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Builld the E,cecutive Thingie Exaoutiva Ihiugia Many executives often suffer from a complaint commonly referred to as "executive stress". If that fits you, then you need the fast-acting relief of the Executive Thingie! You simply tilt the box in any direction to produce four different and medicinal musical notes. How many times have you walked into the boss 's office to find him slowly sliding under the desk with his eyes spinning in a counter-clockwise fashion? Believe it or not, this is a definite case of "executive stress", the management version of "industrial disease". The question is, what can be done about it? We believe that the solution is as simple as a few ICs and a soldering iron: get · him (or her) to build the Executive Thingie. When tilted, this ingenious device closes one or more mercury switches, thus triggering a tone to calm those jangled nerves (or make them worse)! Apart from that, the device is completely useless although you may learn By DARREN YATES 30 SILICON CHIP a few things while building it. The unit runs off a 9V battery and uses easy-to-obtain parts. Indeed, by the time you have it up and running, your worries may be over! Block diagram Fig.1 shows the block diagram of the circuit. As can be seen, it uses four tone generators and these are made using a single 4093 quad Schmitt trigger NAND gate IC. Each generator output feeds one of four voltage-controlled resistive volume controls. These controls are based on the FETs found inside a couple of 4007 !;lual complementary pair ICs and are activated by mercury switches MS1-MS4. The output from each volume control is then resistively mixed with the others and fed to an audio output stage. In practice, the mercury switches are split into pairs, with one pair used to monitor the x-axis and the other used to monitor the y-axis. When the device is held perfectly level, all switches are open and all the voltage controlled resistors have a very high resistance. Thus, no tones are fed through to the loudspeaker. However, when the device is tilted, one or more of the mercury switches will close and their corresponding voltage controlled resistors will switch to low resistance. These in turn allow signals to pass from their corresponding tone generator stages to the amplifier stage. +gv---i--1--1------.! MS2 MS1 MS4 MS3 JQIIE. OSCILLATOR 1 TONE OSCILLATOR 2 TONE OSCILLATOR TONE OSCILLATOR 3 4 VOLTAGE CO~T.!ll!!J.!;I) RESISTOR DIVIDER 1 VOLTAGE CONTROLLED RESISTOR DiVIDER 2 VOLTAGE CONTR.OLLED RESISTOR DIVIDER 3 R ij R Circuit diagram OUTPUT DRIVER Fig.2 shows the complete circuit details. It's easy to identify the various circuit sections. ICla, IClb, IClc & ICld are the tone oscillator stages, while IC2a, IC2b, IC3a & IC3b are the voltage controlled resistors. Ql, Q2 and their associated components form the output driver stage. Note that the four combined tone oscillator/voltage controlled resistor stages are identical. To simplify the description, we'll just concentrate on SPEAKER Fig.I: the Executive Thingie consists of four identical stages which are activated by mercury switches (MS1-MS4). The various outputs are then mixed & fed to an audio amplifier stage. the stage based on ICla and IC2a, since the other three stages all function in exactly the same manner. NAND gate ICla is connected as a square wave oscillator. Its output frequency is set by the lOOkQ trimpot S1 <>--;]_ 100 + 16VWJ T, B1 MS1 9V MS4 ~ i VR1 100k 10k .022! 322! .022! 10 2.2 + 25VWr 10 + 390k 390k .,. .,. 10k 10k 10k 2.2 2.2 390k 25VWr .,. -:- 25VWJ_ 390k 10k 10k -:- ':' .,. ,--------•9V Ic2 1Ic3 100 16VW E ·1n B ELJc VIEWED FROM BELOW Bll SPEAKER 02 BC327 C .,. EXECUTIVE THINGIE .,. Fig.2: the four oscillator stages are based on a 4093 quad NANO gate IC (ICl). IC2a, IC2b, IC3a & IC3b function as the voltage controlled resistor stages while Qt & Q2 form the basis of the audio amplifier. APRIL 1992 31 The assembled PC board is mounted on the lid of the case using screws, nuts & shakeproof washers, while the loudspeaker is fixed in position using contact adhesive. Use a small piece of foam rubber to wedge the battery in position when the lid is attached. and the .022µF capacitor on pins 1 & 2. The resulting output signal appears at pin 3 and is fed via a 10kQ resistor to pin 5 of ICZa. ICZa is a FET (field effect transistor) and is part of a 4007 complementary pair IC (ICZb is the other transistor in the package). Its gate is controlled by mercury switch MS1, a 390kQ resistor and a 2.ZµF capacitor. When the mercury switch is open, the voltage across the 2.2µF capacitor is zero and so the FET is turned off. This means that the FET presents a very high resistance between pins 5 & 4 of ICZa and so no signal appears across the 10kQ resistor on pin 4. Conversely, when the mercury switch is closed, pin 3 of ICZa is connected to the positive supply rail and the FET turns on. The FET now has negligible resistance, which means that the two 10kQ resistors connected to pins 4 & 5 now act as a simple voltage divider for the tone oscillator signal. Chime effect The chiming effect is created when the mercury switch opens again. Initially, the 2.ZµF capacitor is charged to the full supply voltage (9V) and so, when the switch opens again, the FET is held on by the voltage across the capacitor. The parallel 390kQ bleeder resistor - This close-up view shows how the mercury switches are installed. Bend their leads at right angles about 2mm away from the glass bodies before mounting them & make sure that they are parallel with the edges of the board. 32 SILICON CHIP now discharges the 2.ZµF capacitor. As the voltage across this capacitor decreases, the FET resistance gradually increases, thus giving us a decaying signal amplitude on pin 4 ofICZa. The result is that the tone volume decreases to nothing over a period of about one second. This sequence of events occurs for each of the four sections of the circuit, depending on which way you tilt the case to activate the mercury switches. The output signals from each section are then mixed together via four 10kQ resistors and coupled to the audio output stage via a 0. lµF capacitor. Transistors Ql & QZ form a simple complementary class AB audio amplifier and this drives an 8Q loudspeaker via a 100µF capacitor. The two diodes, Dl & DZ, provide about Mount the mercury switches so that the ends with the leads sit slightly proud of the PC board. This is necessary to ensure that all the mercury switch contacts are open when the project is placed on a level surface. PARTS LIST =l uF Fig.3: install the parts on the PC board as shown in this layout diagram. Take care with component orientation & make sure that you don't transpose Q1 & Q2. The four trimpots (VR1-VR4) allow the tone frequencies to he adjusted. 1.2V of bias between the bases of the two transistors to reduce crossover distortion. Without the diodes, each transistor would be off for the first 0.6V swing of its half-cycle. Power for the circuit is derived from a 9V battery via switch S1. The current consumed is approximately 0.9mA with no tone and about 9mA with tone. Construction All of the components except for the loudspeaker, power switch and 9V battery are mounted on a small PC board coded SC08103921. Fig.3 shows the assembly details. When you first buy or make the board, check it thoroughly for any shorts or breaks in the tracks. If you find any, use an artwork knife or a dab of solder where appropriate to fix the problem. It's far easier td do this now rather than to track down faults after the board has been assembled. Begin the assembly by installing the wire links. It's important to keep these as straight as possible so that they don't short out any other components (you can straighten the link wire by clamping one end in a vyce and then stretching it slightly using a pair of pliers). Next, install the resistors and the four trimpots. If you are unsure about the resistor colour codes, check them using a digital multimeter or refer to Table 1. The two signal diodes are the next to go in, followed by the capacitors and the two output transistors (Q1 & Q2). Check the polarity of the diodes and transistors carefully and make sure that you don't transpose Ql and Q2 (one is an NPN type and the other is a PNP). Similarly, make sure that you install the electrolytic capacitors the right way around. Now for the three ICs. These are installed in the centre of the board and all face in the same direction. Be careful not to overheat the ICs and make sure that there are no solder bridges between adjacent pins. Finally, solder in the four mercury switches. These must all be installed so that the end with the leads sits up higher off the board than the other end. This is necessary to ensure that the project must be deliberately tilted in order to generate a sound output. As a guide, if you sit the board down on a flat table, the mercury should run away from the contact pins in each case. By the way, don't play with the mercury if you inadvertently break any of the glass envelopes. It's highly poisonous. Now that you have finished the board, check it carefully for solder splashes, shorts between tracks and 1 PC board, code SC08103921 , 106 x 58mm 1 plastic zippy box, 130 x 68 x 41mm 4 mercury switches (MS1 -MS4) 1 Dynamark front panel label 1 9V battery snap connector 1 9V battery 1 SPST toggle switch (S1) 1 8-ohm 57mm-dia. speaker 4 1 00kQ horizontal mount trimpots Semiconductors 1 4093 Schmitt trigger NAND gate IC (IC1) 2 4007 dual complementary pair/ inverter IC (IC2,3) 1 BC337 NPN transistor (01) 1 BC327 PNP transistor (02) 2 1 N914 diodes (D1 ,D2) Capacitors 2 100µ,F 16VW electrolytics 4 2.2µ,F 25VW electrolytics 1 0.1 µF 63VW MKT 4 .022µF 63VW MKT Resistors (0.5W, 1%) 4 390kQ 233kQ 12 10kQ Miscellaneous Screws, nuts, solder, hookup wire, tinned copper wire for links missed solder joints. Check also that all the components are in their correct locations and are correctly oriented. Testing When these checks are complete, you can connect the loudspeaker and battery to check that the circuit works correctly. Initially, it's a good idea to connect your multimeter (set to a milliamp range) in series with your power supply. If the current drain TABLE 1: RESISTORS I a a a a No. Value 4-Band Code (1%) 5-Band Code (1%) 4 2 12 3901(Q 33kQ 10kQ orange white yellow brown orange orange orange brown brown black orange brown orange white black orange brown orange orange black red brown brown black black red brown APRIL 1992 33 ...... - I ' ARGON LASER These cooled Argon Laser • .•. -_ .f Heads air have had relatively _ "low hours" of operation. They are guaranteed. They · produce a bright blue beam :. (488nM) and have a power ·· output in the 10-100mW range. Limited supplies, at a small fraction of their real value. The head includes power meter circuitry and · - ·• _ ' t. " ONLY saoo ~l~~i;~o~\dc~~,~~- ;ti~~~t/~i?~a~:;r;ig~~er supply. We can provide the major components for this supply. Enquire. I, I.R. BINOCULAR VIEWER Fig.4: this full-size artwork can be used as a drilling template for the front panel. Drill small pilot holes first, then carefully enlarge them using a reamer. Suit teachers, doctors, businessmen, and other professionals. Improve and enhance all your presentations. Not a kit, but a complete commercial pen sized laser pointer at ONLY ~~r~ndc~~~~~eprice~199 Small pen sized body. Runs on two small AAA battery. Battery life: 2-10 hours. Visible 5mW red (670nM) laser. Projects a visible red spot at more than 50 metres. As used for medical treatment by doctors and acupuncturists. Small black anodised metal body. Removable pressure switch . Vertical and horizontal adjustments. Battery life more than 10 hours continuous. SmW 670nM class IIIA laser. Range is about 150m, some would claim three times more. Shock tested to 2000g. One year warr'l5'~i.v 5 299 Price includes one rifle or pistol mount 3mW GAS LASER ~~~~7. 1 ~i~~c~ra~ i1Wi Self powered, and originally intended to be mounted on a helmet. Focus is adjustable from 1 metre to infinity. Requires some IA illumination. Powered by one single 1.SV battery. Original , ~~;:g~~~~i~:~_Y Limited stock. 5 649 I VISIBLE LASER • DIODE HEAD · , Save, by making your own laser pointer, laser gun sight, medical treatment laser, etc. Produces a well collimated beam. Designed to be powered directly from a 3V battery, or from higher voltages, if a simple constant squrce is added. Simple circuit included. 5mW (670nM). At an incredible $135 inr\~~d~f'ory ~or the head only: Add $8 for the extra "bits" needed to make a complete laser diode pointer. Case, switch, alkaline batteries, and battery holders. Everything you need to make a complete, self contained, visible laser pointer or gunsight. ~ l Includes high quality low divergence Siemens laser head with an output at about 3mW and one of our reliable and efficient 12V universal laser power supply kits. The tube is used but it is guaranteed. The kit comes with full instructions and it even includes a prewound transformer. The applications include high power laser pointers, surveying equipment, optical experiments, education, holography, medical ~f~~ia~~citc exceeds Z0mA, switch off immediately and locate the source of the problem before proceeding further. If everything is OK so far, try tilting the board in each direction. You should hear four distinct tones. If any of the tones fails to sound, check the circuitry associated with that particular mercury switch. Once you have the circuit working correctly, the four trimpots can be adjusted to produce the desired notes. You do this by tilting the board in one direction to close one of the mercury switches and adjusting the corresponding trimpot until you get the desired tone. Adjust VRl for mercury switch MSl, VRZ for MSZ, VR3 for MS3 and VR4 forMS4. Final assembly The PC board bolts directly to the lid of the specified case using four screws and nuts, with extra nuts used as spacers. Drill these four mounting holes first, using the PC board as a template, then attach the front panel label to the lid and clear the holes using a sharp artwork knife. This done, drill the holes for the loudspeaker and another hole in one end of the case for the power switch. In each case, it's best to drill a small hole first and then enlarge it using a tapered reamer. The loudspeaker can now be glued to the lid (behind its holes) using a suitable adhesive. Wait until the glue dries, then install the PC board and power switch and complete the wiring. The battery sits on the bottom of the case and can be held in position using foam rubber when the lid is attached. Don't forget to switch the unit off when it is not in use, to preserve battery life. All that's left now is to find that frazzled executive. The symptoms shouldn't be too hard to spot. SC As per EA Oct. 91 issue. Very small size! Complete kit includes an objective lens, an infra red image converter tube, an eyepiece, an electronics kit and sufficient plastics for the case. Very simple to construct. ONLi99 ONLY s299 Melbourne Distributor: Electronics World (03) 723 3860 or (03) 723 3094 OATLEY ELECTRONICS PO BOX 89, OATLEY, NSW 2223 Telephone: (02) 579 4985 Fax: (02) 570 7910 Certified p&p: S6 in Aust. NZ (Airmail) : S10 34 SILICON CHIP Fig.5: here is the full-size etching pattern for the PC board.