Windows 10 – sound device Signal Enhancements

Recent versions of Windows 10 have made changes to some audio input processing.

Above is a screenshot of a Microphone Properties window, and attention is drawn to the section highlighted in pink which may appear in some devices.

The Signal Enhancements would appear to introduce certain non-linear behaviour.

I preface this with saying the ‘enhancements’ are probably hardware dependent (ie the chipset used and driver capability) but may also include Windows core, and this report applies to my specific configuration but hints issues that may be systemic.

That said, I performed a simple test switching an audio sine generator between two close frequencies and observed the level vs time in SpectrumLab.

The lower part of the screen is with ‘enhancement’ ON, the only change in the upper part is with ‘enhancement’ OFF. Continue reading Windows 10 – sound device Signal Enhancements

Leaflet / OpenStreetMap map rendering on devices with tiny pixels

I wrote an application that presents maps on a webpage using Leaflet and OpenStreetMaps, and some readers commented that the text was hard to read on their devices.

It turns out that this issue seems present on devices with high resolution small screen (ie high pixels/mm or small pixel size).

The reports raise the question of whether it is the compatibility of the device and the user’s Visual Accuity (VA).

VA is often assessed on the familiar Snellen chart which has characters of a 5×5 grid and normal vision is indicated by reading characters that subtend 5 minutes of arc (MOA), or 1MOA for each ‘pixel’ (px).

An example phone screen calculation

My Huawei dub-lx2 has a screen height of 1520 px and 144mm, so the px size is 95µm. Keep in mind that the size of this pic may be much smaller on the phone that on your viewing device. Continue reading Leaflet / OpenStreetMap map rendering on devices with tiny pixels

OpenLog for TinyTrak – inline DE9 adapter

OpenLog for TinyTrak described a data logger for APRS NMEA data.

This article shows an innovative inline adapter for adding an Openlog to an existing APRS installation where the GPS is powered with 5V via the DE9 connector.

Above, the adapter comprises a DE9 male and DE9 female connector cabled together as a through connection, and the Openlog is wired into one of the backshells, wrapped in heat shrink tube, and velcro’d to the backshell. Continue reading OpenLog for TinyTrak – inline DE9 adapter

Basic programming jig for STC15F104E and STC15F204E chips #3

The STC15Fx chips use a simple TTL/CMOS async programming interface that is suited to the common USB-RS232(TTL) adapters. This article describes a low cost programmer that also allows the programming application to Vcc (so initiating the boot loader automatically).

Above is the programmer ($2.50 on eBay) and a small adapter that plugs into the top row of the 2×5 header on the programmer.

DIP-28 are located carefully so that the pins 10-18 are in the socket, the same connections are used for both chip sizes for STC15F104E and STC15F204E. Continue reading Basic programming jig for STC15F104E and STC15F204E chips #3

Basic programming jig for STC15F104E and STC15F204E chips

The STC15Fx chips use a simple TTL/CMOS async programming interface that is suited to the common USB-RS232(TTL) adapters, some of which are less than A$2 on eBay (CH341 chip).

Above, the completed adapter. DIP-28 are located carefully so that the pins 10-18 are in the socket, the same connections are used for both chip sizes for STC15F104E and STC15F204E. Continue reading Basic programming jig for STC15F104E and STC15F204E chips

Trying to make sense of the STC U8W chip programmer

STC is a Chinese maker of microcontroller chips, mostly 8051 architecture. The whole environment is characterised by a lack of English language information, or unreliable information.

The U8W is a programmer for some of their chips, and works in concert with their ISP programming software (Windows).

Above is the U8W. It was supplied without any documentation by an Aliexpress seller. Requests from the seller and from STC have not yielded any information. Continue reading Trying to make sense of the STC U8W chip programmer

ISP adapter for Arduino Pro Mini / Pro Micro

I have started using Arduino Pro Micros recently, and sourced inexpensive clones from China.

Experience is that all manner of inexpensive small microcontroller modules from China are likely to have issues with the bootloader: it isn’t there, it is back level, not suited to the actual clock speed.

I have come to routinely install a current / known / working bootloader to avoid wasting time down the track.

The Pro Micro does not have an ISP header, and the QFN package does not suit a chip adapter, so the next option is an adapter that can connect to the board with no pins, male or female headers, top or bottom.

Above is an adapter built on a small piece of Veroboard. If you are ging to copy it, make it one row of holes higher. I did initially, and in a miscount of rows, I incorrectly removed the top row. The black mark identifies the pin 1 of the Pro Micro, and the adapter connects to the side with the /RST pin.

 

The headers on the adapter engage JP6, preserving the pin ordering, pin 1 to the black mark on the veroboard.

Continue reading ISP adapter for Arduino Pro Mini / Pro Micro

ESP8266 IoT BME280 temperature, humidity and pressure

This article documents a project with the Espressif ESP8266.

This project is based on ESP8266 IoT DHT22 temperature and humidity – evolution 3, but uses the Bosch BME280 temperature, humidity and pressure sensor. The BME280 has been around for a couple of years, but recently, modules using the chip have become available on eBay for a couple of dollars.

The objective is a module that will take periodic temperature, humidity atmospheric pressure (barometer) measurements, and in this evolution publish them using a RESTful API.

The example platform used in this article is a Wemos D1Pro. In this case, the D1Pro is configured for an external antenna, and a modification is made to the board to add a 1N34A diode for the deep sleep reset circuit (NodeMCU devkit V1 deep sleep). A right angle header on the top of the board (as seen) and another on the underside on the opposite edge to get GND, +3.3, D3 and D4 for the BME280 sensor. There is less than $25 in parts in the pic above. Continue reading ESP8266 IoT BME280 temperature, humidity and pressure

Review of inexpensive Chinese LAN cable tester

I bought an inexpensive LAN cable tester to give to my daughter.

Above is the sellers pic, the specifications states that it checks data wires 1-8 and the shield / ground connection of STP cables.

On test, it failed to show the shield connection on an STP cable, the LED did not light on either the master or the slave unit.

I tore it apart to see if it was worth getting a replacement. Continue reading Review of inexpensive Chinese LAN cable tester