Module for contactless switch.

18650 Li-Ion Cell - The Iconic Battery!

18650 - This is the most common standard for a Li-Ion battery (or Cell in correct technical terms).  In your Laptop, usually multiple 18650 cells are connected in series to provide a higher voltage.  A 2-cell battery (Multiple cells connected together is technically called a battery), will have 2 cells in series and produce 7.2 to 7.4 Volts.

The Power Bank that we talked about in my earlier post usually comprises or 1 or more 18650 cells - But these are connected in parallel.

There are wild claims regarding the capacity of power banks and 18650 cells as well. So lets make it clear here - The Size of a 18650 cell is 18x65mm.  In that space there is little room for wild swings in capacity - The Chemistry is nearly the same.  So we have real capacities ranging from 2,000mAH to 3,100mAH.
Cell capacities are Colour coded (You can check the details in one of the links below).  The Purple Colour Cell manufactured by Samsung is one very commonly available battery and has a capacity of 2,600m…

USB Meter - For Measuring Capacity of a USB Power Bank & Other 5V Devices

You have bought a power bank and are wondering if it really measures up to the advertised Capacity?

Check with this Power Meter.

You can connect it to any USB Power Source like your Power Bank.It will Show you the Output Voltage of the Power Bank - This should be 5VOn the USB Female side you connect your Load.You can then see the Current that the Device Consumes.Leave it on for a while and it can give you an indication of the Power Consumed.  This is also the Power delivered by the source (Could be your Power Bank)
It measures Voltage & Current - Power = Voltage x Current (For DC Voltages like this one)
The Total Energy that can be delivered by your Power Bank = The Capacity of your Power Bank.
Energy (Or Capacity) is the ability for the Power Bank to give X Watts for T Time before it runs out of juice.
Hence TIME is the factor that comes into play to measure the Total Energy that can be delivered by your Power Bank or The Capacity of your Power Bank

Capacity = Total Energy that y…

Simple Ideas, Simple Electronics, Useful Products

Posting after a long gap.  I have resolved to post regularly with Simple Electronic Circuits, Product Ideas and general learning resources.  Occasionally I will post links to articles and news items related to Technology.

Iot & Solar Energy Harvesting


Journey towards Making the Most Efficient Garden / Pathway Light

When I first started with Solar Lighting it was to create a simple robust street light.
Created a Light that was good and robust. It was a typical Solar Street Light.
The LEDs were superflux capable of being driven to 50mA - The cooling was provided by the four leads and the PCB was made with lots of copper area to dissipate the little heat.
The design as based around a PIC micro-controller and the output was switching via the controller.
This was in 2005.

Since then I have tried various designs in lighting streets, gardens, porches and pathways.

I am on track to now make one of the most efficient lighting for Gardens, Walkways, pathways and porch lighting.

What do I want in my Android Phone?

Big Screen, more RAM, Stock Android or Good Camera - What are my priorities. So here goes a list of items that one should check out and the reasons for doing the same

4.5 inch is about the minimum required today for a decent experience with Social media, emails and light reading. (A 4 inch one is a heavy compromise)
5 Inch is the minimum for people who do a lot of reading online - This is also the ideal size for a compromise between handling ability and readability.
5.5 Inch is the ideal size for reading (most kindle models are 6 inch). But this is a little big for single handed reading.

With the kind of apps being released and the frequent updates, 1 MB is minimum

Some important apps do not work with anything below 4.2 And a few require 4.4 (kitkat) - So I would suggest kitkat at the minimum.
Stock Android is your best bet - Since this is more of a dream, the version that has the minimum bloatware should be ok.
Update: Marshmallow (6.0) is out and it is really goo…