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BUILD LOTTO Do you have trouble filling out your Lotto or Pools coupons every week? Unless you 're a New Age freak, you need a device to select the numbers in a completely random way. Our new Lotto Selector does it properly and will play the new Lotto 44 format. Design by MALCOLM YOUNG Do you try your luck every week? If you do, you'll probably want to try a completely different combination of numbers every time rather than sticking with a few tired old combinations that probably never come up. And if you are playing "Systems" games you want to pick as random a selection of numbers as you can. There's not much point in picking numbers which are not random. By using our new Lotto Selector, you don't have to think abm,1.t picking the numbers. Just push the "Select" button on the side of the Lotto Selector and lights will start to ripple across the LED display. First one LED, then two, then three and so on until a pattern of six LEDs has developed. Then the LEDs will stop and there will be your selection of six numbers. Fill out the numbers and press the button to play again. After you ' ve finished selecting the numbers for this week's game, there's no need to worry about turning the Lotto Selector off in order to save the batteries. The Lotto Selector has its own "power down" circuit which comes into operation about one minute after the last play. When it is powered down, its battery current drain is negligible, at only a small fraction of a microamp! Playing systems games Our new Lotto Selector lets you. play Systems games easily. Want to THIS ELECTRONIC t/POOLS SELECTOR play a 'System 8' game? Simple, rotate the System Select knob to 8 and then push the Select button. The unit will then go through the process of selecting 8 numbers instead of 6. Or perhaps you want to go Lotto in a big way and play a System 12 game. Simple. Rotate the System Select button to 12 and hit the Select button. After building up a random pattern of 12 rapidly moving LEDs, the Lotto Selector will stop and there will be your selection of 12 random numbers. Lotto 40 and 44 Naturally, our Lotto Selector lets you play the newly announced Lotto 44 games in New South Wales as well as the standard Lotto 40 system that will probably be current for some time in other states and in New Zealand. You can play "6 from 36" Pools too. To select which game you wish to play, Lotto 44 or 40 or Pools, just push the Game Select slide switch to the desired setting and away you go. If you don't personally try yout luck every week, the Lotto Selector would make a very nice novelty gift for one of your friends or relatives. Presentation As you can see from the photos, the Lotto Selector is housed in neat plastic case and it has two rows of numbered LEDs running right The Pools/Lotto Selector is built on two PC boards which are stacked together and attached to the lid of the case. External wiring has been kept to a minimum by mounting the two main switches on the PCBs. across the top. For Lotto 44 games, all 44 LEDs are involved in the number selection. In Lotto 40, only 40 LEDs are involved and for Pools, only 36. Even though a total of 44 LEDs is involved, the battery usage of the circuit is quite modest, helped by the fact that only a limited number of LEDs is alight at any time, plus the auto power down feature which means that the circuit only stays on for the time you are actually selecting the numbers. Circuitry In these days of whizbang micro- processor circuitry, you might expect that the Lotto Selector would be based on a one-chip micro and no doubt it would be possible to design a circuit along those lines. But no, our cunning circuit is based on cheap and readily available CMOS ICs which can be purchased over the counter virtually anywhere. However, while the parts may be as cheap as dirt and available anywhere, the circuit is cunning to the point of downright devilment. It contains such features as a pseudo random binary sequence generator (what a mouthful!), a 10 micro- PARTS LIST 1 plastic case with plastic lid, 159 x 96 x 55mm, (Altronics Cat. H-0151 or equivalentl 1 front panel to suit 1 PC board, code SC08105891, 150 x 72mm 1 PC board , code SC08105892 , 150 x 52mm 1 momentary contact pushbutton switch 1 1-pole 12-position PCmounting rotary switch (Jaycar Cat. SR-1 21 0 or equivalent) 1 4-pole 3-position slide switch (made by Taiwan Alpha) 1 12mm knob with pointer, to suit rotary switch 1 4-way AA cell holder (DSE Cat. P6114 , Jaycar Cat. PH-9204 or equivalent) 1 battery snap connector 4 alkaline 1.5V AA cells 14 PC pins 2 1 5mm tapped spacers (Altronics Cat. H-13931 4 1 0mm tapped spacers (DSE Cat. H1832 , Altronics Cat H-1390) 9 3mm x 9mm-long machine screws 1 3mm x 22mm-long machine screw 4 3mm washers Semiconductors 9 4015B dual 4-bit shift registers (IC1, IC6, IC?, IC8-IC13) 1 4093B quad 2-input NANO Schmitt gate (IC2) 1 4030B quad exclusive OR gate (IC3) 2 4001 B quad 2-input NOR gate (IC4 , IC5) 1 1 N914, 1 N4 148 silicon diode (D1) 1 1 N4002 silicon diode (D2) 44 5mm red LEDs Capacitors 1 1 00µF 16VW PC electrolytic 1 1 0µF 16VW low leakage electrolytic 1 .018µF metallised polyester 1 .012µF metallised polyester 1 4 7pF ceramic Resistors (¼W, 5 %) 1 6.8M0 1 1 MO 2 330k0 50 2 1 00k0 4 4 1k0 SILICON CHIP second monostable, an RS latch, free-running oscillators, a 12-bit counter, a 44-bit shift register and the power down circuit already mentioned. Well, all that sounds pretty complicated and so it is but as with any complex circuit, it is made up of a lot of circuit sections which are in themselves fairly simple. Now let's have a look at the circuit. You'll see that certain sections are labelled with the circuit types we have just mentioned. At the top lefthand corner is the pseudo random binary sequence generator (PRBS). This is partly responsible for the randomness of the selected numbers. Next to the PRBS is the lOµs monostable and then r.omes the RS latch. At the top is the 12-bit counter while along the bottom is the 44-bit register. Hi:wing identified some of the major sections of the circuit, let us now get down to some of the detail of how it works. Let's look at the PRBS. The PRBS The term "psuedo random binary sequence generator" needs explaining. A binary sequence generator is a circuit that produces a long sequence of binary numbers. If the sequence is reasonably long, you can regard part of it as a sequence of "random" binary numbers. However, since the sequence of numbers is not infinitely long, it inevitably repeats itself which is why we ref er to it as ''pseudo random". All pseudo random generators are based on a shift register which has feedback applied around it so that that number fed in at the input is constantly changing. Our PRBS is based on a 4015 8-bit register, ICl. Feedback around ICl is applied by exclusive-OR gates IC3a, 3b, 3c and 3d (4030), together with NAND gate IC2a. The feedback circuit takes the binary values at pins 2, 4, 5, 10 and 13 and generates new numbers to be fed into the D-input at pin 7. The new values are constantly shifted through the register with each positive-going clock transition at pins 1 and 9. The clock signal is generated by IC2b, a 2-input NAND Schmitt trigger gate which is connected as an oscillator running at about 27Hz. The binary sequence generated by ICl is 256 bits long. A bigger shift register would naturally generate a much longer sequence but 256 bits is long enough for this circuit. The pseudo random output from pin 3 of ICl is fed to a monostable pulse generator comprising IC4c and IC4d which are 2-input NOR gates. This circuit generates a 10 microsecond pulse for every negative-going transition of the signal at pin 3 of ICl. 44-bit display register Now let's go to the other end of the circuit, as it were, and have a look at the display register. This is the part of the circuit which causes the LEDs to move along and then finally stop after the requisite numbers have been selected. It involves 11 4-bit shift registers, contained in ICs 8 to 13. Actually, ICB to IC13 contain 12 4-bit registers but only 11 are required, for Lotto 44. For Lotto 40 only 10 4-bit registers are required while for Pools, only 9 registers are needed. The number of registers connected into circuit is determined by the setting of the 3-position slide switch S3. !Cs 8 to 13 are connected together in daisy-chain fashion so that the last bit of each 4-bit register connects to the D-input (D stands for data) of the next register. For example, the last bit of the 4th register, pin 2 of IC9, connects to pin 7 of IC10. And :he 4th bit of the last register, pin 10 of IC13, "wraps around" to the Data input of the first register, pin 7 of ICB, via IC5c Fig.1: the circuit of the Lotto Selector ► depends heavily on 4015 shift registers. All the LEDs are driven by a 44-bit shift register which has ls entered into it from the pseudo random binary sequence generator via the latch. The number of LEDs alight is monitored by the counter consisting of IC6 and IC7. IC2d provides the power down feature. t11 .... co Cl:) co > -< ..... ~ .,. OA =27Hz 1M CKA CKB IC1 4015 03 13 71 8 .,. IC6 4015 10 15 04 0 COUNTER DA CKA CKB 1 161 +6V RA 6 RB 14 12 1 2 06 07 08 15 08 CKB CKA 1 9 RB 14 01 15 330k l 100k RA 6 7 DA 0.18! ""60Hz 8 .,. IC7 4015 13 12 11 2 05 06 07 08 +6V IC8 4015 6 RA 14 9 RB CKA IC9 4015 RA 14 1 9 RB CKA CKB T 03 04 DB 05 06 07 08 3 10 15 13 12 11 2 16 POOLS/LOTTO SELECTOR .,. 03 04 DB 05 06 07 08 3 10 15 13 12 11 2 16 7 6 RA 14 9 RB CKA 44-BIT STATIC SHIFT REGISTER T ~ IC10 4015 DA B05060708 01 02 03 04 5 4 3 10 15 13 12 11 2 16 .,. 16 ~K IC11 4015 6 RA 12 11 2 14 9 RB CKA I I .,. Is 01 1N914 +6V AUTO POWER DOWN 100k ·-,- ~ .6.8M 16VW+ 10 100 .J: 16VWJ ON/SELECT S2 14 13 16 14 9 RB CKA 110 113 112 111 IC12 4015 6 RA 12 .,. .,. I Is 14 13 IC13 4015 .,. 110 T l1s =! -I... 6V : 16 14 6 9 1 RB RA CKA CKB 7 -- 8 ...------:lf---r----...--4.---+6V .--------------+-------------➔-------------~~------------- 0.12+ 7•oA +6V +6V PSEUDO RANDOM BINARY SEQUENCE GENERATOR ed into the 44-bit register. Ultimately, the counter will be incremented 6 times and its output at pin 5 (IC7) will go high. This will cut off IC5a and the 6-LED pattern being circulated around the display register will stop. However, this business of loading ls into the display register is not as simple as that. The circuit is arranged so that a "1" can only be loaded if no '' 1'' is already at the input, as fed back from the output. This is accomplished by NOR gate IC5c. If its pin 9 is high, as would happen if the pin 10 output or IC13 is high, then no signal from the RS flipflop gets through. Power-down The two hoards should he connected together and their operation checked before they are assembled onto the lid of the case. The display hoard can he checked separately, as described in the text. and IC5b. These two NOR gates invert the signal twice so that, in effect, the shift register's output is connected directly to the input. All the clock inputs of these register ICs, pins 1 and 9, are connected to pin 3 of IC5a. All the reset inputs, pins 6 and 14, are connected to the anode of Dl. Each register output drives a LED via a lkO resistor so that when the respective output is high, the LED is alight. Therefore there are 44 LEDs which is the number required for Lotto 44. Now what the circuit has to do is build up a random pattern of 6 or more LEDs which is then circulated around the 44-bit register. So six or more "ls" have to be loaded into the display register and the circuit has to count these 1s in order t0 know when to stop the display register circulating. The way in which it does this is quite tricky. 2nd oscillator An extra degree of randomness is provided by the second oscillator, IC2c. This is similar to IC2b but runs at about twice the speed, at 60Hz. The interaction of the 60Hz 52 SILICON CHIP signal from IC2c with the lOµs signal from the monostable (IC4c and 4d) determines how the clock signal is fed to the display register via IC5a (which normally passes signals straight through). Note that as well as providing the clock signal to the 44-bit register, IC5a also drives the RS flipflop consisting of NOR gates IC4b and 4c. The RS flipflop is toggled up and down and its output is fed via IC5c and 5b to the D input of ICB -(the start of the 44-bit display register). Still with us? Good. Note that while one input of the RS flipflop (pin 1 of IC4a) comes from IC5a, the other input, pin 6 of IC4b, comes from the lOµs monostable; ie, pin 11 of IC4d. So the RS flipflop is synchronised to the 60Hz oscillator and occasionally passes a lOµs pulse through, to ultimately become a "1" fed to the 44-bit register. When the RS flipflop lets through a lOµs pulse, the 12-bit counter comprised of IC6 and IC7 is incremented by one. Supposing that the game being played is standard Lotto 44 (ie, 6 from 44 ), the counter will be incremented every time a "1" is load- As noted previously, the circuit has no on-off switch but incorporates an automatic "power down" feature. This makes use of the feature that CMOS ICs use negligible power if their outputs are unloaded and they are not changing state. Therefore the Lotto Selector has the battery permanently connected to all ICs. The power-down feature is provided by IC2d and associated diodes, Dl and D2. When the Select switch S2 is pressed, the lOµF capacitor at pin 12 of IC2d is charged to almost + 6V via diode D2. A line from this capacitor also goes to pin 6 of IC2b and pin 9 of IC2c so these two oscillators can now start running. As well, switch S2 is connected to the reset pins of IC6 and IC7 so that the counter is reset to zero. At the same time, all the reset pins of the 44-bit display register (pins 6 and 14 of ICs 8 to 13) are all taken high via diode Dl. So the act of pushing S2 sets the whole circuit into operation. The voltage on the lOµF capacitor stays high for long enough for the number selection process to go though the whole cycle (even if 12 numbers have to be selected) and then let the LEDs stay illuminated for about one minute. After this time, the voltage across the lOµF capacitor falls to the lower threshold of IC2d and its output at pin 11 then goes high. This output is connected to the reset line for the 44-bit register via a lOOkO resistor. This resets the display + ~ BATTERY S~ ,._,~ Fig.2: the Lotto Selector is built onto two boards, the larger one being the display board carrying the 44-bit register. The other board carries the remaining circuitry. After assembly and checking the two hoards are stacked together on the case lid. 0 CAPACITORS □ □ □ Value 0 .18µF 0.12µF 47pF IEC 180n 120n 47p f.lA 184K 124K 47K RESISTORS □ □ □ □ □ 1 1 2 2 44 Value 6.8Mf2 1 MO 330kf2 1 OOkfl 1 kO 4-Band Code blue grey green gold brown black green gold orange orange yellow gold brown black yellow gold brown black red gold register so that all its outputs go low and all LEDs are extinguished. At the same time the enable line to the two oscillators (pin 6 of IC2b and pin 9 of IC2c) will have gone low and so these two oscillators will stop operating. This means that none of the CMOS stages will be changing state and the quiescent current of the circuit will be extremely low . In fact, the leakage current through the lOOµF bypass capacitor across the battery is likely to be higher than the current drawn by the CMOS ICs. Note that connecting the reset line from pin 11 of IC2d to the 5-Band Code blue grey black yellow brown brown black black yellow brown orange orange black orange brown brown black black orange brown brown black black brown brown display register via a lOOkO resistor is a little odd. The more conventional way of doing it would have been to connect the line direct from pin 11 to the reset pins and then have a lOOkn pull-down resistor to ensure that the reset line was definitely low when it was supposed to be. However, usmg that arrangement would have meant that the lOOkO resistor would have the full supply voltage across it when the reset line was high fas it is in the power down condition). This is undesirable as it results in a fixed current of 60 microamps. So we have connected the resistor as shown to give zero current in the reset condition. Battery options Our circuit is shown powered at 6V from four 1.5V AA cells. When the display is stationary, the current drain varies from about 27 to 55 milliamps, depending on the number of LEDs alight. If you use high brightness LEDs instead of the conventional types we specified, you can change the LED resistors to 2.2kn. This will more than double the battery life. Either way, you should use alkaline cells for best battery life. MAY1989 53 The counter board is attached to the back of the display board and retained by the nut of the rotary switch at the lefthand end and by a long machine screw through the tapped spacer at the righthand end, as shown here. Construction Here the Lotto Selector has been set for a System 10 game in which 10 LEDs are alight. The selected game is Lotto 44 - note the setting of the slide switch. Current drain is proportional to the number of LEDs alight but the circuit powers down after about one minute to conserve the batteries. 54 SILICON CHIP The Lotto Selector circuitry is accommodated on two printed circuit boards. The larger of the two, measuring 150 x 72mm and coded SC08105892, is for the display board. It accommodates the 44 LEDs, their series resistors, and the six 4015 ICs. The other board, which we 'll refer to as the counter board, measures 150 x 52mm (code SC08105891) and takes the rest of the circuitry, including the rotary switch. The first step in construction is to carefully examine both boards for any faults in etching, shorts between tracks or pads and open circuits (breaks) in tracks. This done, identify the + 6V and 0V tracks and check with your multimeter (switched to an ohms range) that these tracks are not shorted. Step 1: insert and solder the PC pins in both boards. A total of 14 pins is required and as they are a tight fit you'll need a small hammer . to put them in. You can also install the tinned copper wire links at this stage. One of the links on the counter board follows a circuitous route so it needs to be made of insulated hookup wire. Step 2: insert and solder the resistors on both boards. We have listed all the resistor values and their colour codes below the board wiring diagrams. The idea is to do all the resistors of one value first , starting from the top and working down. As you install all the resistors of each value, tick the square box. Be sure to install the resistors so that their colour codes all run in the same direction across the boards or down the boards. This makes it much easier to check that all resistors are of the correct value. Step 3: insert and solder the two diodes and the five capacitors. Dl is a small signal diode, type 1N914 or 1N4148. Make sure the band at one end matches that on the diagram. D2 is a larger diode (because it has to pass the brief but heavy charging current for the 10µ,F capacitor) and it should be installed so that its cathode band is closest to IC1. The 100µ,F capacitor is mounted on the display board. Make sure its polarity is correct. The same goes for the 101-tF electrolytic on the other board. The three other capacitors are listed next to the wiring diagram, together with their alternative markings in the IEC and EIA codes. Step 4: install and solder the integrated circuits. Make sure that pin 1 of each IC (near the dimple or notch in the IC package) corresponds to the same orientation as shown on the wiring diagram (Fig.2). We soldered all ICs directly into circuit but there is nothing to stop you from fitting IC sockets they do make it delightfully easy to change an IC if you have to do so. Step 5: fit and solder the LEDs. They should all be soldered so that they stand up above the display board by the same amount. One way to do this is to insert all the LEDs into the board and bend the leads slightly so that they don't fall out again. This done, place two ~ = 0 ~ (.) UJ ....I UJ (I) 0 ~ ~ 0 ....I + N+ ~ + ~ + ~ + ~+;+ ~+~+ ~+~+ ~+~+ + ~+ ~ + ~+~+ Lt)+ ,.... r,... (t) N+o:::t+ ,.... (t) ;::+ ~+ ~+~+ o,+c::;+ ~ + + (1) r,... + re + 0 0 CD+~+ Lt)+~+ o:::t + ~ + M+ CL. L 7 ~ + 00 ---....I (l)W..JW(.)1- Nt .....+ :::Et- W(.) 1-W Cl) ..J >W (/)"' .• + (\I ,... ,... 0,.... ,... a>e a:,• •• r-- <0 _J Fig.3: here is an actual size artwork for the front panel. pieces of 15mm-thick timber on your workbench to act as board supports. Place the board on these timber supports so that the LEDs fall through and are supported on the bench surface. Solder the LEDs and then check to see that they are all in line and at the same level. Step 6: insert and solder the switches. Slider switch S3 , on the display board, is easy enough to fit , as it will only go in one way. The same applies to the rotary switch S1, on the counter board. However, before fitting the rotary switch you should set it so that it only provides 6 .positions. You can do this by removing the fixing nut and washer and lifting out the indexing ring and then repositioning so that the tab goes in hole 6. The switch should now provide 6 positions. The shaft of the switch should be cut to about 17mm long. Do this before you solder the switch onto the board. When inserting the rotary switch into the counter board do not force it. If the PC holes are not quite big enough, they should be drilled out to the right size (1/16in or 1.5mm). If you try to force these switches in and then solder them, they can be unreliable. Step 7: carefully inspect your MAY1989 55 The final step in the assembly is to stack the two printed hoards together on the lid of the case. Fig.4: above are the actual size artworks for the two printed hoards. 56 SILICON CHIP work and compare the completed boards against the wiring diagram [Fig.2). Do not interconnect the boards at this stage. Preparing the case Use the self-adhesive label as a drilling template for the case lid. Don't fix it to the lid at this stage; just line it up on the lid and use a spike to push through it and mark the centre points for the holes. Take care that all the LED holes line up because this will have a big effect on the overall appearance. Don't drill the holes oversize. If you are using 5mm LEDs, the hole size for a snug fit is about 4.5mm. We suggest you use a 4mm or 11/64-inch drill and then use a tapered reamer or rat-tail file to enlarge the holes to the correct size. You can check the fit of the LEDs in the lid by using the counter board assembly. Do the LEDs all line up nicely? Good. If not, now is the time to make adjustments. Use the counter board as a template for its four mounting holes on the lid. You will also need to drill a hole in the case for the Select pushbutton, SZ. Step 8: fix the label to the lid of the case. Future kits may come with the lid already silk screened so this step may not be necessary. Step 9: check the operation of the counter board. To do this you need to connect the plus ( + ) and minus ( - ) lines to the battery or to a power supply of between 3 and 9V DC. Then there are the Data in and Data out, Reset and Clock lines to manipulate. Connect the Reset line [the arrow marked '3' near ICl 1 on the display board diagram) low for normal operation. Connect it high to extinguish all LEDs. Connect the Data line (the arrow marked '5' near ICB on the display board diagram) high (ie, the + 6V line) to feed 1 's in. You can then clock them along manually by taking the clock line [the arrow marked '4' on the display board) alternately high and low. Check that the Game Select slid·e switch works correctly. In the Lotto 40 mode, LEDs 41 to 44 should never light. In the Pools mode, LEDs 37 to 44 should never light. The Pools/Lotto Selector is powered by four AA cells housed in a snap-in holder. The holder can he retained using double-sided tape. To start the Lotto Selector running, you just push the Select button on the end of the case. A random pattern of LEDs then starts to build up one by one as they move across the display. The unit turns off automatically. Check that taking the Reset line high extinguishes the LEDs. Tha t done and the display board can be pronounced a goer. Step 10: interconnect the two boards and check that the whole circuit operates as it should. If you find problems, remember that the most common problem with a circuit of this sort is solder shorts between tracks or IC pads. Carefully examine the boards for these faults and for missed or poor solder joints. Step '11: mount the two boards on the lid of the case. The counter board first has to be attached to the display board. Attach two 15mm tapped spacers to the counter board. The spacer nearest the rotary switch is retained with a 9mm machine screw while the other is retained with a 22mm screw. The counter board is then attached to the display board. At one end it is retained by the nut on the rotary switch. At the other end it is retained by a 10mm tapped spacer over the 22mm machine screw. That done, you need to fit three more tapped 10mm spacers to the display board. The whole assembly can then be fitted to the lid of the case and retained with four 9mmlong screws. Step 12: fit pushbutton SZ and the battery holder to the case. Connect the battery snap and you are in business. Now you can go Lotto as often you want. ~ MAY l9RQ 57