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Part 2 – construction, testing and loading the software MIDI THEREMIN by John Clarke By now you are probably desperate to play a few compositions with the MIDI Theremin. But first you need to build it and install the software. Setting up the MIDI Theremin is quite detailed, so read carefully! F ollowing the circuit description of the MIDI Theremin in the first article last month, we shall now describe the construction and setting up procedure. Software will also need to be installed and to do this you’ll need to download some files from the ’net. Firstly, though, let’s start building the MIDI Theremin. Construction. The SILICON CHIP MIDI Theremin is constructed using two PC boards. The main PC board is coded 01204051 and measures 187 x 104mm, while the dis- play PC board is coded 01204052 and measures 142 x 99mm. The assembled PC boards are housed in a plastic box measuring 197 x 113 x 63mm. Begin construction by checking the PC boards for correct hole sizes and that there are no breaks in the copper or shorts between tracks or pads. Hole sizes for the corner mounts on the display PC board and for the LCD module should be 3mm diameter (~1/8”). Check the mounting holes for the external jack socket, the DC power socket, the DB9F serial connector and the MIDI output socket are all correct. Check also that the PC board to fits into the box neatly at the side pillar clips without bowing the box. If the box does bow out, the edges of the PC board will need to be filed off by a small amount so that it is a better fit. We assume that the Theremin is being built from the Jaycar kit (the only place you can get it!) – in this case all the holes in the box will have been milled out and a screen-printed front panel will be supplied. Display board Start assembly with the display PC board. Its overlay is shown in Fig.1. Insert the link first so you don’t forget Ludwig van, eat your heart out! You can become a composer with the MIDI Theremin and sequencer software! 62  Silicon Chip siliconchip.com.au Your friends will RAVE about your MIDI Theremin when they hear you playing like a pro! All you need is the MIDI Theremin and a MIDI Synthesiser – and if you own a PC, chances are you already have one of those! Here’s our MIDI Theremin working with the recommended “Rave” software on a laptop running Windows XP. Naturally, you’d normally separate the MIDI Theremin and laptop before use so that the volume plate wasn’t influenced. it. Mount the LCD module using a dual 7-pin header to connect from the LCD module to the PC board. Solder the pins on the topside of the LCD display and on the underside of the display PC board. The two opposite corner mounting holes on the LCD module are held down using two M3 x 10mm screws and M3 nuts, with some Nylon washers placed in-between the display PC board and LCD PC board. The trimpot (VR4) and the 10mF capacitor can now be mounted, noting that this capacitor should lie on its side to provide clearance when the display assembly is secured to the lid. Insert and solder in the 34-way right angle header plug. The switches can be inserted the wrong way if you aren’t careful. They are mounted as shown with the flat siliconchip.com.au side of the larger switches oriented to the side of the PC board. Switch S7 is mounted with the wider spaced pins mounted in the horizontal plane. The display board is now complete but before moving on to the main board, give it a close check for solder bridges, dry joints or incorrect component placement. Main board Begin assembly of the main PC board (Fig.2) by installing the links and resistors. Use the resistor colour code table or measure them with a digital multimeter to ensure the right resistor is in the right place. Next are the diodes – taking care to orient them as shown on the component overlay. Again watching orientation, IC1, IC3 and IC4 can be soldered directly to the PC board. IC2 is mounted using a socket – the socket can be soldered in now but don’t insert the IC yet. The capacitors and crystal can be mounted next. Again, the electrolytic capacitors must be oriented with the polarity shown. Now mount the transistors and PC stakes. There are two types of transformers, white-cored and black-cored. T1 and T3 are white-cored T2 and T4 are black-cored. Don’t mix them up! Each transformer has three pins on one side and two on the other, so you cannot insert them the wrong way. VR1 and VR2 can now be soldered in. REG1 mounts horizontally, with a heatsink sandwiched between it and the PC board. Bend its leads at the correct position so they fit into the May 2005  63 S9 S6 S3 SERIAL PORT TO PC GAMES PORT MIDI OUT 5-PIN DIN SOCKET 8 16 2 TO DISPLAY BOARD D3 D4 4148 4148 1 µF 100k REG1 7805 470Ω 1 µF 100nF IC2 PIC16F88 220Ω 1 1 100nF 68pF Q3 100k 100 µF 1 1 ANT 100nF 1 1 µF 33pF 33pF 15040210 IC4 MAX232 1 µF X1 8MHz D6 10 µF 220Ω 220Ω 220Ω 1 1 9 1 µF 5 4 EXT INPUT DC INPUT NI MERE HT IDI M IC3 6N139 T3 (WHITE) 470 µF 10 µF 4148 1 2 LED1 100Ω 13 14 S2 10 µF S1 S4 JAYCAR 2-LINE x 16 CHAR LCD MODULE S5 10k VR4 S8 S7 NI MERE HT IDI M TO MAIN BOARD 01204052 D5 100Ω 220k TP4 100nF T1 (WHITE) 64  Silicon Chip 390pF T2 560pF 100nF (BLACK) 2.2 µF TP GND 100nF VR1 2k 2.2 µF TP GND 1k TP3 2.2k 10k 220k 220k 100nF 1k 11 IC1 LM358 10 µF 2.2k Q2 TP1 560pF 680Ω TP2 10k Q1 100k D1 4148 220k 680Ω 100Ω V5+ 100Ω 100k 68pF PLATE Q4 100nF T4 (BLK) 4148 VR2 2k 100k 10k 10k 10k 2.2k 2.2k 2.2k 390pF D2 100nF siliconchip.com.au Fig.3 shows the 34-way IDC connections using the 34-way IDC wire and the two IDC connectors. Orient the tabs on the side of the connectors as shown (note the red striped wire is pin 1) and clip the back of the connector with the wire in LOCATING SPIGOT UNDERNEATH 1 1 34-WAY IDC CABLE 34-WAY IDC SOCKET SPLIT IN TWO 34-WAY IDC SOCKET DISPLAY BOARD CABLE 9 1 Fig. 3 (above): the 34-way IDC cable 16-PIN IDC DB15 MALE IDC PLUG SOCKET (IDC CABLE SIDE) which connects the 15-WAY (REAR VIEW) two PC boards. The IDC CABLE split down the middle isn’t essential – it just makes the cable easier to flex. Fig. 4 (right): the Games Port cable, with a DB15 male plug connecting to a 16-way IDC socket via NOT USED a 15-way cable. Note that pin 16 of the IDC GAMES PORT CABLE socket is not used. 15 Wiring LOCATING SPIGOT ON TOP 8 holes while allowing the tab to be secured to the PC board and heatsink using an M3 x 10mm screw and nut. Insert and solder in the upright 34-way IDC header taking care to orient it with the locating tab to the inside of the PC board. Similarly, solder in the MIDI out socket, the DB9 connector, the right angle 16-pin header, the DC socket and the 6.35mm jack socket. Note that when the jack socket is oriented with the input towards the top, the switching contacts should be to the left and the wiping contacts for the jack on the right. If they are the other way around, remove the contacts from the plastic moulding and swap them around. LED1 is mounted with the longer (anode) lead to the left and as high on its legs as possible – leave just a millimetre of the shorter (cathode) lead under the PC board for soldering. The LED is later bent over to fit into the hole in the side of the box. When complete, place the PC board in the box and clip the edges into the integral box side attachments. Attach the nut to the 6.35mm jack socket. The display PC board can now be secured to the case lid using the 5 x 10mm tapped standoffs and M3 x 6mm screws. Connect short lengths of wire to the M3 and M4 eyelets. Now attach the hand plate to the side of the box using M3 x 10mm screws and nuts remembering to place the M3 eyelet onto the screw closest to T1. The antenna is secured with a nut once the M4 eyelet is placed on. These two component overlays and photographs should help you assemble the two PC boards. Fig.1, (opposite top) is the display board while opposite and below is Fig.2, the main board. The two boards connect together via the IDC cable above. siliconchip.com.au May 2005  65 place. Use a vyce to press the parts together. ‑To allow more flexibility of the cable, we split the IDC cable lengthwise into two sections by opening it up around the centre (you don’t have to be too exact!). Make the connection between the main PC board and display PC board Games port wiring (Fig.4) is similar to the 34-way wiring except that we use 15-way cable. This is secured to the DB15 connector using a vyce as before. Only 15 of the 16 pins of the IDC socket are used – locate the 15-way IDC cable by not placing the wire onto the left most pin (pin 16), as shown. Wiring can now be completed for the last potentiometer (VR3) and to the hand plate eyelet and antenna eyelet. These last two wires should be made as short as possible with just enough length to connect from the PC stakes on the PC board to the securing points for the plate and antenna. The wires for the power switch (S10) MIDI INVALID MIDI OUT SERIAL PORT are made using crimp connectors for the switch connections and soldered to the PC stakes on the PC board. Once again, give the finished PC board a good visual check for solder bridges, dry joints (or non-soldered joints – it’s easy to miss one or two!) and misplaced or wrongly oriented polarised components. Testing The Theremin is now ready for testing. Make sure IC2 is not in its POWER SWITCH S10 EXTERNAL PITCH ANTENNA (M4 EYELET) 9V DC IN 8 16 1 9 2 TO GAMES PORT 5 4 15040210 34-WAY IDC CABLE 1 1 NI MERE HT IDI M 1 1 V5+ 1 (STRIPE) VR3 VR2 DISPLAY BOARD (IDC CABLE SLIT AND TWISTED) MAIN BOARD VOLUME PLATE (M3 EYELET) POT VR3 (STRIPE) 13 JAYCAR 14 34-WAY IDC CABLE 1 25040210 2 NIMEREHT IDIM 66  Silicon Chip Fig.5: the interconnecting wiring is delightfully simple – most is taken care of via the 34-way IDC cable. The only other external wiring is to the power switch, potentiometer, the antenna and hand plate. siliconchip.com.au socket. Plug in the plugpack into the DC socket. Connect your multimeter common (black) lead to one of the TP GND PC stakes and connect the positive (red) lead of the multimeter to the input of REG1 (left pin). Switch on the plugpack at the mains and switch on S10. If you get a reading of about 9V, good. If the reading is zero, check that the DC plug for the plugpack is inserted correctly into the two pronged plugpack lead connection. You can rotate this connection by 180° – then check the voltage at the input of REG1 again to ensure you now get the 9V reading. Measure the output of REG1 (right terminal) for +5V. If this is not +5V (or very close) check the PC board for a short circuit. You should also be able to measure 5V between pins 5 and 14 of the IC2 socket and about 9V between pins 4 and 8 of IC1. On IC4 check for 5V at pin 16, -9V at pin 6 and 9V at pin 2. These 9V readings may be anywhere up to 9.6V. If the voltages are OK, turn the power off, wait a short time – say five seconds – and install IC2 into its socket, the right way around! Apply power and check the display lights up and shows characters. If you Here’s the display board installed on the case lid. Here you can also see the divided 34-way IDC cable – it’s essential to do this because the cable is twisted. cannot see anything on the display adjust VR4. This trimpot needs to be adjusted to give the best display contrast. Check operation of all switches by going through the switch functions described last month. Setting up Test points have been included to help make setting up a little easier. Custom-made Lithium Ion, NiCd and NiMH battery packs These provide connection points for your multimeter so measurements can be taken as you make adjustments. You will need either (preferably) a plastic alignment tool with a 3.5-4mm wide flat blade, or a screwdriver with the same type of blade, to adjust the slugs in the IF transformers. The plastic tool should not affect your readings: However, if using a metal screwdriver, you may need to NiCd/NiMH Smart Chargers www.batterybook.com (08) 9240 5000 Li-Ion Smart Chargers 2400mAh NiMH AA cells siliconchip.com.au High-quality single cell chargers with independent channels. Charge any combination of NiCd & NiMH AA and AAA cells Ask for a free copy of the Battery Book catalogue or visit www.batterybook.com May 2005  67 Parts List – MIDI Theremin 1 PC board, coded 01204051, 187 x 104mm 1 PC board, coded 01204052, 142 x 99mm 1 plastic box, 197 x 113 x 63mm (UB2) 1 antenna, 170mm long 1 hand plate, 80 x 70 x 1mm aluminium 1 2-line 16-character LCD module (backlit) 1 mini rocker switch (S10) 1 PC-mount 6.35mm switched jack socket 1 5-pin PC-mount DIN socket 1 DB15 IDC male plug 1 DB9 PC-mount right angle female connector 1 34-pin IDC header 1 34-pin right angle IDC header 1 16-pin right angle IDC header 2 34-pin IDC line sockets 1 16-pin IDC socket 1 7-way DIL header 1 9V 150mA DC plugpack 1 PC mount DC power socket 8 SPST PCB mount snap action switches (S1-S6, S8,S9) 1 SPST micro tactile switch (S7) 1 5kW 16mm linear potentiometer (VR3) 1 knob to suit VR3 1 18 pin IC socket 1 heatsink 19 x 19 x 10mm 1 8MHz crystal (X1) 5 10mm tapped spacers 10 M3 x 6mm screws 5 M3 nuts 5 M3 x 10mm screws 6 3mm ID Nylon washers 1 3mm crimp eyelet 1 4mm crimp eyelet 2 crimp spade female connectors for switch 2 coils, second IF, white, (T1,T3) 2 coils, third IF, black (T2,T4) 1 serial DB9 cable (male to female) adjust the slugs in small steps taking the screwdriver away from the transformer slug to take the readings. Also take care if using a metal screwdriver that you do not crack the brittle ferrite transformer cores. Do not force the slug past its end stops. A small 2.5-3mm flat bladed screwdriver will also be required for adjusting trimpots VR1 and VR2. Connect your multimeter between 68  Silicon Chip 1 30mm length of 0.8mm tinned copper wire 1 220mm length of 34-way IDC wire 1 2m length of 15-way IDC wire 1 100mm length of black hookup wire 1 100mm length of green hookup wire 1 150mm length of yellow hookup wire 11 PC stakes Semiconductors 1 LM358 dual op amp (IC1) 1 PIC16F88 programmed with midith02.hex (IC2) 1 6N138 optocoupler (IC3) 1 MAX232 RS232 receiver/driver (IC4) 1 7805 three-terminal 5V regulator (REG1) 2 BC547 NPN transistors (Q2,Q4) 2 2N5484 JFETs (Q1,Q3) 1 1N4004 1A diode (D6) 5 1N4148 switching diodes (D1-D5) 1 5mm red LED (LED1) Capacitors 1 470mF 16VW electrolytic 2 100mF 16VW electrolytic 5 10mF 16VW electrolytic 2 2.2mF 16VW electrolytic 5 1mF ceramic 4 100nF ceramic 4 100nF MKT polyester 2 560pF ceramic 2 390pF ceramic 2 68pFceramic 2 33pF ceramic Resistors 1/4W 1% 4 220kW 5 100kW 5 10kW 5 2.2kW 2 1kW 2 680W 1 470W 4 220W 4 100W 2 2kW top turn multiturn trimpots (VR1,VR2) 1 10k horizontal trimpot (VR4) one of the TP GND terminals and TP1. Using the alignment tool, adjust T2 for a reading of about 0.9V while your hand is away from the hand plate. Now move your hand close to the hand plate. The voltage should fall just slightly – by about 0.06V or so. If the voltage goes up instead, then the core will need readjusting. Take your hand away from the hand plate and turn the core anticlockwise, so that you see the voltage rise to a maximum and then fall again. Stop turning when the voltage reaches 0.9V again. Note that the rise and fall in voltage may not happen before you run out of adjustment (where the slug cannot be wound anticlockwise any more). In this case, turn the core in T1 clockwise by one turn and the T2 core clockwise by more than one turn, then adjust anticlockwise again, stopping at the point where the voltage falls to 0.9V. Now transfer the multimeter lead to TP2 and adjust VR1 for a reading of about 6V making sure your hand is away from the hand plate. Now move your hand close to the hand plate. The voltage should go down to near 0V. This adjustment is critical and can change when the lid of the Theremin is placed on the box. The adjustment is affected by lead dress inside the box and so some readjustment may be necessary later to have the hand plate operation work over a satisfactory range of hand movement. Adjustment of the antenna circuit is the same as for the hand plate. In this case place the meter between TP GND and TP3 and adjust T4 for the 0.9V reading. Readjust T3 clockwise if you cannot find the position for T4 where the voltage falls from 0.9V when your hand is brought near to the antenna. Adjust VR2 with the multimeter re-attached to TP4 for a reading of about 6V with the hand away from the antenna. To make the final adjustment, place the MIDI Theremin lid on and select the Note display. Observe the volume and note values. The volume can be controlled from 500 when the hand is away from the plate down to 0 with your hand close to the plate. If the volume shows less than 500 with the hand away from the plate, readjust VR1 (you’ll need to take off the lid again!) for the 500 reading. Adjust VR1 so that the volume starts to fall from 500 when your hand is around 100mm from the plate. Similarly, when adjusting VR2, set this so that the top note begins to change at about the 100mm mark as your hand is brought closer and closer to the antenna. The top note will be C6 for the normal range setting and G8 in the wide setting. For really precise tuning, adjust VR2 with the antenna extended by about 10mm. Then when the lid is closed siliconchip.com.au Capacitor Codes Value IEC Code EIA Code 1mF 1m0 105 100nF (0.1mF) 100n 104 560pF 560p 561 390pF 390p 391 68pF 68p 68 33pF 33p 33 on the Theremin, you can shorten or lengthen the antenna slightly to obtain the best results from the antenna control without having to open the lid. External control If an external foot control is required instead of the auxiliary potentiometer, a suitable design was published as part of the Waa-Waa Pedal in the September 1998 issue of SILICON CHIP. Naturally, you won’t require anything but the pedal itself; however full pedal constructional details are given in that article. Use dual-cored, shielded cable for the interconnection, with the earth braid connecting to the common terminal on the stereo jack plug and the earth end of the potentiometer. Also note that the pot used in the MIDI Theremin is a 5kW linear, not 10kW to 50kW as used in the Waa-Waa Pedal. A socket could be installed on the footswitch as shown in the original design or you could use a fixed lead from the foot switch to the jackplug. This later alternative is the wiring shown for the potentiometer in Fig.6. You can obtain a back issue of September 1998 or a copy of the article for $8.80 from SILICON CHIP. Software As mentioned last month, if you want to use the MIDI Theremin with a computer, you will need to install sequencer software. The software provides the means to send a MIDI signal to the computer and to drive the sound card’s synthesiser. There are many sequencers available on‑the market including Cakewalk, Propellerhead’s Reason, the ComputerMuzys CM Studio and Rave. We have tested the MIDI Theremin on the last three. By far, the easiest-tooperate sequencer is Rave. You can use other sequencer software if you wish, however, we recommend using Rave first unless you are already well versed in using them. siliconchip.com.au POT TIP SLEEVE RING Many sequencers are a little daunting when you start them up, due to their hugely complex control features. The Rave sequencer is ideal for firsttime users as it is easy to use and has sufficient features for use with the MIDI Theremin. In fact, we believe most people will be completely satisfied with this sequencer. If you plan to use a different sequencer, it must be able to accept incoming MIDI signals and direct them to the sound card’s synthesiser. Some sequencers do not do this and only send the MIDI signal back out through the MIDI output on the computer. This means that the computer’s synthesiser will not generate any sound. The Propellerhead “Reason” software is available on the net as a demo version with a “no-save” feature and an after-20-minute automatic shutdown. It must be purchased if you want to continue to use it (www. propellerhead.se). The Computer Muzys CM Studio is usually available on the CD supplied with “Computer Music” magazine from Future Publishing in the UK. Check it out at your newsagent. This software requires a minimum 500MHz PC or MAC (www.comptermusic. co.uk). RAVE for Windows is available as a free download from the ’net (www. files1.sonicspot.com/rave/rave.zip). This software (or another sequencer program) is the only software you will need to install if you are connecting to the computer using the sound card input via the games port. In this case make sure the Port settings on the MIDI Theremin are <DRIVE> VIA MIDI OUT & GAMES PORT. What, no games port? If you do not have a games port input, then you can connect via a serial port, or failing this using a USB port via a USB adaptor. USB connection is the most finicky way of operating the MIDI Theremin and if you have a serial port it is recommended to use it rather than via USB. If you are not convinced that the 6.5mm STEREO PLUG RING SLEEVE TIP Fig.6: if you want an external control (including a foot pedal) here’s how to wire the pot to the 6.5mm stereo plug. serial connection is best, read the notes concerning USB operation in the section describing installing the USB driver. For USB use, there are two options. Firstly, you can use a Serial-to-USB converter and this is used in conjunction with the MIDI serial driver. Software to setup a USB to virtual serial port driver will be required and this is supplied with the Serial to USB converter. (See overleaf for the USB installation). For this option the Port settings on the MIDI Theremin will need to be set to <DRIVE> VIA SERIAL PORT ONLY. Alternatively, if you use a MIDI-toUSB converter (available from music shops) then you only need to install the sequencer software and the MIDIto-USB driver. In this case make sure the Port settings on the MIDI Theremin are <DRIVE> VIA MIDI OUT & GAMES PORT. The MIDI-to-USB converter connects directly into the MIDI outlet on the Theremin. Software drivers for this converter should be supplied with it. We will only describe setting up the Serial-to-USB converter since this is the cheapest option. You’ll find the complete setup procedure in the panels on the next four pages. Where do you get the kit? This project was sponsored by Jaycar Electronics, who hold the copyright on the design, PC board layouts, etc. Kits are available from all Jaycar Electronics stores and most resellers. The complete kit of parts (KC 5410) as described here, including hand plate, antenna, case, silk-screened front panel and a mini stand, sells for $159.00 A suitable power supply is the Jaycar M-3003 selling for $13.95 For more information, refer to Jaycar’s website: www.jaycar.com.au May 2005  69 Checking your computer settings and inst When installing any programs or drivers, you need to be logged on to your computer as an administrator. Before installing the sequencer software, it is best to check the settings in your computer to make sure that sound card is set up correctly for MIDI. For Windows XP select Start/control panel. Then switch to ‘classic view’ if it is set in the ‘category view’ mode. Now select sounds, speech and audio devices/audio/ midi music playback. In the MIDI music playback, select an MPU-401 compatible synthesiser (eg Microsoft GS Wavetable SW synth) Also make sure volume is up for the synthesizer. Do this by selecting volume in the MIDI music playback box and checking settings for the SW Synth. This is similar for Windows 98. In this case select Start/settings/control panel/ multimedia/. In the multimedia properties select MIDI and an MPU-401 compatible synthesizer for internal synthesis. (eg. ESFM Synthesis (220)) Also in Start/programs/accessories/entertainment/volume control. Check that volume control level for synthesizer is up. Driver signing Later versions of Windows include driver signing. You need to check that this is not set to block programs from being installed. To check the settings in Windows XP, select Start/control panel/hardware/driver signing. Click on the Warn only button, if not already selected. The zip file is 647k bytes and must be unzipped before use. If using Windows 3.1, you’ll need to use PKunzip to extract the zipped files. The software was written to run on Windows 3.1. We have tested it on Windows 98, Windows ME and Windows XP. The only problem we have experienced during installation is where error messages are shown because the DOS help file is not installed on the computer. This occurs because the software was written for Windows 3.1 and the operating system relied on having DOS installed. Once the Rave software is installed, the error messages do not affect the operation of the RAVE sequencer. Download the rave.zip file from the location shown above and save the file to a directory (or folder) called C:\rave (or similar). When the file is unzipped, install the software using setup.exe. During installation the computer may ask if you want to run this software with an unknown publisher. In this case click on the run tab. As mentioned, if you are using a current version of Windows that does not include DOS; there will be an error message saying could not open the file c:\dos\doshelp.hlp. Click on ignore. A similar DOS shell error will also be shown. Again, click on ignore. Click on close after the general protection fault error is shown. When installation is complete, use Windows explorer or file manager go to the folder c:\rave. Single click onto rave.exe (c:\rave\ rave.exe) then to “File” and then select create shortcut from the list of options. Drag the shortcut to the desktop (this does not apply with Windows 3.1). Also copy the midiout.drv file (found in the to the c:\rave folder to the c:\windows\system folder. If you wish to uninstall RAVE, locate the c:\rave folder and delete it and all files it contains. Delete the desktop shortcut and remove the midiout.drv file from the c:\ windows\system folder. Serial or USB operation If you are connecting to the serial or USB port, you will need to install the required drivers now. Details are in the separate serial port driver section and Serial-to-USB section. Don’t forget that if you are using the serial- to-USB converter, the MIDI serial driver will also be required. For a MIDI-to-USB driver install as per the instructions supplied with it. Running Rave To start up Rave, double click the Rave shortcut on the desktop. A Rave copyright box will appear. Click on the ok button. Setting up RAVE Select the Options and the “midi thru” box. Rave Installation The sequencer program is available from www.files1.sonicspot.com/rave/rave.zip 70  Silicon Chip siliconchip.com.au talling the MIDI Theremin software This will bring up a tick against the MIDI Thru. The sound card synthesizer will not produce any sounds unless this box is ticked. Check that the Options/Metronome/Bars Count In is set to at least 1 (if this is set to zero you will not be able to record) . Check in the Options/Output Assignments. The settings should show the MIDI Mapper. Recording To record, select File/new. Save as ‘yourfilename’.blk. Click onto the REC(ord) button to begin recording. The tape transport position marker will start to count up after a second or so and you are now recording. The stop, fast wind and stop buttons operate the same as any tape or video recorder. So you can stop, rewind and play the composition. Saving the recorded composition is done by selecting File/save. Once you have saved a track you can multitrack record if you want to. This lays down another recording alongside the original recording. So you can playback with more than one track, as though there is more than one Theremin playing, or you can record another instrument such as a keyboard to accompany the Theremin. To multi-track record Left click the mouse pointer in the track name block (eg, where silicon chip 2 is positioned) to select second track. These are initially set with an unnamed label but they can be renamed by right clicking the mouse pointer on the word and use the backspace to delete the word. Rewrite your own required filename. The selected track can then be recorded as a separate track with the original recording. Up to 32 tracks can be recorded. In the right hand blocks, there is the option to change the patch (instrument), the volume, pan and quantisation. Play around with these options to understand the changes they make. Playing the MIDI Theremin You are finally ready to play the Theremin! Connect up the serial, USB or games port lead between the MIDI Theremin and the computer. Switch on the MIDI Theremin and check that you can play the instrument and hear it through the sound card output using headphones or loudspeakers. If you cannot hear anything, first make sure the volume is turned up on the computer and that the sound works on other mediums such as the CD player. If the CD player works and sound still cannot be heard with the Theremin, double check the MIDI Thru is ticked in the RAVE/ Options settings and that you have selected the correct port in the settings menu on the MIDI Theremin. Also check the settings as mentioned in the MIDI serial driver section and the Serialto-USB sections. siliconchip.com.au The recorded composition can also be shown in music format. Select Edit/Score editor to show the traditional five line (musical staff) format of the recorded composition. Particular notes can be selected with the mouse pointer and its value (eg, B2 for note B in the second octave) is the same as shown on the MIDI Theremin. Note that extremely complex compositions using the Pitch Glide control may cause the software to overload when selecting the Score editor. This is a basic rundown on how to use the software. It is sufficient to enable you to play and record plus do some multitracking if required. From here on, you’re on your own. The only way you will discover the full potential of the MIDI Theremin is to play with it. Enjoy! Installing the serial driver The serial driver is commercial software written by Yamaha Corporation for their MIDI musical instruments. It supports Windows 95, 98, ME, NT, 2000 and XP. The driver automatically detects your operating system and installs one of two versions best suited for your computer. Both files are contained in a file called cbxdrv201w.zip. This is a 971Kb file and is designed for use with COM1 or COM3 port on the computer. When using with a serial port connection, make sure that you have a free COM1 or COM3 port on your computer before installing the driver. In some cases you may be using the COM ports for a serial mouse and/or external modem. You may have to free up one of these ports so you can use the MIDI Theremin with this serial port driver. In general, the Modem connection could be used or if you only have one serial port, use this and connect your serial mouse to a USB port using the commonly available USB-to-serial converters available (one may well have come with your mouse) or buy a USB mouse – they are very cheap these days. When used in conjunction with a USBto-serial converter, the COM port numbers apply to the virtual serial port created with the USB-to-serial driver software (see its installation in the separate section). The Yamaha serial driver file can be obtained from: www.yamaha.co.uk/xg/ download/tools/cbxdrv201w.zip Save the file to a directory (or folder) called c:\midicbx (or similar) and unzip it. A readme file will be unzipped to c:\midicbx\ cbxdrv201w\setupdir\009\readme.txt and this describes in detail how to set up the driver for the various Windows operating system versions. Basically, all you do is double click on the setup.exe (found in the setup folder) file and follow the prompts. When the “select COM ports” dialog shows, check COM1 or COM3. The selection is dependent on how many serial ports you have and which one you are going to use for May 2005  71 the MIDI Theremin connection. If you are connecting via USB, select a COM port that does not correspond to a serial port that is already installed. classic view, then select sounds, speech and audio devices/audio/midi music playback. In the MIDI music playback, select the down arrow to check if YAMAHA CBX A Driver is installed. Do not select this driver, we are just looking to see if it is there, so keep the original SW Synth setting. Once installed, you can change settings and disable the driver without uninstalling it. To do this select Start/Control Panel and double click on the Yamaha CBX driver Icon. Click on the Next button and the MIDI output ports dialog will be shown. Select the ‘Use single MIDI output port’. When you double click on the YAMAHA CBX Driver Icon, the CBX Driver Setup box will be displayed. You can select the COM port (again) and enable or disable the driver. The greyed out selections cannot be used. Click on Next and that completes the installation. The following dialog box will be displayed. It reminds the user to select the PC-2 position on the Yamaha MIDI units ‘To Host’ select switch. For our MIDI Theremin it reminds us to select the serial port setting on the Theremin. Restart the computer to finalise the installation. (Yamcbxdv.bmp) Correct installation can be seen in the ‘sounds and audio devices’ properties box. For Windows XP select Start/Control Panel in When using this driver with RAVE you can see if it is connected correctly by selecting Options/Synchronisation. If correct the Yamaha CBX Driver will be displayed in the Synchronisation input port box. USB Operation (via serial to USB converter) When connecting the MIDI Theremin using a USB port, you will need a USB-to-serial (DB9) converter, which converts the serial signal from the MIDI Theremin’s serial port output to a USB signal. A suitable device is available from Jaycar Electronics, cat number XC-4835. The software supplied with this converter then produces a virtual serial port on the computer. This virtual port can be read by the Yamaha MIDI serial port driver that is already installed. Both the virtual serial port and the MIDI serial port driver must be set to the same COM port. Note that if you have a serial port on your computer, it is preferable not to select the same COM port number for the virtual port. To install the USB-to-serial converter and the software, plug in the USB unit to a USB port on the computer. The computer will alert that new hardware has been installed. In Windows XP, the Add New Hardware Wizard will start up and assist in setting up the USB converter. When prompted, select insert the CD ROM disk into the computers CD drive and select the ‘USB to serial cable’\ WN DRIVER\98-2009-2K20021 folder. Click next to install. If you have problems with this method, disconnect the USB to serial converter, wait a short time (say ten seconds) and reconnect. Wait until the new hardware has been detected and the ‘add new hardware’ wizard opens. Select the ‘install from a list or specific location’, then click next. Select ‘Don’t search I will choose the driver to install’ and click next. Click on ‘Have disk’ then browse to the CD ROM\WN Driver\982009-2K20021\serspl.inf. Click on open, ok and next. A warning may appear to say that the software is not logo tested for compatibility with windows. Click on the ‘continue anyway’ button. Uninstalling or reinstalling Removing the YAMAHA CBX Driver Navigate to the c:\midicbx folder and double-click the setup.exe. The Setup dialog will appear. Follow the prompts to remove the driver. Restart the computer to complete the removal. 72  Silicon Chip Make sure the USB-to-serial driver is plugged into the computer. Select Start/ Control Panel/system. In the system properties select hardware/device manager/ ports (COM & LPT). Select the ‘Prolific USBserial-bridge’. Double click on this then select Driver/uninstall and ok when it prompts you to uninstall. You can reinstall using this method by selecting the update driver button and direct to the folder on the CD ROM as before. To change the COM port setting on the USB to serial converter, select Start/Control siliconchip.com.au Panel/system. In the system properties select hardware/device manager/ ports (COM & LPT). Select the ‘Prolific USBserial-bridge’. Double click on this then select port settings/advanced. Select the COM port number from the drop down menu. Note that the port number must match the port number selected for the Yamaha MIDI serial port driver. You can only select the ports that the Yamaha MIDI serial port driver allows. In our case as shown in the Yamaha CBX driver setup this is COM1 or COM3. Note that it is unnecessary to alter the port settings apart from the COM number as the USB to serial driver sends at its maximum rate regardless of the port settings. This is true even though the serial signal from the MIDI Theremin is sent at the 38400baud rate and the rate is set to a different value in the settings. Notes on the USB connection 1. You can connect the USB-to-serial converter to the MIDI Theremin in one of two ways. First, you can use a DB9 extension cable. The cable connects to the MIDI Theremin serial outlet and the socket end connects to the USB-to-serial converter. Plug the USB end into the computer. Alternatively, if you only require a short connection, the USB converter can be directly connected to the MIDI Theremin serial outlet. In this case the retaining screws on the MIDI Theremin serial outlet will need to be removed and inserted from the inside of the box in order to secure the USB converter unit in place. A 1.8m USB 2.0 A to A extension cable can be used to make the computer connection. siliconchip.com.au 2. If you plug the USB-to-serial converter into a different USB port on the computer, you will need to install the driver for that USB port. It’s much better to always plug into the original USB port where the driver was installed (maybe label the USB input?). 3. Avoid plugging the USB-to-serial unit into the computer while the MIDI Theremin is switched on or the computer may sometimes decide the device is a mouse or similar human interface device rather than the USB converter. If this happens, you will need to reinstall the USB to serial converter software as detailed above or click onto the driver ‘rollback’ button instead of the ‘reinstall button’. This last option reverts the driver to the previous USB-to-serial driver and installation is quicker (and you do not need to find the CD ROM!). 4. If you see this panel when starting Rave, it means that the MIDI Theremin will not (at present) work with the USB converter. The panel indicates that the virtual port data is corrupted. It could be that the Serial-to-USB Converter is not connected, or simply that the USB converter has to be reset. Alternatively, the COM ports selected for the Yamaha serial driver and the USB to serial driver may not be the same one. In the first two cases, click on the ‘no’ button and then the OK on the copyright panel when Rave starts. Exit from Rave by clicking on the top right hand X button (or File\exit). Unplug the USB connection and wait for the disconnect confirmation, then reconnect it and start Rave again. The wave device-warning panel should not appear this time. 5. If you switch off the MIDI Theremin while you are within Rave, then the only way to have the MIDI Theremin play again is to exit from Rave and then restart Rave. Similarly in ComputerMuzys you may receive this error when starting. Muzyserr.bmp In this case exit from the program, disconnect the USB connection and reconnect it. Then restart the program. The Computer Muzys MIDI port is set using the System/ MIDI Hardware selection and the MIDI Hardware set-up panel will be shown. The reason? Following is a screen grab showing the Reason Sequencer demo version. Note the complexity compared to the Rave sequencer. The MIDI port is selected by clicking onto Edit then selecting preferences. Use the down button to select the page that shows MIDI. The port shows the Yamaha CBX driver is selected and the tick indicates that it is working. (reason.bmp) Apple Macintosh Computers Although we have not tried it, Mac users should be able to use the MIDI Theremin by using a Mac version MIDI sequencer. For example the ComputerMuzys CM studio and Reason 2.5 are available for the Mac. There are at least two options when making the connections between the MIDI Theremin and a Mac. You may need to visit a music shop and purchase a cable or converter. The simplest option is to use a MIDI-to-printer-port cable. The Mac already has MIDI drivers installed for this connection but it is only useful if you have a printer port. For USB connection you will require a USB-to-MIDI converter such as the Yamaha UX96. This converts from the MIDI outlet on the MIDI Theremin to USB format. The driver supplied with the converter will need to be installed. Alternatively, some Mac laptops supply a USB-to-serial converter and you may be able to use this when connected to the serial port on the MIDI Theremin. A music shop salesperson well versed in MIDI should be able to supply you with the necessary information and hardware SC required. May 2005  73