Hobby Projects - Insulation tester, LED Circuits, Meters.
Showing posts with label Schoodles-3. Show all posts
Showing posts with label Schoodles-3. Show all posts

Thursday, July 19, 2012

Reuse Wireless Keyboard and Mouse

Many people give up on Wireless Keyboard Mouse Combo after a few months of "Novelty". This is due to the chore of replacing batteries and also the cost and wastage (carbon foot).

Then i have long been suggesting, nineties, ferrite smps coupled charger docks. This is like RFID, but more like RF power transfer. One half of Ferrite E-Core is in the Gadget and the other half is in the Dock. When the Gadget is docked it is sensed and power transfer just like in SMPS. Rechargeable batteries in the gadget.

Here is the Schoodle for building this. The Mumbo Jumbo to make a Wired-Wireless Combo

Reuse Wireless Keyboard and Mouse

How-To Convert Wireless to Pseudo-Wired 

Now you got a Wireless Combo, it can be converted into wired yet wireless, it is simple the wires will now carry 3V power to the Keyboard and Mouse, so no batteries. A little gentle and smart drilling is needed for the Mouse.

Get a 5V Adapter, the ones used for charging phones and music players. If you cannot get 5V use a 7805 to derive a 5V from 6 or 9. Use two 1N4007 in series on the positive line to drop 1.5V - test out with a dummy load of 10K and 100uF cap. Now use this to power both the mouse and keyboard with thin dual-core wires leading to the battery terminals. Soldering this may be a delicate job. Now you got a Perpetual Wired Keyboard Mouse Combo. The Interface still remains Wireless.

Another way is use Rechargeable Batteries for both. The wires will carry exactly a regulated 3.3V from a LM317 circuit which can be tweaked. The Mains adapter can be any 6V or 9V raw DC. You can have a Connector for the power wires when you want it to be wire free. This may require greater Gadget Opening and Drilling Expertise.

Reuse - Be Earth Friendly - Keep your Carbon Footprint smaller than that of a Yeti.

Saturday, November 06, 2010

LED Lamp – Simple Bed-Lamp Circuit

LED Night lamp, Clock Lamp to see time at night. It is a Green Lamp just 50mA, but its Blue in Color.

LED Lamp – Simple Bed-Lamp Circuit

This can be a first LED Lighting project anybody can do. Just twist wire, use insulation tape. Get a Nice Mains adapter that will provide 6V DC. 5V also will do. A prior Knowledge of Ohm's law is essential.

Monday, November 01, 2010

LED Flashlight made out of a China Lamp

LED Flashlight made out of a China Lamp that was busted on a High voltage surge during a Thunderstorm.

LED Torch or Flashlight

I got many LED lamps, mainly from china. The Chinese Entrepreneurs are Creative and Adventurous. There is a problem though, the quality, reliability and safety factors are not so good. These are so for even branded china products. That is offset by a affordable price.

LED Flashlight made out of a China Lamp

Then China is going thru the learning curve like Korea and Tawian. Now Taiwan makes world class products.

Wednesday, October 20, 2010

LED Lamp or Bulb with Flashlight option

This is another LED lamp from China, 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.

LED Lamp or Bulb with Flashlight option

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.

Monday, July 12, 2010

One Watt Mains LED Lamp or Tubelight

Lots if Light on One Watt, yes this works, but should be built by those experienced in High Voltage usage and Knowledge of insulation techniques.

This has to be encapsulated in a insulated fire retardant plastic enclosure. You can change the values around what is indicated to experiment with types of White LED available.

One Watt Mains LED Lamp or Tubelight

This project is not for Youngsters or those who are still learning. High Voltage can cause injury and can be fatal too, when used or applied without experience, training or supervision.