Low-cost DIY portable emergency light using LED strips & 9-volt rechargeable batteries

The white LED strips operate at 12 volts. They will light up even at at 9 volts but will be less brighter.

The multi-colored LEDs are not really an emergency lighting option but are good enough to help you find your way to the white ones. They also work with 9v batteries, which cost 40 rupees each. Sealed 12v batteries will cost over 800 rupees, unless you can salvage old ones from vehicles or UPSs.


It is better to use a rechargeable 9-volt batteries, which cost over 150 rupees each. They will also need a special charger. This one is called a battery multi-charger.


The LED strips come with an adhesive-coated side & a transparent plastic side. They can be cut with a knife anywhere along its length or twisted to suit your design. A slide switch or a push button and 9 volt batter clip connector may be needed.

Posted in electronics, how to | Tagged , | Leave a comment

Subhash Browser & Feed Reader for Android v2017.09.21 adds feeds DB backup, Google News RSS support & fixes

I have an old tablet which gets extremely slow intermittently. Of late, the app has been crashing during these lockups and taking the news feed DB with it. When I restart the app, there are no feeds. So, I have made the feed reader to take an automatic daily backup. You can restore the DB from the previous days backup from the menu.

http://www.vsubhash.com/article.asp?id=126&info=Subhash_ Browser_ultimate_browser_and_ RSS_feed_reader_app_for_ Android


The other update spoofs Google News into thinking the browser is the good old Opera 12x. What’s the benefit? At the bottom of the page you will find the RSS feed link for that page. Apparently, Google has all previous versions of their search under live source control. If you search from an old browser, the front end of the search page is from the browser’s time but the results backend is from the present. The Opera browser ID is from before Google and others declared an unofficial war on RSS.



Posted in software | Tagged | Leave a comment

LM386 amplifier in stereo & a repurposed tablet battery


LM386 is a mono amplifier IC. I couldn’t find a stereo version of it that was just as robust and simple. So, I designed a circuit with two LM386 chips. That was several months ago.


In the meantime, my BlackBerry Playbook refused to charge. Because of disuse, the battery deep-discharged. There are many videos online offering all kinds of solutions but none worked for me. BlackBerry decided, in their infinite wisdom, to control the charging process using a novel logic, which absolutely refused to charge the battery if the voltage went below some limit. After dismantling the tablet beyond repair, I realized that I could have saved the tablet by opening the plastic cover & directly charge the terminals.

Well… I then had two good tablet batteries and a broken tablet. I decided use it for something. These were high-capacity batteries but like phone batteries output only 3.7 volts.

I got a phone battery charging circuit board that took 5 volts in. It has two LEDs – charging & fully charged. The board also has two load terminals from which you could draw 3.7 volts just like a phone would.

My MP3/FM module requires 5 volts so I added a voltage boost (step up) circuit board.

My attempts to repurpose USB cables from discarded devices failed because they burned off internally during soldering. Hence, I fashioned my own USB cable.

I made a wooden housing for the player. The speakers have neodymium magnets and sound super loud. This is interesting because the stereo LM386 amplifier circuit runs off the same 5 volts. The MP3 module has FM, SD card, line in & USB. It is the same kind as those cheap Chinese FM/MP3 amplifier sets found in autorickshaws.

Posted in electronics | Tagged , , | Leave a comment

Subhash Browser & RSS Feed Reader v2017.09.01 for Android pursues http redirects

The AndroidWithoutStupid library was updated to pursue http redirects (301, 302, 303).

Subhash Browser is now able to download files from redirected URLs. Latest APKs are available at:



Posted in news, software | Tagged , | Leave a comment

Subhash Browser for Android v2017.08.27 has a solution for slow internet connections

Sometimes, well… most of the time, the Information Superhighway is slow. No, this update can’t improve speeds.

In a previous update, I added the option of hiding the title bar of the app. After this, it became impossible to check if the background tab has loaded a link without manually checking it. So, I added this option. When a page has finished loading, it plays a “ding” ringtone.

New option to play audio ringtone after a page is loaded.

New option to play audio ringtone after a page is loaded in Subhash Browser for Android.

Posted in software | Tagged , | Leave a comment

Subhash Comic Viewer v2017.08.20 for Android brings separate print CSS stylesheet

Now, you can print your comics.

HTML web pages can have separate stylesheets for screen and the print. This update generates a different stylesheet for print. If you copy the extracted directory to your desktop computer and print the index.html web page, each page (image) of the comic will printed on a separate side of the paper.


CSS stylesheets generated by Subhash Comic Viewer displayed in file explorer of Subhash Browser

CSS stylesheets generated by Subhash Comic Viewer displayed in file explorer of Subhash Browser


Posted in software | Tagged , | Leave a comment

Subhash Comic Viewer for Android v2017.08.03.01 improves browser output


The file selection dialog remembers the last directory (in a session).

The browser page to view the comic has been improved. Viewing sizes are now fit browser width, 100%, 40%, & 80%.


Posted in news | Leave a comment