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Look Mum, no hands (or digits!)… dahdah dahdahdah di’dahdit di’di’dit dahdi’dahdit di’dahdi’dit dahdahdah Here is a novel clock that doesn’t have a readout. It’s a talking clock, but instead of telling you the time in words it sounds the time in Morse code. A maze your friends by being able to tell the time just by listening to some dots and dashes. If you are an amateur radio operator, it is sure to make a great addition to your shack. There have been hundreds of clock projects over the years but to my knowledge there has never been one like this. The clock features hourly chime, one second internal resolution with an announcement resolution of one minute, and you can also select 12 or 24 hour time and set the speed of the Morse! As with a lot of projects that have appeared in SIL­ ICON CHIP this clock uses a mi­ crocontroller – in this case a PIC chip – to do all the work. There are very good rea­ sons for this; PICs are amazingly ver­ satile and they turn what would have once been a complex project into a very simple one. Of course, the fact that we are not worrying about driving a LED or LCD display makes it even easier, with the output device being a small piezo buzzer. Using Morse code also makes the project simpler, just like a Morse code radio transmitter is a lot less compli­ cated than a voice transmitter. With Morse code we just have two states to worry about; either the tone is on and we can hear it, or it is off and we can’t hear it. Now if you haven’t 68  Silicon Chip learnt Morse code yet either through your work or as a hobby, don’t worry. To be able to tell the time with this clock only requires a rudimentary knowledge of the code. Indeed to get you started there is a slow Morse setting so that you can get in some practice before you move onto the fast Morse setting. The project is constructed on a small PC board and housed in a plas­ tic box. Power is normally supplied from a 9V DC plugpack, however the box incorporates a battery backup in case of power failure. The Morse clock has only two buttons, TIME and SET. The TIME button is used to announce the time and also step through the functions in program mode. The SET button is only activated in program mode and is used to select the options for by Leon Williams VK2DOB each of the functions. How to set the time and program the functions is described later on. Circuit description The full circuit is shown in Fig.1. As you can see there is not a lot to it, with the PIC chip (IC1) doing almost all the work. The PIC chip used here is a 16F84 and is very commonly used. Its major advantage is that it can be programmed with a cheap and simple programmer and can be re-programmed over and over. So if you make a mistake with the pro­ gram (it’s an unwritten rule that programs n e v e r work first time), you can simply rewrite the chip with­ out having to throw it away or erase it with UV light. Packed inside the PIC (amongst other things) is a general purpose timer, 13 I/O pins that can be individually configured as outputs or inputs and 1K of flash ROM and 68 bytes of RAM. Pins 15 and 16 of IC1 are the oscil­ lator pins, connected to a 3.2768MHz crystal and two 22pF capacitors. The crystal frequency is divided by four inside the PIC to give an instruction clock of 819.2kHz. This is further di­ dit dahdi’dahdit dahdi’dah* *(MORSE CLOCK) vided by 64 in a pre-scaler and this is applied to the clock input of Timer 0. Timer 0 counts from 255 down to zero, repeating at a rate of 50Hz. The PIC is interrupted each time Timer 0 reaches zero and the software counts these pulses and when 50 are counted, one second has elapsed. The second count is in turn used to increment the minutes and hours counters. Pin 4 is the reset pin and is tied to +5V by a 10kΩ resistor. The PIC has a built in intelligent reset circuit and this should prove to be adequate in this application. However, if the power supply is disconnected, allow enough time for the bypass capacitors to discharge before reconnecting the power, otherwise the reset may not work properly. The TIME button is connected to Pin 7 which is configured as an input to Port B and has an internal pull up resistor. When the button is not pressed the PIC reads the pin as high; when the button is pressed it is read as low. The SET button is connected to pin 8 and acts in the same way. The software performs a debounce operation on the buttons. When a but­ ton is first detected as being closed, it waits for a short period and tests the button again. If the button is still closed, the program accepts this as a valid press otherwise it treats it as a spurious input and ignores it. The remainder of the Port B pins are configured as outputs and so do not need to be tied to a rail. The Port A pins are all configured as outputs with pin 1 used to activate the piezo buzzer. When the output is high (+5V) the buzzer is on and when the output is low (0V) the buzzer is turned off. The timing of the dots, dashes, character and word spacing are all multiples of the interrupt period (20ms). The software simply counts the number of interrupt peri­ ods and holds the output pin high or low for the prescribed period. The clock is powered from a nomi­ nal 9V DC supply, such as a plugpack. Diode D1 provides protection from reverse polarity and the 100µF capaci­ tor helps reduce power supply ripple. Regulator REG1 is a 78L05 type and its output voltage is raised to around 5.5V by D2, with the 0.1µF capacitor guarding against instability. Diode D3 drops this voltage back to 5V to We think old Sam Morse would have approved . . . supply IC1 at pin 14 and also stops the battery current from flowing back into REG1. When the power supply is re­ moved, power for IC1 is supplied by a back up battery supply comprised of 3 AA cells. When normal power is applied from the plug pack, diode D4 is reversed biased and so no current is drawn from the batteries. Howev­ er, when the main plugpack supply is not available, diode D4 conducts because its anode is more positive than its cathode and current for IC1 is supplied by the batteries. The PIC chip draws around 1mA when in idle condition and about Fig.1: the circuit diagram is just a power supply and a PIC microcontroller. December 2000  69 Parts List: Morse Clock 1 PC board, code 06112001, 72 x 56mm 1 plastic case, 130mm x 67mm x 44mm 1 panel mount DC connector to suit plugpack 4 PC board stakes 1 3.2768MHz crystal (XTAL1) 1 piezo buzzer (Jaycar AB-3459) 2 PC-mount push button switches (S1,S2) 1 18-pin IC socket 8 No. 6 x 12mm self tapping screws 4 32mm plastic spacers (see text) 1 3 AA cell battery holder 4 self adhesive rubber feet Small piece of tinned copper wire Light duty hook-up wire Semiconductors 1 PIC 16F84-04P (IC1) (programmed with MORSECLK.HEX) 1 78L05 5V positive voltage regulator (REG1) 4 1N4004 power diode (D1-D4) Capacitors 1 100µF 25VW PC electrolytic 1 10µF 16VW PC electrolytic 2 0.1µF MKT polyester 2 22pF ceramic Resistors (0.5W, 1%) 1 10kΩ 10mA when the buzzer is operating. While the circuit could be re-arranged to operate solely from 4 AA cells, with the regulator components removed, the expected operating time from the batteries alone would only be about 2-3 months. The batteries are only included to prevent the time settings from being lost when the unit is re­ located or when there is a blackout. If you choose not to use the backup batteries and the plugpack power is lost the time will need to be reset. Disassembled view of the Morse Clock. The 3-AA-cell battery holder is a little unusual – if you can’t find one, use a 4-cell holder with a dummy battery. mounting the smaller, passive com­ ponents (ie resistors and any links) progressing through to the larger ones, then the active components (semiconductors) and any on-board hardware (IC sockets, etc). Leave the installation of the PIC chip until the construction and initial testing is complete. Refer to the component overlay to ensure all components go in their correct spots and that any polarised components are installed correctly. Note that the two electrolytic capac­ itors need to be laid on their sides to avoid fouling the lid. The crystal is also laid on its side and held down with a piece of tinned wire soldered to the pads underneath the board. When installing the buzzer, make sure it is mounted flat against the PC board so that the when the lid is in place, the pushbuttons protrude sufficiently out of the lid. The buzzer positive lead is the longer one and Construction Construction of this project is straightforward. Start by checking the PC board for faults, looking for bridges across tracks and open cir­ cuit tracks. While there is no “right” or “wrong” sequence to installing the components, we usually start by 70  Silicon Chip Fig.2: the PC board component overlay. Note that the two electroyltic capacitors and the crystal must be laid over to fit under the case lid. connects to pin 1 of the PIC. Once the PC board is completed, it’s time to mark and drill the holes in the case. The PC board is mount­ ed on four pillars made from 32mm plastic spacers. These are screwed to the bottom of the case and the PC board screws to their top, just far enough down from the lid to allow the push-buttons to poke through. Unfortunately the 32mm spacers are just too long for this so we have to cut them down a little. First, place the PC board inside the box on the right side, butting up against the integral pillars. Align the PC board so the buttons and the buzzer are placed on the centre line of the base. Mark the spots for the mounting holes with a pencil and drill clearance holes for the self-tap­ ping screws. Drill a suitable hole for the DC connector on the rear side. Mount the DC connector and solder two wires to the socket long enough to easily reach the PC board power pins. Take the four 32 mm spac­ ers and carefully cut each of them to a length of 28 mm with a fine toothed hack saw. The plastic spacers used in the prototype have holes in each end that allow a No. 6 self-tapping screw to be inserted. Screw the four pil­ lars to the inside of the case bottom and then place the PC board on top of the spacers and screw into place with the four remaining self-tapping screws. You will also need to drill three holes on the centre line of the lid for the switches This same-size view shows that all fits in quite nicely into a standard 130 x 67 x 44mm and the buzzer. The switch­ Jiffy box. The PC board mounts on 28mm spacers to place the push-button switches at exactly the right height when the box lid is screwed on. es have a round body and the hole needs to be just big the batteries and install the PIC chip for hourly chime turned off. Pressing enough to allow the switches into the socket. Note the orientation the SET button toggles between the to move freely. The hole for the buzzer – pin 18 is closest to the crystal. settings. needs only to be equal to the hole in Connect the plugpack supply and you (3). Press the TIME button to access the top of the buzzer body to allow the should be greeted with the wonderful the 12/24 hour function. The number sound of the buzzer to escape when sound of slow Morse sounding the 1 is sounded to indicate 12 hour time the lid is in place. and number 2 for 24 hour time. Press­ Solder the DC connector wires to letters OK. Press the TIME button and you should hear the time being ing the SET button toggles between the PC board supply pins and the the settings. battery holder wires to the battery announced. Don’t worry about what it (4). Press the TIME button to access pins, ensuring that the positive and says at this stage, because we haven’t the AM/PM function. AM is sounded negative leads go to the correct posi­ set the time yet. Install the batteries again and then for AM and PM for PM setting. Press­ tions. The battery holder fits neatly in remove the plugpack. Press the TIME ing the SET button toggles between the gap left in the lefthand side of the button and verify that the clock is the two settings case. You could add a small piece of (5). Press the TIME button to ac­ foam as a packer to stop the battery still working with only the backup batteries. You will probably notice cess the fast/slow Morse function. F holder moving if you wish. that the output from the buzzer is is sounded for fast Morse and S for To prevent the mounting screws lower in level. This is normal and as the slow Morse setting. Once again scratching your desk and to make the clock less likely to slip around, attach stated earlier, the back up batteries the SET button toggles between the four self adhesive feet to the bottom are really only included to keep the two settings. clock going if the main power is lost (6). Press the TIME button to access of the case. for a short period. the Hour function where H is soundTesting Install the lid, reconnect the plug ed. Press the SET button and a beep Once construction is complete, it pack and your Morse clock is now will be heard. Each beep represents an increment of one hour, starting from is time to apply power to the circuit. finished. zero. In this mode the SET button Leave out the batteries at this stage Setting the time automatically repeats. If you do not and connect the plugpack to the DC Setting the time with the Morse press the SET button the hour setting socket. Using your multimeter, meas­ is unchanged. If the hours are set to ure the voltage at the output of REG1. clock is very simple, because there are only two buttons to press. Follow an illegal number, that is over 12 or You should read about 5.5V, and also you should read about 5V at pin 14 of the steps below to set the time and over 23, they are reset to zero and start again. the IC socket. If not, remove the power program the functions: (1). Press the TIME and SET but­ 7. Press the TIME button to access source and check your wiring again the Minute function where M is and the installation of the polarised tons together. The letters PGM are announced in Morse code, indicating sounded. Press the SET button and components. you are in program mode. a beep will be heard. Each beep rep­ Assuming this is correct, remove (2). Press the TIME button to access resent an increment of one Minute, the plugpack supply and install the batteries. Measure the voltage at pin the hourly chime function. The cur­ starting from zero. In this mode, the rently set option will be announced, SET button automatically repeats. If 14 of the IC socket again and this time it should be about 4V. If so, remove either ON for hourly chime or OFF you do not press the SET button the December 2000  71 Learning Morse Code While Morse code is no longer used in most commercial activities, some knowledge of Morse is required, at least for the next year or two, to gain a full privelege amateur radio licence. (The requirements have recently been changed to allow those who pass the 5 words per minute (wpm) Morse test to have access to all amateur bands. In the past, 10 wpm was the standard). So why learn Morse code? It’s still a viable means of communication; it’s still used by the armed services (eg, where ships are in line-of-sight to each other and radio communication might be eavesdropped, “Aldus” lamps are still used which flash Morse messages via light). But perhaps more to the point, if you listen in to the amateur radio bands (particularly the HF bands) you’ll hear amateur operators communicating with each other solely in Morse – for the shear pleasure of it. If you want to learn Morse code, listening in to the amateur bands is one of the best ways to go. Not one of the 20, 30 or 50 wpm speedhogs but slow Morse, often used by Novice operators. Or you could obtain one of the many tapes available which teach Morse code. And there are even many computer programs around which generate Morse from either a keyboard or from ASCII text and sound it via the computer speaker. The point is that Morse is an aural language, not visual. And while we’ve printed the Morse alphabet and numbers below, you will notice we haven’t shown it below )as dots and dashes – it is shown as dits and dahs – and should always be spoken that way. So the letter “A” is not dot dash, it is di’dah. “F” is di’di’dahdit, not dot dot dash dot. Note that if a "dit" is followed by another element (either dit or dah) we don’t pronounce the “t” in that dit – the T and the following D become effectively the same sound. The other main thing to remember when learning Morse is NEVER to start trying to send letters before you have thoroughly learnt to receive the whole alphabet. It’s very tempting to grab a Morse key or even a push-button switch, connect it to an oscillator and start bashing away. But your timing will almost certainly suffer if you haven’t got a good knowledge of Morse from reliable sources - others will find your Morse difficult, if not impossible, to decipher. Some letters are recognised very easily – if only because they form parts of common words or phrases. Who doesn’t know SOS, for example? Or “V” for victory (also known as the start of Beethoven’s fifth symphony – didididah). Other letters are easy because, well, they ARE easy: A (didah), E (dit) H (didididit) I (didit), M (dahdah), N (dahdit), O (dahdahdah) and T (dah). Even R (didahdit) and K (dahdidah) aren’t too difficult. There are other letters which are recognised because they are part of commonly heard expressions – especially on radio. “CQ”, or a general call to all stations, is one example. “HI” is another. And the universal radio greeting, “73”, makes a seven and a three easier. It’s when you start getting into some of the more obscure three-sound and four-sound combinations that Morse gets a little tougher – and some letters, such as B (dahdididit), C (dahdidahdit), F (dididahdit) G (dahdahdit), J (didahdahdah), L (didahdidit), P (didahdahdit) Q (dahdahdidah) W (didahdah) X (dahdididdah), Y (dahdidahdah) and Z (dahdahdidit) are regarded as the most difficult to recognise quickly. So you might have to put a lot more effort into these. Some people find learning “opposites” helps them: eg, R and K. Others find putting letters into similar sets works – eg A, U, V. Others simply get stuck in and learn the lot! Numbers are easy to remember but harder to recognise. That’s because numbers follow a pattern – one is didahdahdahdah, two is dididahdahdah and so on, but they have five-sound combinations. So when you start to hear a “1”, it could be an “A”, then a “W”, then a “J” then finally it becomes a “1”. Fortunately, most of the time when numbers are sent you’re probably expecting to hear a number, rather than a letter, so you’re more attuned to it. OK, enough of the preamble. Here is the full Morse code, including some punctuation. Gee, we hadn’t even mentioned trying to learn punctuation, had we? A B C D E F G H I J di’dah dahdi’di’dit dahdi’dahdit dahdi’dit dit di’di’dahdit dahdahdit di’di’di’dit di’dit di’dahdahdah N O P Q R S T U V W dahdit dahdahdah di’dahdahdit dahdahdi’dah di’dahdit di’di’dit dah di’di’dah di’di’di’dah di’dahdah K L M dahdi’dah di’dahdi’dit dahdah X Y Z dahdi’di’dah dahdi’dahdah dahdahdi’dit 72  Silicon Chip 1 2 3 4 5 6 7 8 9 0 di’dahdahdahdah di’di’dahdahdah di’di’di’dahdah di’di’di’di’dah di’di’di’di’dit dahdi’di’di’dit dahdahdi’di’dit dahdahdahdi’dit dahdahdahdahdit dahdahdahdahdah di'dahdi'dahdi'dah dahdahdi'di'dahdah error di’di’di’di’di’di’di’dit . , Fig.3 (left): you can photocopy and glue the front panel artwork to the lid of your Morse Clock. It also makes a great drilling template. Fig.5 (right) is the samesize PC board pattern. SILICON CHIP A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 1 2 3 4 5 6 7 8 9 0 minute setting is unchanged. If the minutes are set to an illegal number, that is over 59, they are reset to zero and start again. Each time a minute is incremented the internal seconds counter is reset to zero. In this way you can accurately set the time by using a reference clock with a second hand. Increment the min­ utes up to 1 less than the amount required, and select the desired minute at the moment the second hand reaches 12 on the reference clock. Obviously, setting the time will be easier if you select a time just after an hour has passed. 8. Pressing the TIME button again will return you to the hourly chime function. Pressing both but­ tons at any stage during program mode will store the settings, exit from program mode, sound the letters OK and return to normal mode. Software For those who program their own PICs, there are two files available for downloading from the SILICON CHIP website. The files are MORSECLK.ASM and MORSECLK.HEX, both zipped into a single file, morseclk.zip. While you do not need the ASM file to program the PIC, it will be of interest to those who dabble in programming. It is always interesting to see how some­ body else did it and maybe pick up a trick or two. The program runs in a small main loop that monitors the buttons for a press and also checks if the hour is up to chime the time. Each 20ms, an internal interrupt occurs that forces the PIC to update the time registers in the interrupt routine. The rest of the code looks after the sounding of the dots and dashes and setting the various functions. Have fun and hopefully your clock will prove both as well as being a novelty. While Morse code may be some­ what outdated in the modern tele­ communications world, it still holds a certain fascination and throughout its history has served us well in both SC peace and war. With one of these . . . ...you could have one of these in about 1 HOUR! Introducing The Quick Circuit 5000 If you want fast, no-fuss PC-board prototypes, take a look at the Quick Circuit 5000. This PC-controlled milling machine reads the standard files generated by popular PC design packages and mills away the copper on the board to produce the tracks. It then drills the holes and cuts out the finished product. You can go from design to finished product in about one hour – without using any messy chemicals. Check out the November 2000 issue of SILICON CHIP for a full review Phone SATCAM on (02) 9807 SC 7081 or email satcam<at>ozemail.com.au December 2000  73