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Impersonate a Robot, a Droid or one of the many known interplanetary aliens such as Daleks, Cybermen, Klingons, Cylons or even Darth Vader... build this y r a t e n a l p ry nter IInterplanetary Voice Voice by John (call me ET) Clarke . . . and never be caught out, out of your galaxy. . . again! Be sure to blend in amongst diabolical characters at your next interplanetary meeting. By building the Interplanetary Voice you too can sound like a genuine alien character with a metallically challenged voice. Use it to develop instant rapport with any such alien that you meet. 24  Silicon Chip siliconchip.com.au I f you don’t want to cause a fauxpas of interplanetary proportions (perhaps even threatening life on Earth as we know it), having a correct sounding voice is a prerequisite if you are communicating with one of the myriad of science fiction characters that originate from extraterrestrial planets. Many of these characters are encapsulated in a metallic suit and not surprisingly have a metallic sounding voice. It is not uncommon for people on planet Earth to be aware of interplanetary aliens. They will know of the Daleks who originate from the planet Skaro and the Cybermen from Mondas. These characters are often portrayed in the TV series Dr Who. Undoubtedly, many will have heard (and for some the very last thing they hear) the terrifying and menacing phrase from the Daleks as they call out “exterminate, exterminate”. Other characters well known to the general public on the planet Earth include; the Klingons from Star Trek, Cylons from Battlestar Galactica and Darth Vader from Star Wars. We will surely be exposed to more characters of this type as we come to explore more planets in the Galaxy and beyond. One unfortunate characteristic of humans from the planet Earth is that they do not have the right sounding voice. Because of this, they are unable to communicate effectively with these interplanetary characters. You really require a voice changer to convert a normally boring humanoid voice into a strongly metallic version. In this way your voice can be well understood with all manner of creatures you may encounter from other planets. In the past, SILICON CHIP has assisted you with voice modifications by publishing several metallic voice changer projects. There have been two “Vader Voice” projects, one in September 1988 and the other in September 1995. A “Galactic Voice” was published in September 2006 and now we have (drum roll, if you please!) “Interplanetary Voice”. Interplanetary Voice is unique. It stands out as superior amongst these past projects and it is not because this project is published in a month other than September. Instead of generating sounds with non-specialised Integrated Circuits (ICs) as was the case for previous designs, Interplanetary Voice uses a dedicated voice changer IC, which produces a variety of magnificent metallic voice sounds. Undoubtedly, aliens from other planets use a similar Yes, we know you can buy these on eBay . . . We’re not saying that’s where the idea came from (hey, they might have got their idea from us!) but these type of devices are quite commonly available. The one shown here (from China, naturally) was purchased on eBay for about       $30.00 which is less than the parts cost for our version. (We don’t know which chip they’ve used ‘cos they’ve “blobbed” it over!) But we think ours is better!!! For a start, only about half the switch positions on the commercial one appear to do anything – and while it has some snazzy LEDs which flash around    the speaker when you’re talking, it’s a little-known fact that      most interplanetary aliens would find flashing lights the height of     rudeness and very, very insulting – and may well reduce you to a pile of ash in retaliation . . . siliconchip.com.au March 2012  25 TGU OSC1 OSC2 OSCILLATOR GENERATOR TIMEBASE GENERATOR TGD VIB ROB CONTROL CIRCUIT POWER ON CIRCUIT SW0 FVIB SW1 A0 AMPLIFIER SW2 COMPARATOR Ain A/D CONVERTER LATCH SRAM D/A CONVERTER AUDIO Vref Vdd Vss Fig.1: inside the Holtek HT8950 chip. It’s a dedicated IC made for the purpose of voice synthesis. voice changer IC. As we know, most ICs on planet Earth use a silicon-based semiconductor material but we suspect that the voice changer IC used by aliens is based on a semiconductor that differs from silicon. Not to worry though, because the silicon version of the voice changer does the job just as well as any of the alien versions; in fact, without evidence to the contrary, it could even be better. Interplanetary Voice is made in such a way that all you need to do is speak into it with a normal voice. Interplanetary Voice will do the conversion for you, producing a metallically accented sound via a loudspeaker. Unique housing Interplanetary Voice is housed in unique interplanetary-style “mouthpiece”. If you are actually from Earth, you may note that it has a decided similarity to a flared loudspeaker port but this is purely co-incidental. At the flared end is a small sound- TS producing device – again, earthlings may think this resembles a small speaker. The flare projects sound directly to an interplanetary alien’s earpiece. Additionally, the flare and loudspeaker grill will imitate many a metallic voiced character’s mouthpiece so you won’t be mistaken for an Earthling. Controls and microphone are mounted at the opposite end of the loudspeaker port. You can alter the volume with a rotary control and use pushbutton switches to set the voice effect depending on the characteristic sound you need. There are Robot, Vibrato and Effects selections available. A power switch is included as well as a LED indicator. Additionally, a LED varies in brightness to show the instantaneous volume level of your voice. Block Diagram The voice changer device used in Interplanetary Voice is the Holtek Semiconductor Incorporated IC designated LAMP the HT8950. This is fortunately available on planet Earth, though it does come from the alien land of Taiwan. Fig.1 shows the internal arrangement for the HT8950 IC. Voice signal input is applied to the op amp. This has the non-inverting input tied to a reference voltage, allowing signal to swing above and below the reference. Both the inverting input and output of the op amp are available at the IC pins so that the op amp can be set up as an amplifier. Signal from the op amp is converted to a digital value using an 8-bit analog to digital converter. An oscillator and time base generator set this analog to digital conversion sampling rate to 8kHz. The timebase also sets the storage rate of the digital conversion values into the static RAM. The latch presents and holds the SRAM values as they are clocked out and the digital to analog converter reconstructs the digital data to an analog signal. An external low pass filter removes Views of the Interplanetary Voice assembly from both sides, immediately before it is placed in its “speaker vent” case . . . 26  Silicon Chip siliconchip.com.au D1 1N5819 150 470 K S1 POWER A A LEVEL 3.9nF ELECTRET MIC 100nF TS TGU Vdd SW1 5 SW0 4.7k 100F  LED2 2 7 11 16 1 K Ao LED ZD1 3.6V 100F 100nF 9V BATTERY A POWER A 10 39k 1.8k K 470F  LED1 K 8 LK1 4.7k 6 14 + 47k 100k 13 12 15 17 18 VIBRATO EFFECT ROBOT S2 S3 S4 Ain SW2 3 10F OSC1 IC1 HT8950 OSC2 AUDIO 3.3k 9 VOLUME 3.3k VR1 50k LOG FVIB VIB 100nF 6 3 8 IC2 LM386N TGD ROBOT Vref Vss 4 10 510 1 10 100k 4 10F 10F SPEAKER 7 2 33nF 470F 5 47nF ELECTRET MIC 1N5819 LEDS A SC 2012 INTERPLANETARY VOICE ZD1 Fig.2: the circuit diagram consists mainly of two parts – the HT8590 custom chip and the LM386N audio amplifier. Operation is explained in the text. the higher frequency components from the digital to analog signal. There is no information about the signal processing used to produce the voice changing. We do know that the input signal can be frequency modulated at 8Hz when the Vibrato is selected on the Interplanetary Voice. The Robot selection on the Interplanetary Voice appears to produce a ring modulator effect where the input voice signal is multiplied by another frequency (derived from the Time Base Generator) to produce sum and difference frequencies. This causes an upward or downward frequency shift of the input signal plus a shift in the K signal harmonics. The modulation results in a metallic sounding timbre. Inputs to the Control Circuit allow for variation of the amount that the ring modulation frequency shifts the input signal. Selection ranges from lower frequency shifts at a factor of 0.888, 0.8 and 0.66 to higher frequency shifts of 1.33, 1.6 and 2. These are selected using the Effects switch on the Interplanetary Voice. The full circuit is shown in Fig.2. It comprises just two ICs; the Holtek HT8950 and an LM386 power amplifier to drive the loudspeaker. The HT8950 requires a 2.4 to 4V supply while the LM386 can be powered from A K K A + – (CONNECTED TO CASE) the 9V supply. The electret microphone is biased from a decoupled supply that uses a 470Ω resistor from the 3.6V supply, bypassed with a 100µF capacitor. A 4.7kΩ resistor provides the electret bias current. Signal output from the electret microphone is AC coupled to the op amp within IC1. This amplifier is set up as an inverting amplifier with the 4.7kΩ resistor for the inverting input and the 39kΩ resistor providing the feedback from the op amp output. Gain is about 8.3 and signal is rolled off above 1.046kHz using a 3.9nF across the 39kΩ resistor. Below 338Hz, signal is rolled off due to the 100nF capacitor . . . and here it is inside the case. As yet, the handle has not been fitted but otherwise it is complete and ready to scare any alien! siliconchip.com.au March 2012  27 and 4.7kΩ input impedance. An internal oscillator for IC1 is formed by the 47kΩ and 100kΩ resistors at oscillator pins 13 and 12 respectively. Internal capacitance sets the frequency at 640kHz. Control inputs for IC1 are at pins 1 through to pin 3 and from pin 15 to pin 18. Only pins 3, 15, 17 and 18 are used in our circuit. The unused pins can be left open due to internal pullup resistors at each input, but we tied these high to 3.6V on the PCB. Pins 15, 17 and 18 can be momentary connected to ground using S2-S4. These set the vibrato, effects and robot functions respectively. Vibrato is toggled on or off with each press of switch S2. Pressing switch S3 cycles through the available frequency shift options for the modulator effects. Robot sound is selected with S4. It is deselected whenever there is a pressing of S3 to return to Effects mode. Vibrato can be selected as on or off in the Robot mode and Effects mode. Tying pin 3 low using LK1 sets a normal sounding voice effect. This is regardless of the selections made with S2-S4. A LED driver at pin 8 provides a variable brightness indicator of signal level received at the microphone. The LED modulates in brightness as you speak into the microphone. The processed audio signal at pin 9 is an open drain connection (from the internalP-channel output Mosfet). A suitable drain load is provided by a 510Ω resistor connected to ground. The signal is filtered using a passive MIC LEAD PASSES THROUGH HOLE S1 100k 47k MIC 470F 470F TO SPEAKER TO BATTERY HOLDER 1 47nF 5819 33nF VR1 50k LOG 39k 3.9nF 4.7k GND 10 10F 100nF D1 510 3.3k REGNAHC LK1 LED2 SHIELD WIRES CONNECT TO BODY 100F 10F ZD1 1 ROBOT S4 IC2 LM386N 10 100nF IC1 HT8950 3.3k 100nF A 3V6 + ELECTRET EFFECTS S3 MIC VOLUME 470 LED1 4.7k 1.8k 12130110 A VIBRATO S2 SPEAKER 100F 100k 10F 150 POWER VOICE Interplanetary Voice 0V +9V Fig.3: PCB component overlay, looking through the board from the non-copper side. Make sure that all components mount close down to the board surface. low pass filter comprising a 3.3kΩ resistor and 33nF capacitor. High frequency roll off is above 1.5kHz. Volume control is provided with VR1, a 50kΩ logarithmic potentiometer. The signal from the wiper of VR1 is AC coupled to IC2, the audio power amplifier, at pin 3. The inverting input of the power amplifier at pin 2 is grounded. IC2 has a gain of close to 27 as set by the 3.3kΩ resistor and series 10µF capacitor between pins 1 and 8. Power supply is bypassed with a 470µF capacitor. The separate 10µF supply bypass at pin 7 removes supply ripple from the amplifier input stages. A Zobel network comprising a 10Ω resistor and 47nF capacitor prevents amplifier instability. The output of the amplifier drives the loudspeaker via a 470µF capacitor. The capacitor pro- vides low frequency rolloff at below 42Hz for the 8Ω load. IC2 can provide about 600mW into 8Ω with a 9V supply at 3% THD. Typical distortion is less than 0.2% below 200mW. Power for the circuit is from a 9V battery using power switch, S1. Diode D1 prevents damage to the circuit with reversed supply. When supply is connected with the correct polarity, the low forward voltage drop of the Schottky diode gives extended battery life compared to when using a standard diode. Supply for IC1 is via a 3.6V zener diode (ZD1) and is fed current via a 150Ω resistor. The 3.6V supply is bypassed with a 100nF capacitor and a 100µF electrolytic capacitor. Construction Interplanetary Voice is constructed 93mm 10mm LONG M3 CSK HEAD SCREW 58mm DIAMETER PANEL 10mm LONG M3 CSK HEAD SCREWS 9V BATTERY HOLDER 25mm LONG M3 TAPPED SPACER 62mm GRILLE DISC 15mm LONG M3 TAPPED SPACERS CABLE TIES RUBBER FOAM PC BOARD ELECTRET MIC IN GROMMET 12mm LONG M3 TAPPED NYLON SPACERS 6mm LONG M3 NYLON SCREWS Fig.4: assembly details for the Interpanetary Voice. It’s tight – but it all fits! 28  Silicon Chip 32mm LONG M3 SCREW LOUDSPEAKER CEMENTED ONTO GRILLE DISC WITH EPOXY CEMENT FLARED LOUDSPEAKER PORT siliconchip.com.au on a smallish (92 x 54mm) PCB coded 08102121. The PCB is suspended within the plastic loudspeaker port and is supported at one end with the circular front panel that fits into the non-flared end of the port. The opposite end of the PCB is supported using a long standoff that is secured to the flared end of the plastic speaker port. Begin construction by checking the board for breaks in tracks or shorts between tracks or pads. If you are building the unit using a PCB, this is most unlikely – readers have commented on the outstanding quality of our boards! But if you use another board and find a problem, repair as necessary. Assembly can begin by inserting the resistors. Use the resistor colour code table as an aid to reading the resistor values. A digital multimeter can also be used to measure each value. The two diodes (D1 and ZD1) can now be installed and these must be mounted with the orientation as shown. Install the five PC stakes. Two 2-way headers are used, one for LK1 and the other as terminals to connect the microphone. Unless you want a normal sounding voice from the Interplanetary Voice, the LK1 jumper should be left off. IC1 and IC2 can be mounted using sockets although this is not necessary and the ICs can be directly soldered to the PC board. When installing the sockets (if used) and the ICs, take care to orient these correctly. Orientation is with the orientation notch or dot adjacent to pin 1 positioned as shown toward the switches. Capacitors can be mounted now. The electrolytic types must be oriented with the shown polarity. Keep the height of the electrolytic capacitors below 14mm overall above the PCB to provide clearance for the battery holder that mounts onto 15mm spacers over the PCB. Cut the potentiometer shaft to 12mm long and remove the locating spigot at the side of body adjacent to the mounting thread. This is easily snapped off with pliers. Install VR1 and the switches S1-S4. VR1 should be connected (soldered) to the GND PC stake using a short length of tinned copper wire. An offcut from a resistor lead will be suitable. It is usually necessary to scrape away some of the coating on the pot body before soldering to the back of the pot, otherwise the solder siliconchip.com.au Parts List – Interplanetary Voice 1 PCB, coded, 08102121, 92 x 54mm (available from SILICON CHIP for $15 +p&p) 1 panel label 58mm in diameter 1 flared speaker box port 58mm diameter x 120mm long 1 57mm diameter 8Ω loudspeaker 1 electret microphone insert 9.5mm diameter 1 62mm diameter x 1mm aluminium or fibreglass disc for speaker grille 1 58mm diameter x 1mm aluminium or fibreglass disc for front panel 1 rubber grommet with 9.5mm ID hole 1 9V PCB mount battery holder 1 9V Alkaline battery 1 50k 16mm log pot (VR1) 1 potentiometer knob 1 SPDT PCB mount toggle switch (S1) (Altronics S1421 or equivalent) 3 right angle tactile pushbutton PCB switches with 3.5mm actuator (S2-S4) (Jaycar SP-0606 or equivalent) 1 DIL8 IC socket (optional) 1 DIL18 IC socket (optional) 2 3mm LED bezels 3 15mm M3 tapped spacers 2 12mm M3 tapped spacers (or 1 25mm M3 tapped spacer cut to 2 x 12mm) 1 25mm M3 tapped spacer 1 M3 x 32mm screw 1 M3 x 10mm pan head or countersunk screw 3 M3 x 6mm screws 3 M3 x 6mm countersunk screws 2 2-way pin headers (2.54mm spacing) 1 jumper shunt 2 100mm cable ties 1 20-30mm diameter piece of thin rubber foam (eg, opened out earphone pads) 5 PC stakes 1 100mm length of single core screened cable 1 50mm length of light duty figure-8 wire 1 50mm length of red hookup wire 1 50mm length of black hookup wire Semiconductors 1 HT8950 (18-DIP version) Voice Modulator (IC1) (Do not use the HT8950A since this has 16 pins and different pinouts to the HT8950) (Available from www.littlebirdelectronics.com) 1 LM386N Audio amplifier (IC2) 1 3.6V 400mW zener diode (ZD1) 1 1N5819 1A Schottky diode (D1) 1 3mm red LED (LED1) 1 3mm green LED (LED2) Capacitors 2 470µF 16V PC electrolytic 2 100µF 16V PC electrolytic 3 10µF 16V PC electrolytic 3 100nF MKT polyester 1 47nF MKT polyester 1 33nF MKT polyester 1 3.9nF MKT polyester Resistors 2 100kΩ 1 47kΩ 1 39kΩ 2 4.7kΩ 2 3.3kΩ 1 1.8kΩ 1 510Ω 1 470Ω 1 150Ω 2 10Ω Miscellaneous Silicone sealant, solder, heatshrink tubing Handle 1 90 x 110 x 19mm solid timber (shaped for a handle) 2 cheese head wood screws 12mm long March 2012  29 (Above): a view of the back of the PCB, showing how it and the other hardware is assembled before insertion in the “case”. At right is a close-up of the front end of the PCB with the various “front panel” controls. will not adhere. LED1 and LED2 mount horizontally but at a height of 13mm above the PCB. But firstly, bend the leads at 10mm back from the base of each LEDs at right angles making sure the anode lead is oriented toward S1 as shown on the overlay diagram. The panel label for this project can be downloaded from the SILICON CHIPwebsite (siliconchip.com.au). This file also contains a drilling guide for both the control panel and the loudspeaker grille. Go to the download section and select the month and year of publication. When downloaded, you can print the drilling guide onto paper. Drill the panels as shown on the drill guide. Also remove the swarf from the edges of the holes with a larger drill or countersinking drill. The front panel label can be printed onto sticky backed photo paper or onto plastic film. When using clear plastic film (overhead projector film) you can print the label as a mirror image so that the ink is behind the film when placed onto the panel. Once the ink is dry, cut the label to size. The paper or plastic film is affixed to the panel using an even smear of neutral-cure silicone. Holes in the label can be cut with a sharp hobby knife or a leather punch. Installation Fig.4 shows the assembly details for the Interplanetary Voice. The electret microphone is mounted inside a rubber grommet attached to the front panel below the PCB. A length of shielded cable is used to connect the microphone to the PCB. The wire passes through a hole near LED2 on the PCB. Make sure the earth side of the electret connects to the shield. The shield at other end of the shielded cable connects to the earth pin on the PCB as shown for the electret wiring. The 9V battery holder is secured to the PCB using 15mm tapped standoffs. The three mounting holes in the battery holder are drilled out to 3mm to accommodate the M3 screws. In doing this the original underside bushes at these battery-holder mounting points are also removed and cleaned up with a larger drill. This will allow the battery holder to sit closer to the PCB. Bend the connecting pins on the holder backwards under the battery holder and solder leads to connect to the supply PC stakes on the PCB. M3 machine screws secure the standoffs to the PCB, while M3 countersunk screws are used for the battery holder. The rear mounting point on the PCB utilises two 12mm and one 25mm long standoff. Cutting a 25mm standoff in half can make up the 12mm standoffs required (or use separate 12mm standoffs). These are secured to the PCB with an M3 x 32mm screw. The screw is first screwed into a 12mm standoff and the remaining screw thread section is inserted into the PCB from the underside and then screwed into the second 12mm standoff. The 25mm standoff then is screwed onto the last remainder of screw thread. The 25mm standoff is secured to the speaker port with an M3 x 10mm screw. The front panel attaches to the PCB with the potentiometer nut. The LEDs are secured with 3mm LED bezels while switches S1-S4 simply protrude through the panel holes. The speaker is glued to the grille disc. We used silicone sealant although many alternative types of glue can be used instead. When the glue or sealant is dry, solder the figure-8 wire to the speaker terminals and PC stakes on the PCB. The speaker is supported Resistor Colour Codes q q q q q q q q q q No. 2 1 1 2 2 1 1 1 1 2 30  Silicon Chip Value 100kΩ 47kΩ 39kΩ 4.7kΩ 3.3kΩ 1.8kΩ 510Ω 470Ω 150Ω 10Ω 4-Band Code (1%) brown black yellow brown yellow violet orange brown orange white orange brown yellow violet red brown orange orange red brown brown grey red brown green brown brown brown yellow violet brown brown brown green brown brown brown black black brown 5-Band Code (1%) brown black black orange brown yellow violet black red brown orange white black red brown yellow violet black brown brown orange orange black brown brown brown grey black brown brown green brown black black brown yellow violet black black brown brown green black black brown brown black black gold brown siliconchip.com.au using cable ties that wrap through the speaker frame and around the standoffs. A 30mm diameter piece of thin rubber foam is affixed to the back of the speaker magnet to help keep the speaker in place. The speaker should be positioned so that it is centred within the speaker port flare. This is when assembled into the speaker port with the 25mm standoff located up against the top inside of the speaker port. A 3mm hole is required in the top of the speaker port flare for the M3 countersunk screw to secure the 25mm standoff. This is located 93mm from the non-flared port end as shown in Fig.4. Note that a series of holes should be drilled into the speaker port to prevent the port acting as a tuned pipe. Without the holes, there will be sufficient resonance for feedback from the speaker to the microphon, causing a howling noise. This would occur with only moderate volume settings with at least two of the effects selections on the Interplanetary Voice. To allow a reasonable volume without feedback, we drilled a series of holes in the port. The holes are arranged as a row of eight 5mm diameter holes distributed along the length of the port and repeated at 45-degree intervals around the diameter. That’s 64 holes in total. A handle was fashioned from an off cut piece of timber and secured to the underside of the speaker port with two wood screws. The screw heads are set raised above the timber by the 2mm of the speaker port thickness. The shape of the handle is not critical so long as it is comfortable to hold. The handle can be finished with black paint or stain. Two holes are drilled in the underside of the speaker port, large enough to allow the head of each screw to insert. Then slots are filed from each hole toward the flared end just wide enough for the screw but not for the screw head. Inserting the two screw heads into the holes and pushing forward so that the screws engage the slots attaches the handle. Removal is the reverse procedure pulling back the handle so the screw heads can be removed from the holes. The handle will need to be removed both to insert and to remove the Interplanetary Voice assembly within the speaker port. Testing Insert the 9V battery and switch on the Interplanetary Voice with the power switch. Power LED (LED1) should light. If not check the polarity of the LED. Measure the voltage using a multimeter between the GND PC stake behind VR1 and the cathode of ZD1. This should be a voltage that is around 3.6V although anywhere between 3.3 and 3.9V is OK. Speaking into the microphone should produce sound from the loudspeaker with suitable level set by the volume control. LED2 should vary in brightness with voice volume. When power is first applied to the Interplanetary Voice, the voice effect is set for Robot. Pressing the Effect switch will change the sound from Robot and you can cycle through seven different effects with each switch press. Robot voice is selected at any time again with the Robot switch. Pressing the Vibrato switch will add vibrato to the sound and pressing the Vibrato switch again will deselect vibrato. Adjust the volume control for the best effect from the Interplanetary Voice. Note that excessive volume may ultimately produce feedback between the speaker and microphone, particularly with the Robot voice selection. Generally the volume is best adjusted to prevent feedback but for added Power + + Level + + + + Vibrato Effects Robot + Volume + Fig.5: here’s the “front panel” label which also serves as a drilling template. This and other diagrams can be downloaded from siliconchip.com.au effects, set the volume just at the threshold of continuous feedback. This tends to make the voice ring for a short period. Quiescent current consumption for Interplanetary Voice is about 40mA. More current is drawn from the battery as the Interplanetary Voice delivers sound. So we recommended you switch off power after use because the 9V battery won’t last long otherwise. Note that if you are not imitating a metallic voice sound, then LK1 can be shorted with a jumper shunt for a normal voice sound from Interplanetary Voice. That will allow you to speak to humans using their own style of voice. Alternatively, for normal voice, the Interplanetary Voice can be dispensed with altogether and using your vocal cords totally unaided. But doing this you run the risk of being discovered as human rather SC than alien. Capacitor Codes Value µF Value IEC Code EIA Code 100nF 0.1µF   100n 104 47nF 0.047µF   47n 473 33nF 0.033µF  33n 333 3.9nF 0.0039µF 3n9 392 siliconchip.com.au Here’s the handle we made – it mates with the two “keyholes” in the Interplanetary Voice case. Note also the drilling required in the case. March 2012  31