PRACTICAL ELECTRONICS MASTERCLASS (Mr Bell)

What are Batteries? A battery contains electro chemical cells in which chemical reactions create an electrical potential current between the positive and negative terminals. They where invented by Alessandro Volta (where the unit Volt comes from) in 1800. The longer of the two lines represents the positive (+) side of the battery. The first diagram indicates a singe battery of less than 3V. The second diagram indicates multiple batteries connected. The third diagram indicates a battery of greater than 3V is getting used.

Different types of Batteries. Two types:- Primary batteries (disposable) which are used once and discarded (cheaper). Secondary batteries (rechargeable) which are designed to be recharged and used multiple times (more expensive). Batteries range in size from button cells to large-acid units that store power generated by solar panels or windmills. Letters indicate the batteries size (AA 24mm x 14.5 diameter)

Glue and solder battery holder Insert wires through holes first before gluing

- + + -

How it works The wand detects when you start moving it across the sky. As you start the sequence, the LED’s flicker in pattern quickly to produce the letters in sequence. Because your eyes cannot see accurately it appears as though it is writing letters across the sky. This technique is called: PERSISTENCE OF VISION (POV)

Programming Instructions First familiarise yourself with the buttons and switches

Now practice setting your own words and the waving technique, enjoy. To enter programming mode tilt the wand to the right and wait until the LED’s are stationary, then press the set button. The green LED will come on to indicate you are in programming mode. Use the + and – push buttons to move up and down the different LED combinations (binary form), which represent different letters from the table on the next slide. When you have found the letter you want, push the set button and the LED’s will confirm this by flashing. You must enter 6 characters, if not 6 then you can enter spaces to make it up to 6. Once all 6 are put in it will flash briefly and come out of programming mode and start flashing your letters. NOTE: the microchip is not reprogrammable so when you switch it off it will go back to the default “Rapid” word. Now practice setting your own words and the waving technique, enjoy.

Binary code reference table