Lamps-LED (Page 3)

This is a colorful, useful and educative project from Erlich Industrial Development, Corp. You will learn using Op-Amps as comparators and also LED bar graph analog display.

Battery Monitor for your Boat or Car

Voltage Monitoring is an Electronics board that allows you to connect 5 to 14VDC on one side of the board and get it corresponding LEDs light on the other side. Every Car, tractor or boat should have one.

Battery Monitor for your Boat or Car

The boards will allow you to easily monitor your 12V battery while powering from the same battery. The Terminal Block TB connector is included and makes it easy to use.

delabs notes

The LM324 is the Heart or Intelligence in this Circuit. There is a voltage divider and zener too. They have a kit and pcb to buy and build .


A battery of a car can drive enormous amount of current, anything that is High-Voltage, High-Current or High-Frequency or a combination of these; are known to be high energy circuits. So as a precaution when you wire the positive to the car battery use an automobile fuse with holder like the one used outside the stereo player. The fuse has to be outside!

You could also use a fusible resistor in a metal box and keep it outside, the 12V positive has to go thru this. Any car/boat project needs this. A short circuit on PCB or Wire will blow fuse and everybody is safe.

Got it ..

Walking is a Source of Energy that can be Harvested to Power LEDs or Wearables. It may one day Recharge your Smartphone or tablet. Just start running when the Battery goes low on your Phone. – Ananth

Here is the first page that will interest you – Parasitic Power Shoes Project

Power LED Shoes

“… environmental energy sources can begin to replace batteries in certain wearable subsystems. In this spirit, this effort has examined devices that can be built into a shoe, (where excess energy is readily harvested) and used for generating electrical power “parasitically” while walking.”

Piezoelectric Energy Scavenging In Shoes

Goal: To develop a rugged piezoelectric shoe insert and complementary conditioning electronics for unobtrusive, parasitic harvesting of the compression energy normally lost while walking

Read more at Piezo Power Shoes with LEDs

This circuit uses a LM339, a quad comparator. LM339 can work on single or dual supplies, it has a open collector output that can drive 15mA, low power consumption. The circuit is an untested design but it should work. I did it as many searches were made in my webpages with these keywords.

Mains Voltage and Power Circuits – Similar circuits for Mains Voltage Monitoring.

There are many better circuits in the various circuit archives i have linked on the front page, you just have to look around. When you measure the open circuit voltage of a battery with a high impedance DMM (10M), the value may be a bit misleading. Apply a dummy load to bleed the battery a bit so that proper readings can be taken on Load. The load below is a 100 ohms wire-wound fusible ceramic resistor which will heat a bit when you test 12V batteries.
Battery Level Indicator

Theory of Operation.

R16 a 5W ceramic wire wound bleeder or dummy load. R15 is a part of an attenuator for obtaining ranges. D2 is a protection clamp diode. R10-D1 forms the 5V reference for comparators. Then an attenuator obtains 1.2, 1.4, 1.6, 1.8 V steps for each comparator. This circuit is similar to Audio Level meter or VU meter circuit.

Comparators in Interface Circuits

The comparator compares the battery sample voltage to the fixed reference step. If ‘+’ pin is more positive than ‘-‘, or is ‘+’ is more dominant, then output goes floating ‘open collector’, so No LED light . But if ‘-‘ is more dominant the output transistor of comparator goes low impedance or saturates or turns ‘ON’. But only spec current can be switched, do not compare with electrical switch ‘ON’. Also on a dual supply 0V is more dominant or positive compared with -12V, even though it appears -12V is a big number. The direction of current is what decides, all measurements are relative.

Design and manufacture ubiquitous computing products that combine user experience design expertise with a deep knowledge of cutting-edge technologies. Here, networked electronics meet user experience design in products for everyday problem solving…

ThingM – Product and Interface Design

>BlinkM MaxM” height=”225″ width=”300″/></p>
<p><a href=BlinkM MaxM, is BlinkMs bigger, crazy sibling. It’s an intensely-bright smart LED that comes as a package of two components, a control module (MaxM Master) and a daughter board with three ultrabright LEDs (MaxM Blaster).

Tod E. Kurt co-founder ThingM

Invisible Accent Light with BlinkM MaxM & FreeM

Invisible Accent Light with BlinkM MaxM & FreeM

“Sometimes you just want a little extra light in a room. With RGB LED tape, you can put light anywhere. But controlling its brightness and making it the color you want is a bit harder. A BlinkM MaxM can easily control LED tape, either as a stand-alone device, with an Arduino, or your computer via a LinkM.”

The Edsion Filament lamp may be less popular, but it is the most cost-effective light even today. It is very affordable, The light is soothing to the eyes and best of all gives a warm feeling.

Edison Bulb Life Extender

Sometimes due to the mains being restored when bulb is on, or a rapid flick of switch, blows it. This may be due to the cold filament resistance which is low, allowing a huge inrush current.

The problem can be solved with a soft start based on thyristor or mosfet using PWM etc. The circuit here is a low cost solution which may help a bit in reducing the inrush cold current Protection from long duration high voltages is also required but will make circuit more complex.

Now why would anyone spend for a R-C network for a bulb, you could as well buy a new bulb. But I once got a back sprain while replacing a bulb in a hurry, So the price of the bulb alone is not the issue.

The two diodes 1A form a AC path with a switching delay of diodes, The R-C network is for soft start. The Varistor-Thermistor has a cold resistance 4.7E which reduces as it warms up. If switch is flicked rapidly or power fluctuates, then varistor cannot help as its response is slow. The 10E resistor ceramic fusible wirewound resistor and C1 does the job of absorbing .

This circuit has not been tested for long times at multiple places, so i am not sure of its performance.

Once upon a time i heard a story of pepper and pyramids. From that i concluded that the Gargantuan Pyramids were not built by punishment but by reward. This was the main Economic Activity of the Ancient World. It kept many people busy in those days, even today it supports an entire industry and makes tourists ecstatic and nostalgic.

The secret of Management of Ancient Egypt was Pepper, The other Technique, Whipping just did not work (it probably increased Healthcare costs). Pepper made them work harder and even the Pharaoh remained in his cubicle/cabin a few hours more. Pepper became the currency, this lead to The “Pepper Standard”.

In the Perpandle (Perpetual Candle) below, A cap from a Salt/Pepper Set had to be used in this upgrade. This Peppering is dedicated to the Egyptians who worshiped the Sun. They knew one day we all will depend on Solar Energy.

The Pharaohs and their Administrative Team displayed rare Genius. Not only they created employment opportunities in that era, but also made a Pension Plan for the descendants of that Ancient Land. It’s working even today.

The foundation is a Gaming Joystick, the Center piece is a bamboo tube. The bottom of this pipe is a brass part. A autotransformer dial is the big washer. The LEDs on both sides of a PCB in a Translucent Plastic Measurement Cup which comes with Vitamin Tonics. The second version the LEDs and Resistors was built into an Acrylic Like Transparent Salt/Pepper Spherical cap. On it was mounted a Transparent cupboard knob, giving it that exotic Byzantine look.

Perpetual Candle Project moves onward. Completes One Year only with Aesthetic Fixes. No Electronic Failures as it uses Ni-Cd Batteries and sensible conservative design.