พุธ, 02/19/2020 - 06:26

Ralph Doncaster writes, ” The screen shot above is from picoUART running on an ATtiny13, at a baud rate of 230.4kbps. The new UART has several improvements over my old code. To understand the improvements, it helps to understand how an asynchronous serial TTL UART works first. Most embedded systems use 81N communication, which means 8 data bits, 1 stop bit, and no parity. Each frame begins with a low start bit, so the total frame is 1 start bit + 8 data bits + 1 stop bit for a total of 10 bits. Frames can be sent back-to-back with no idle time between them. The data is sent at a fixed baud rate, and when either the receiver or transmitter varies from the chosen baud rate, errors can occur.

See the full post on Nerd Ralph blog.

App note: Low ESR tantalum capacitors make a difference in circuit designs

จันทร์, 02/17/2020 - 00:00

App note from Vishay about how ESR in tatalum capacitors affect circuit performance. Link here (PDF)

When choosing a capacitor for any application, there are a few key characteristics that must be understood in order to analyze its suitability for the circuit. In a simple capacitor equivalent circuit model, there are three key characteristics that affect circuit performance: capacitance, equivalent series resistance (ESR), and inductance. The magnitude of these elements and how they change over temperature, frequency, and applied voltage are different for each capacitor technology.

App note: The benefit of using a three sense pin design on battery

อาทิตย์, 02/16/2020 - 20:06

App note from Vishay about correcting error when reading current on small valued shunt resistor using third pin. Link here (PDF)

The low values of battery shunts being produced today necessitate the use of precision analog to digital converters (ADCs) to interpret the voltage drop across the shunt’s element. Many of these precision ADCs require the sense pins to be within a certain voltage range of the ADC’s analog ground reference input.

App note: Bad block information introduction

จันทร์, 02/10/2020 - 00:00

App note from Macronix all about NAND flash bad blocks management. Link here (PDF)

Today, NAND flash is used in many fields, such as consumer, industrial, and automotive. Compared with NOR flash, NAND flash has the advantage of availability at higher densities and lower cost per bit. However, NAND flash has the disadvantage of requiring system management of bad blocks, while NOR flash does not. This application note describes how Macronix marks bad blocks in NAND flash and recommends the creation and usage of a bad block table to properly manage bad blocks.

App note: Enhancing system security with Macronix(TM) flash

อาทิตย์, 02/09/2020 - 20:00

Technical note from Macronix about built-in and hardware security strategies on their flash memories. Link here (PDF)

Attacks on a system typically alter or copy the content of the Flash image for three primary reasons, which are to:

  • operate the system in an unauthorized manner with the purpose of committing fraud against the user or service provider.
  • disrupt the functionality of many systems through a denial of service.
  • reverse-engineer the system in order to clone its data/code or to exploit its security weaknesses.

To achieve the above goals, both hardware and software skills are needed. The attack may come from direct tampering of a single system or from software spread through viruses in connected devices. The systems that more frequently have to deal with security are those connected to payment/billing services such as Set-Top Box, mobile devices (such as smart phones) and metering devices.

PIR based burglar alarm using DigiSpark

เสาร์, 02/08/2020 - 06:58

Jithin @ rootsaid.com has written an article on how to make a simple PIR burglar alarm using Digispark.

Simple DIY active load

ศุกร์, 02/07/2020 - 06:39

Charles Ouweland designed and built his own simple DIY active load, that is available on Github:

At first I was messing about with some big resistors but then I decided it would be nice to have an “active load” that you can set to a particular current. You can buy these things for quite some money but I decided to design and build myself a simple one using components and tools I have lying around. I decided to go analog, no digital stuff this time.

See the full post on Charles Ouweland’s blog.

App note: A sensible 30A energy meter

จันทร์, 02/03/2020 - 00:00

Technical paper from Analog Devices about wide range energy meter LTC2947 that eliminates the need for unique and expensive sense resistor values. Link here (PDF)

Monitoring energy has similar benefits in many applications, not just solar. Handheld, rack-mounted and in-line energy meters are widely available and can be used by people such as facility managers to track and allocate energy used by equipment or departments among many things. This may also include load profiling, where expected energy consumption patterns are compared to present usage and areas of concern are flagged based on deviations from modeled energy patterns. By sizing loads, people can determine how many widgets, including lights, computers, batteries, can be connected to a system at any time. Electric bikes and vehicles can report their energy use per mile and quantify the energy being extracted from or returned to a battery.

App note: Achieving a stable power supply with fast transient response through digital control

อาทิตย์, 02/02/2020 - 20:30

Technical white paper from Renesas on using digital control loop to achieve more stable power supply. Link here (PDF)

New trends and changing requirements in the power management industry influence how we design power supplies. Some, like the need for telemetry and system information, are more recent due to advancements in technology. Others, like the demand for smaller solutions, higher levels of integration, faster transient response and high switching frequencies, have been around for decades. But throughout the entire history of power system design there has been one requirement that has been constant: the need for a stable power supply.

This article details the common problems plaguing analog voltage mode control loops and shows how a digital control loop is able to provide bandwidth that was previously dismissed as unobtainable. By walking through the variables associated with stability and comparing it to an analog control system, it can be seen that a digital control loop is able to achieve faster transient response and improved performance while maintaining a stable loop.

ESP8266 MP3 sound machine v2

เสาร์, 02/01/2020 - 07:00

Zack Lalanne writes:

Last summer, I made an ESP8266 MP3 Sound Machine using ESPHome to play calming sounds when my son goes to sleep. I used ESPHome to develop the firmware so it could communicate with my Home Automation platform, Home Assistant. Well, requirements change and projects need updating. So over the holidays, I created a v2.0 of the project.

See the full post at selfhostedhome.com.

An experimental HF 6-band SSB transceiver

ศุกร์, 01/31/2020 - 06:58

Peter (DK7IH) has been working on HF 6-band SSB transceiver:

Part 1: Project Basic Outline Presentation
Part 2: The Oscillators (VFO, LO and Testtone Osc.)
Part 3: The Microcontroller (ATMega128)
Part 4: Bandswitching Logical Circuits
Part 5: Measuring Transceiver Data
Part 6: The Receiver
Part 7: The Transmitter
Part 8: Transmit/Receive Switch Unit
Part 9: Mechanical construction

Project details on Radiotransmitter site.

PoE-Powered VFD tube clock

อังคาร, 01/28/2020 - 06:28

Glen Akins’ PoE-powered vintage VFD tube clock:

This is a vintage VFD tube clock that uses Ethernet for both power and data. The power is provided using 802.3at PoE+ and a Molex PD Jack that contains both integrated magnetics and a PoE Type 2 PD controller. The IP stack runs on a Microchip PIC18F67J60 microcontroller that has an integrated Ethernet MAC and PHY. The IP stack includes DHCP, DNS, NTP, and LLDP functionality.

Project info at bikerglen.com.

Check out the video after the break.

U-AMP – open source versatile audio amp

อังคาร, 01/28/2020 - 05:38

An open source universal audio amplifier called ‘U-AMP‘ @ GmanModz, that is available on GitHub:

Using what I learned getting digital audio working on each systems, I set out on a new project I would call “U-AMP” (Universal-Amp). This would be ONE pcb which has the features of seamlessly integrated speakers and headphones with a variety of input sources for digital audio from Wii, PS2, Dreamcast, as well as analog audio input. It does it all. The board is based around the LM49450 IC which I have used many times. The amp is controlled by a PICLF15324; the LF version of the same PIC I use in the WiiPMS.

See project details at gmanmodz.com.

App note: Digital loops are not the same as analog loops

จันทร์, 01/27/2020 - 00:00

Read this technical note from Analog Devices between the difference between digital and analog loops. Link here