The SMD Training PCB - RAN 004/03 - Playing the Game 4 Dec 2004 Reading binary quickly and accurately is a useful skill for an electronics engineer - whether designing or repairing. Usually you might be called upon to read binary off DipSwitches, or off a data or address bus. Normally the binary number would be converted to Hexadecimal (Values 0-F) or decimal (0-15) to make sense of the value. When completed, the SMD Training PCB plays a game that helps learning Binary. The SMD Training PCB can be powered off any voltage between 7.5 and 15VDC, and draws a current of less than 100 milliamps. Ideally the board was intended to be driven by 12VDC. It should be pointed out that most of the cheaper DC wall adaptors are unregulated, and the best wall adaptor for powering this board is probably a "9V" marked unit, which is likely to put out closer to 12V at the low 100ma load. The power supply should be connected with Negative to the "Gnd" marked position of CN1 Power, and the positive to the "+12" marked position of CN1 power. Do not connect to the "+5" position of CN1 power, which is actually the onboard regulated +5V rail. Upon connecting to power, the game "rolls a new number" - with LEDs L1-L4 lighting as they cycle through all possibilities. The roll stops on one value, indicated in binary on LEDs L1-L4, labelled Bit0, Bit1, Bit2, Bit3. The object of the game is to quickly associate the 4 bit value displayed on LEDs L1-L4 with a number from 0-15 (Decimal) or 0-F (Hexadecimal), and touch the corresponding testpad T0-T15 with the Probe. If you select the correct answer, the green LEDs (L6-L7) will flash for as long as you touch the probe to the answer. If you select an incorrect answer, the red LED (L5) will light. After releasing the probe, the game "rolls a new number". If you find that your board is showing you predictable values, and does not seem to be random, it is likely that the oscillator formed by R18-C8 is too well matched to the time constant formed by R17-C6. The results can be made to seem more random by altering C8 (100nf) to another value (eg 1nf). A Binary values chart: L4 L3 L2 L1 Binary Decimal Hexadecimal - - - - 0000 0 0 - - - ON 0001 1 1 - - ON - 0010 2 2 - - ON ON 0011 3 3 - ON - - 0100 4 4 - ON - ON 0101 5 5 - ON ON - 0110 6 6 - ON ON ON 0111 7 7 ON - - - 1000 8 8 ON - - ON 1001 9 9 ON - ON - 1010 10 A ON - ON ON 1011 11 B ON ON - - 1100 12 C ON ON - ON 1101 13 D ON ON ON - 1110 14 E ON ON ON ON 1111 15 F My name is Steven Murray from AirBorn Electronics, thankyou very much for taking the time to read this documentation. I enjoyed designing this board, and I hope that you also find it enjoyable putting it together - visit our website if you like: http://www.airborn.com.au ...or better still: http://www.airborn.com.au/client/navy/smdtrain.html