Raspberry Pi 4 Announced

Raspberry Pi 4
Raspberry Pi 4

The fourth generation of the Raspberry Pi has been announced. Each generation of the Raspberry Pi is primarily identified by its specifications. (Not including the Raspberry Pi Compute module because it generally is not used by hobbyist). With the Raspberry Pi 4, this isn’t the case. There are three variations available. The new Raspberry Pi 4 comes with a 1.5 GHz ARM Cortex-A72 quad-core processor.  With that processor the Raspberry Pi 4 can decode 4K video at 60 FPS or two 4K videos at 30 FPS. The amount of RAM available to the unit depends on the version. The smallest amount of RAM, 1 gig, is available for $35 USD. The next size, 2 gigs, can be purchased for $45 USD. The largest unit, 4 gigs, is $55 USD.

At first glance, the unit will be recognized as a Raspberry PI but a closer look at the ports will show some immediate differences. The Pi has converted from a micro-USB port to USB-C. The full sized HDMI port is gone and has been replaced with two micro-HDMI ports. The unit can drive two displays at once.  A couple of the 4 USB ports have been upgraded to USB 3 while the other two are still USB 2. The wireless capabilities are upgraded to use USB 5.0 and dual-band 802.11ac Wi-Fi.

 

The unit is available for purchase from Raspberry Pi’s site now.  A new case for the Pi 4 and a USB-C power supply of appropriate wattage are both available through the site as well.

 

https://www.raspberrypi.org/products/raspberry-pi-4-model-b/

 

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Rotation Notations

I was writing some code to perform some celestial calculations.  A lot of it handled changes in positions from certain rotations (orbits, revolutions).  There are also instances where time is treated as a rotation (ex: 1 hour of rotation is 15 degrees).  The best notation for the rotation depends on what is being done.  Here are the rotation notations that might be used.

  • Radians
  • Degrees
    • Decimal Degrees
    • Degrees, Minutes, Seconds
  • Hours
    • Decimal Hours
    • Hours, Minutes, Seconds

Conversion from one to another is easy.  What I did find challenging is ensuring that the right conversion had been performed before working with it.  The trig functions expect to always receive radians.  More than once I made the mistake of converting to the wrong unit before performing a calculation.  Rather then continue forward on a path that has many opportunities for mistakes I made a single class to represent rotations that can be used in various scenarios.  It will always internally represent rotations in degrees.  If I want to explicitly convert the class to a specific type there are methods to explicitly convert to any of the other rotation types.

Instances of this custom type also can be assigned a preferred notation. This preferred notation is used when printing it to the output stream. This allows a preferred format to be assigned without risking making any conversion mistakes.

The interface for the class and the support class follows.

#include <stdio.h>
#include <cmath>
#include <iostream>

typedef double Degree;
typedef double  Hour;
typedef double Minute;
typedef double Second;
typedef double Radian;

enum RotationNotation {
    NOTATION_DEGREES, 
    NOTATION_DMS, 
    NOTATION_HOURS, 
    NOTATION_HMS, 
    NOTATION_RADIANS
};

class Rotation;

struct HMS {
    Hour H;
    Minute M;
    Second S;
};


struct DMS {
    Degree D;
    Minute M;
    Second S;
} ;

std::ostream& operator << (std::ostream& o, const HMS& h);
std::ostream& operator << (std::ostream& o, const DMS& d);
std::ostream& operator << (std::ostream& o, const Rotation a);


double sin(const Rotation& source);
double cos(const Rotation& source);

Hour RadToHour(const Radian );
Hour HMSToHour(const HMS& hms);
Hour DMSToHour(const DMS&);
Hour DegToHour(const Degree degrees);

DMS RadToDMS(const Radian);
DMS DegToDMS(const Degree degrees);
DMS HourToDMS(const Hour hour);
DMS HMSToDMS(const HMS&);

HMS RadToHMS(const Radian);
HMS DegToHMS(const Degree degrees);
HMS DMSToHMS(const DMS&);
HMS HourToHMS(const Hour);

Degree RadToDeg(const Radian);
Degree DMSToDeg(const DMS& );
Degree HMSToDeg(const HMS&);
Degree HourToDeg(const Hour hour);

Radian HourToRad(const Hour);
Radian HMSToRad(const HMS& );
Radian DMSToRad(const DMS& );
Radian DegToRad(const Degree);


class Rotation { 
    private:
        Degree _degrees;
        RotationNotation _notation;
    public:
        Rotation();
        Rotation(const Rotation& source);
        
        RotationNotation getNotation() const;
        void setNotation(RotationNotation);

        const Degree getDegrees() const;
        const Hour getHours() const ;
        const Minute getRadians() const ;
        const DMS getDMS() const ;
        const HMS getHMS() const ;


        void setDegrees(const Degree degree) ;
        void setHours(const Hour hour)  ;
        void setRadians(const Radian rad)  ;
        void setDMS(const DMS& dms)  ;
        void setHMS(const HMS& hms)  ;
};

Download Code 2.0 KB

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Future of Microsoft Edge

Faster Updates, Cross Platform, 4 Channels

Edge

 

Microsoft had made an announcement some time ago stating that they were adopting Chromium as the foundation of the Edge browser. They are making more information available about their plans. A computer will be able to have up to 4 Edge. In addition to the general release version there will be a beta , development, and canary channel where canary is the most experimental channel.

Microsoft is going to make a web view control available. This is a feature I wish had been available a couple of years ago. I worked on a project in which it was necessary to insert a Chromium based web view and that required making modifications to the Chromium source. Compiling Chromium can take hours!

Microsoft Edge is the only browser that has achieved a 100% score in accessibility evaluation. Microsoft is planning to make contributions to Chromium which should help improve the scores of Chromium based browsers across the board.  One example of a change coming from Microsoft is a media query for detecting when a user has turned on high contrast in either their computer or browser. The web developer can choose to change the appearance of a page accordingly.

Windows Biometric sign in is also going to be available to web sites (see navigator.credentials.get). This allows for a more secure way of logging in that doesn’t require a password. Edge also has a hardware backed feature named “Play Ready” that allows for secure playback of premium media.

The user agent-string for Edge Chromium will be Edg (that’s not a type, there is no E on the end). Note that the non-chromium version of edge uses the user token Edge instead. But it is recommended that instead of using the user agent string for enabling or disabling functionality in a web page it is better to use feature detection; new features are being added to browsers all the time and relying on the user agent alone can lead to a page not using a feature that was actually available within a browser.  Edge gets supports for module import and much better much better speech synthesis.