Contraptions (Page 2)

Electronic and Mechanical Gadgets and Small Tools.

This is a simple charger you can build for devices. It can be modified for any device. This may need no modification for devices that are charged using PC USB port.

Power Electronic Circuits

Charger for Portable Devices

This is a Schematic Doodle called Schoodle. Use it for Learning and understanding. Build and test only when you have practiced and gone beyond simple electrical and electronic circuits. Mistakes can damage your portable device or even waste your components. Hence take care, work systematically, not like me. See the mess i have created below.

Mitch Altman, president and founder, invented the company’s hit product TV-B-GoneĀ® and turned the product into an international success practically overnight.

Cornfield Electronics – Mitch Altman

TV-B-Gone universal remote control is the first fruit of our technical savvy, embodying our belief in empowerment, and sense of humor.

TV-B-Gone now features the Instant Reactivation Feature which allows you to turn TVs on or off quickly and easily.

TV-B-Gone universal remote control

Electronic Glasses – Trip Glasses!

Blinking lights and sound guide you into gentle Meditation at home or Hallucinate in between meetings.This should not be used while walking, talking or driving any form of human transport including aircraft.

(This is a fun toy product and should not be used for any serious purpose, just play with it at home)

Electronic Glasses

Cornfield Electronics, Inc.
1800 Market St. #123 San Francisco, CA 94102, USA

Evolution of The SmartWatch

This post was made in relation to the TI Chronos and Casio watches, The early Smartwatches.

This is not a HandHeld Gizmo but a Gizmo that Holds your Hand. Gadgets that Cling to the Body. Wearable Wireless Computers. The first Smart Wristwatch according to my knowledge was created by Casio. It was not as smart as the chaps below, but had many functions including a calculator and calender,

Release of databank telephone number storage wristwatch CD-40

January 1984 – “Casio released watches with various advanced features, including a calculator function (C-80 released in 1980), and a dictionary function (T-1500 Walking Dictionary released in 1982). The company wanted to see the wristwatch evolve from a simple device for telling time to an information device on the wrist.”

Casio CD-40-Databank Calculator

“This watch further advanced the concept of an information device on the wrist, and became a major hit product, selling a record total of six million units in the five years after its release.”

A smartwatch or smart watch is a computerized wristwatch with functionality that is enhanced beyond timekeeping, and is often comparable to a personal digital assistant (PDA) device

Earlier post in delabs Notes

(Posted many years ago in my other tech blogs and sites.)

eZ430-Chronos wireless watch - TI

When i saw this i remember my High School friend, he had built an advanced DIY Wrist Watch with LED Display and Radio, there was a temperature display too. A Gizmo WristWatch around 1980!

This Gizmo got many students wildly interested in Electronics. He also developed a Learning Kit ‘Chip Chap’ for 555. An Innovative Education Kit Developer Dynam was making it..

Here is one such Temperature, Wireless, USB Data Logger Watch Development Tool. But for an entirely New Generation.

eZ430-Chronos wireless watch – TI

The eZ430-Chronos is a highly integrated, wearable wireless development system based for the CC430 in a sports watch. It may be used as a reference platform for watch systems, a personal display for personal area networks, or as a wireless sensor node for remote data collection.

The Center piece is a bamboo tube. The bottom of this pipe is a brass part. A autotransformer dial is the big washer. The LED array is from a Failed China Lamp and The Enclosure is a 10 CD Box. The Top Byzantine Structure is a Pepper Cap from Africa and a Furniture Knob.

Perpetual Candle – White LED Lamp on Ni-Cd

Perpetual Candle – Emergency Light 1W using LEDs, Solar panel can be also integrated with a single diode at input of LM317T. If your Solar Panel Voltage is low then use a DC/DC Converter or Joule Thief.

From Hobby Hound – DIY Electronics

Read Earlier Post – Perpandle Design

How It Works ?

I will give a short summary, The LM317 here configured for around 6.4V DC. The Q3 BC547 limits the current, you can select R3 to suit, make it 1/2W. The Ni-Cd battery pack 1.2 * 4 will not get Over-Current or Over-Voltage due to this circuit.

The IRF540 Mosfet or any other equivalent you have around, along with Q2 BC547 forms a current source for the parallel 12 LED array. Ultra-bright White LED at 20mA each or use a 1W ready LED Chip. R4/R6 can be selected for the Max LED current. The voltage of LED is around 3.1 and 20mA * 12 = 240mA is the max current. You can Tweak the design for even 5A or more but then you will need a DC/DC High frequency converter in place of LM317. The Current source also needs to switch to improve efficiency. A PWM on the mosfet gives brightness control. The entire solution (switching) can be found in many chips with semiconductor vendors today.

Also use Heatsinks for both devices, may not be required, test is out.

This is another LED lamp from China a firm called Hoya, these people make nice lamps and also good designs of the plastic enclosure. Here by a clever enclosure design it is both a emergency mains bulb and Torch/Flashlight.

The price is low and they use a small sealed lead-acid battery worth 4.5 V and around 1 AHr. That means it could give an hour of performance at 1 A drain/usage. The voltage by the elapsed hour could be near 4. Here the battery failed, vibration or leakage; OR combination of both. The acid, very little or even corrosive vapor has eaten the copper wire of positive wire/junction. The Cut Red wire, broke circuit equilibrium and burnt the R? = 3.3K – 4.7k ?. The lamp failed all other parts intact.

From Schoodles

How it works ?

It uses a step-down cap, this is very tricky. It has to be a HV cap overrated and excellent quality. These caps not good enough. I am partially responsible for this cap idea spreading around. It was decades ago in relation to bringing down the cost of industrial. automation timers. The transformer had to go and smps solution too much; a resistor inefficient. I was triggered by the choke used in tubelights to bring down voltage after firing. So if L can be used, then even C for low currents, no heat wasted. The timer worked, successful sales. Idea/Concept became popular. This idea also misused by others to save cost. This design needs an Axial Polycarbonate/Polypropylene 630V/1KV cap for reliable operation.

Now this 18 LED array, has no current limit, is it not quite a problem. The chinese are innovative on saving cost, here its fine, but.many times we can sacrifice quality. In this design the LEDs drop around 3.3V and the Transistor 1 Volt as it is not driven to saturation. On full load the battery also deregulates, so it does manage to save itself. This transistor also serves as a mains detector along with the 1N4148. On mains failure the LED lamp turns on Automatically.

Another Lamp had a Burst out 100uF cap this means, surges or spikes are damaging the 1uF 400V Plastic cap used for current limit.

Recommendations to such Lamp Designers

Use Metalized Polypropylene MPP – rated for 440V AC continuous working. That means it must be rated like a Power Factor correction/saving capacitor. It may mean 1KV DC operation.

  • Use an Axial 1uF polypropylene 630V DC or 440V AC Capacitor
  • Sell it with a Marketing Advantage as Power Factor Compensation.
  • Use two 2.2uF 630V DC Axial MPP, one on Live and the other on Neutral.

A house using Motors and Fans will have inductive elements, even tubelights that have chokes 50/60 Hz kind. This is compensated by capacitive loads. So each of these Capacitor LED lamps can be a Green Lighting and PF compensator.