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Assembly and Operating Instructions for HiViz.com Kits

 

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Assembly Instructions for the Multi-Trigger 2 Kit (MT2, Build 2)

 

Assembly instructions for other kits

 

These instructions are for Build 2 of the Multi-Trigger 2. Build 2 was sold from May 15, 2012 to December 19, 2012. If you're not sure what build you have, click here to identify the PC board.

 

Contents

 

The assembly instructions below are designed to be used online for greatest benefit. In that mode, the links work and images can be enlarged to see detail. If you prefer working from printed instructions, here are pdf files. Note that the links in these files don't work, and enlarged images aren't available. PDFs: Parts list / Building the control box / Preparing the cables / PC2 trigger cable / Operating manual

 

Building the control box

What you need

Parts guide (opens in new tab or window)

A helpful reference (includes circuit schematic)

Soldering the fixed-value resistors to the PCB

Soldering the IC sockets to the PCB

Soldering the capacitors to the PCB

Soldering the semiconductors to the PCB

Drilling holes in the project box lid

Adding the components to the project box lid

Wiring the box lid

Soldering and connecting to the PCB

 

Preparing the cables (opens in new tab or window)

 

If you're adding the Output Extender Kit to an existing Multi-Trigger 2, see these instructions.

 

About the images: Clicking on any image will open a larger version on top of the page. If you prefer to have the larger images open in a different tab or window, right click on the image and make the appropriate selection.

 

What you need

 

PCB for Multi-Trigger 2These instructions show how to prepare and use the PC board and project box enclosure for the Multi-Trigger 2. The MT2 comes complete with all the parts needed for assembly of a working Multi-Trigger on a PC board enclosed in a project box. Also included are the parts for the sensor cables.

 

The PC board is shown to the right. You'll see that the locations for the components are labeled with symbols like R5, C1, etc. This makes it easy to find where to place the components.

 

You'll need to solder the components to the back (non-printed side) of the PCB. We'll provide guidelines for getting good solder joints, but we recommend that you have previous experience soldering on a PC board. With soldering, you can't make changes easily like you can with a breadboard. If you solder something in the wrong place, repair can be time-consuming.

 

Having the right tools will make the job easier. You'll need to provide your own. Here's what we recommend.

 

For soldering

  1. 15-30 W soldering iron (with a new or pointed tip) and solder
  2. Wire stripper (photo below)

  3. A small diagonal cutter (photo below) makes it easy to trim the legs of the components after you solder them to the PCB, but other kinds of snipping tools such as scissors may work.

  4. Needle-nose pliers (photo below) make it easier to handle small components, especially if you have big fingers.

  5. A heat sink (photos below) protects heat-sensitive components while soldering.

  6. A desoldering tool (photos below) helps in clearing solder from a hole. The cylindrical type works better than the bulb.

  7. A magnifying glass is used to inspect solder joints.

  8. A lighter or matches to shrink heat-shrink tubing

    Wire cutters and stripper

    Small diagonal cutter

    diagonal cutter

    Needle-nose pliers

    needle-nose pliers

    Heat sinks

    heat sink clip heat sink clip

    Desoldering tools

    desoldering tool desoldering bulb

     

Be sure to solder in a well-ventilated area. Keep the tip of your soldering iron clean by wiping it against a wet sponge. Once the tip is clean, touch a bit of solder to the tip to tin it and improve heat conductivity. Inspect your solder joints to see if the solder flowed well to make good electrical contact. If it looks like the solder formed a bead, that's likely a bad joint and will not conduct. Reheat to flow the solder.

 

For the project box

  1. Drill motor and bits to drill holes in the project box lid. Bit sizes are 3/32", 1/8", 1/4", 9/32", and 5/16". (For metric equivalents in millimeters, multiply by 25.4.) You can substitute a 1/8" bit for the 3/32" one. You can get by without the 9/32" bit by drilling a 1/4" hole and filing it larger.
  2. Hammer, punch (or nail), small round file
  3. Wrenches or sockets to tighten components onto the project box

Aids to troubleshooting

 

If you need to troubleshoot problems with the circuit, it will help to have at least some basic skills in building and testing electrical circuits. These involve such things as testing for polarity and continuity, for examining solder connections, and for measuring voltages. In addition to such knowledge and exerience, having a continuity checker or multimeter and clip wires may be helpful.

 

Parts guide

 

Click here for a detailed, illustrated list of all the parts you'll need. You can use this list to identify the parts and make sure you have them all.

 

A helpful reference

 

It will be helpful to print this pdf document for reference while you work. There are lists of component placements and jumper wire connections. For those who like to use circuit schematics, there's a complete schematic of the circuit.

 

Soldering the fixed-value resistors to the PCB

 

10-ohm resistorIf you don't have your soldering iron heated up, do that now, because you'll be soldering before long. You'll be doing some detailed soldering work, so an iron with a good tip will make it easier. Resistors R1 to R4 will be soldered to the lid of the project box, so we won't do those yet. R5 is a jumper wire, so we'll start with R6, a 10-ohm resistor that will be soldered to the PCB. See the photo to the right, and refer to the Parts Guide as needed for parts to come. The resistors are identified by the sequence of 3 colored bands, read from left-to-right. (The 4th, gold band indicates that the actual value of the resistance is plus or minus 5% of the value given by the color code.) For the resistor shown to the right, the bands are brown-black-black.

  1. Insert the legs of resistor R6 over the rectangular space labeled R6 on the PCB. See Figure 1. (Click on it for a closeup view.) You can flip the resistor either way in the holes; the orientation doesn't matter for resistors, since resistors work the same no matter which way current flows in them.

  2. Push the resistor in until it's flush with the surface of the PCB. Then flip the PCB over. Figure 2 shows the legs protruding from the back of the board.

  3. Next you'll solder. Tin the tip of the soldering iron by melting some solder on it. Then bring the point and the solder down to one of the holes where the resistor protrudes as in Figure 3. Melt some solder around the base; it doesn't take much. The solder should flow down into the hole around the leg of the resistor to make a good electrical joint. Now solder the other leg.

  4. Snip off the legs of the resistor. The completed solder joints are shown in Figure 4 from the underside and in Figure 5 from the top. If you don't see that solder melted through to the upper side, it's probably a good idea to melt some more solder into the hole from the back of the board.

  5. Something to be aware of before you do any more soldering is that there are two kinds of holes on the board: solder holes and via holes. The solder holes are for the component legs. The via holes, which are smaller than the solder holes, are places where there are connections between the upper and lower conducting layers of the board. To see what we mean, click on Figure 6, which shows a small section of the board. The via holes have been circled in yellow. Don't try to solder components into via holes. If, however, you get solder in a via hole, don't worry about it.

  6. In order to get greatest sensitivity from the sound trigger, solder a jumper wire into the location R5. (If you have an application for which you need to significantly reduce sensitivity, an extra 1000-ohm resistor is provided for R5.) Cut a 1" jumper wire, and strip and bend over the ends as shown in Figure 7.

  7. Now solder the jumper wire into place. The result is shown in Figure 8.

  8. Solder the remaining resistors R7 to R15 onto the board. The result is shown in Figure 9.

  9. If you're also assembling the optional Output Extender Kit, solder resistors R16 and R17 now. These are 100-ohm resistors.

inserting R6 R1 from back of PCB Soldering a leg of the resistor R6 from back of PCB
Figure 1. Resistor R6 inserted into dedicated space on PCB Figure 2. Legs of resistor R6 protruding from back of PCB Figure 3. Soldering a leg of the resistor Figure 4. Completed solder joints from the underside
R6 from top of PCB via holes Jumper wire ready to insert into R5 Jumper wire ready Figure 8. Jumper wire soldered to PCB
Figure 5. Completed solder joints from the top Figure 6. Via holes (circled in yellow) and solder holes Figure 7. Jumper wire ready to insert into R5 Figure 8. Jumper wire soldered to PCB
board with all resistors      
Figure 9. PC board with fixed-value resistors mounted (R16 and R17 would only be added if you're installing the Output Extender kit.)      

 

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Soldering the IC sockets to the PCB

 

The three 8-pin and one 14-pin IC sockets will be used to seat the four ICs. The latter won't be added to the sockets until later, since the ICs can potentially be damaged by heat.

  1. See Figure 10, which shows one of the 8-pin sockets next to the location where it will be mounted. Note that the socket has a notch on one end. You'll line this notch up with the one on the PCB when you seat the socket into the board.

  2. Place the 8 pins of the socket into the corresponding holes on the PCB as shown in Figure 11.

  3. Turn the board over and bend the pins down to the side to hold the socket in place as shown in Figure 12.

  4. Solder the 8 pins to the board. The finished result is shown in Figure 13. Check with a magnifying glass to make sure there are no solder bridges or hairs between pins. If so, remove them by running the tip of the soldering iron between the pin.

  5. Now solder the 14-pin socket and the other two 8-pin sockets to the board similar. Remember to line up the notches. FIgure 15 in the next section shows the board with all sockets soldered into place.

8-pin socket notch seating the 8-pin socket Crimping the 8-pin socket 8-pin socket soldered to PCB
Figure 10. Notches on the socket and the PCB Figure 11. 8-pin socket seated on PCB Figure 12. Crimping the pins of the 8-pin socket Figure 13. 8-pin socket soldered to PCB

 

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Soldering the capacitors to the PCB

 

There are two kinds of capacitors, ceramic and electrolytic. We'll start with a ceramic capacitor. There are 8 of these; they all have a disc shape and are orange or yellow in color. A number on the disc identifies the capacitor. The capacitor in Figure 14, for example, has the number 472. From the Parts Guide, you can determine that this is a 0.0047-μf capacitor.

  1. Refer to Parts Guide to see which capacitors are associated with C1, C2, etc. on the PCB. C1 is a 0.0047-μf capacitor. Figure 15 shows the capacitor lying over the corresponding location on the PCB. Slip C1 into the holes now as shown in Figure 16. Ceramic capacitors, like resistors, are non-polar. So it doesn't matter if you flip them one way or the other other in the solder holes. The legs should extend about 1/8" from the top side of the board. Bend the legs over on the back to keep the capacitor from slipping out when you turn the board over. The soldered capacitor is shown in Figure 17.

  2. Go ahead and solder the C2 capacitor similar to how you did C1. This is another ceramic capacitor and has a value of 0.047 μf. It's marked on the case with the number 473.

  3. Next you'll solder an electrolytic capacitor. There are 6 of these. The electrolytical capacitors have cylindrical metal cases with the value of the capacitance printed on them. These capacitors are polar; that is, they have a positive and negative side. Therefore, there's only one way to mount them in the PCB. See the photo of two sides of a 0.47-μf capacitor in Figure 18. (This is capacitor C3.) The shorter leg is negative and corresponds with the light-colored strip on the case. Now look at Figure 19, which shows the C3 capacitor lying over its mounting holes on the PCB. Note that the location of the hole for the positive leg is marked on the PCB. Go ahead and insert the legs in the holes (positive leg to the right in the photo). Remember not to let the legs for this and all the other capacitors extend more than 1/8" from the top of the board. Otherwise, when you mount the PCB to the project lid later, you may not be able to fit the lid snugly onto the box. Go ahead now and solder the legs of C3 to the board. Figure 20 shows the soldered capacitor.

  4. Go ahead now and solder the remaining capacitors to the board. Figure 21 shows all capacitors soldered to the board.

  5. If you haven't snipped off the legs of the capacitors protruding from the back, do that now. Snip them at the solder joint. You don't want to have any legs that can be bent over and touch other legs to create short circuits.

0.0047-uf capacitor C1 capacitor next to mounting holes C1 slipped into holes on PCB C1 soldered to PCB
Figure 14. 0.0047-μf ceramic capacitor Figure 15. C1 capacitor next to mounting holes Figure 16. C1 slipped into holes on PCB Figure 17. C1 soldered to PCB
Two views of a 0.47-μf electrolytic capacitor C3 capacitor next to mounting holes C3 capacitor soldered to the board Board with all resistors, capacitors, and sockets
Figure 18. Two views of a 0.47-μf electrolytic capacitor Figure 19. C3 capacitor next to mounting holes Figure 20. C3 capacitor soldered to the board Figure 21. Board with all resistors, capacitors, and sockets

 

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Soldering the semiconductors to the PCB

  1. There are two semiconductors called silicon-controlled rectifiers (SCR). You'll solder the larger of the two SCRs first. It has TYN408G printed on the front. Insert the SCR into the board into the location labeled SCR1 on the PCB. Note that the metallic side of the SCR faces to to the outside of the board. Figure 22 shows the SCR from the back. A heat sink has been clipped to the legs to help protect the component from excessive heat when soldering. Go ahead and solder the three legs to the board. Afterwards, inspect the back of the board closely for any solder bridges.

  2. Now insert the smaller of the two SCRs, labeled EC103D, into the location labeled SCR2 on the PCB. Note that the flat side of the component faces toward the inside of the board as shown in Figure 23. Go ahead and solder the legs on the underside and inspect for solder bridges. Figure 24 shows SCR2 soldered to the board from the opposite view as Figure 23.

  3. To finish, snip the legs of the SCRs extending under the board.

  4. If you're assembling the Output Extender Kit, go ahead now and solder SCR3 and SCR4 to board in the indicated locations. These are both EC103Ds. The completed PCB (before insertion of the ICs) is shown in Figure 25. Note that the SCRs for the Output Extender Kit are shown.

Getting ready to solder SCR1 to the PCB Seating SCR2 on the PCB SCR2 soldered to the PCB Completed PCB
Figure 22. Getting ready to solder SCR1 to the PCB Figure 23. Seating SCR2 on the PCB Figure 24. SCR2 soldered to the PCB Figure 25. Completed PCB (SCR3 and SCR4 for the optional Output Extender Kit are shown.)

 

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Drilling holes in the project box lid

  1. The template is sized to fit snugly within the underside of the project box lid (that is, on the interior side of the box). Position the template inside the lid as shown in Figure 26. Then use a nail or punch to mark the positions of the centers of the holes to be drilled.

  2. Remove the template and drill the holes. We recommend drilling small pilot holes first, for example, 3/32" or 1/8". The plastic has a tendency to grab the bit, so hold the plastic securely. We've found that spade bits work best for drilling the 1/4" and 5/16" holes. If you don't have a 9/32" bit, you can use 1/4" and then file the hole to a larger diameter for the pushbutton. The hole size is most critical for the LED holders. If the hole is slightly small, it will take a lot of force to snap the LEDs into the holder. If the hole is slightly large, the LED will wobble in holder; however, this won't affect its function.

  3. Use a round file to clean up any burrs around the holes. The lid with holes drilled is shown from underneath (Figure 27) and from above (Figure 28).
template in underside of project box lid Project box lid from underside after holes drilled Top of project box lid after holes drilled Top of project box lid after holes drilled
Figure 26. Template placed in underside of project box lid Figure 27. Underside of project box lid after holes drilled Figure 28. Top of project box lid after holes drilled

Figure 28b. Template for labels, courtesy of M. Mazin (Click on the image for a full-size version that can be printed.)

  1. Your kit includes stick-on label strips for the top of the lid to identify the functions of the jacks, LEDs, switches, and knobs. It's not necessary to put these on until after the components are added to the lid. To see what the lid will look like with the label strips added, scroll down to Figure 36. If you prefer to have a single sheet of labels to cover the entire lid, see Figure 28b. This template is provided courtesy of Muhammad Mazin, who modeled the template after one created by Erwin Stok for the previous version of the Multi-Trigger enclosure. Click on Figure 28b for a full-size jpg. If you prefer to use this or your own template rather than the stick-on labels, now would be the time to print the template on self-adhesive paper and affix it to the lid. Then you can cut out the holes for the components before mounting them.

Adding the components to the project box lid

  1. LED holderWe recommend adding the three red LEDs and their mounts first, since people tend to have difficulty getting the holders to snap into place. The LED mounts have two parts, which we will call the collar and the ring. (See photo to the right.) The collar is first slipped into a hole on the project box from the top side toward the interior of the box and snapped into place. Then the LED is pushed up into the collar from below. We recommend orienting the LEDs so that the shorter of the two legs is toward the inside of the box as shown in Figure 29. It's important to get the LEDs to snap into the collars. It may take quite a bit of extra force to push it the last bit of the way. You'll know it's in when it snaps. If you don't push the LED in all the way, it will be loose in the collar. Note in Figure 29 how the bottom of the red case sits down inside the collar. Also see Figure 30 which shows the LEDs from the top of the box. Note how far they extend above the collar. If you find it too difficult to snap the LED into the holder, remove the LED and the collar and file the hole slightly. The tightness of fit of the LED in the collar is very sensitive to the size of the hole.)

  2. Once you have the LEDs snapped in, push the rings over the collars from below. See Figure 31.

LEDs inserted into collars from below LEDs from above Completed LED holder assembly  from below
Figure 29. LEDs inserted into collars from below Figure 30. LEDs from top of project box Figure 31. Completed LED holder assembly from below  

 

For the remaining components, we don't provide step-by-step photos. The completed assembly of all components on the project box lid is shown in Figures 32 and 33 from below and above, respectively.

  1. Remove the nut from a 3.5mm jack, insert the jack through the box lid from below, and screw the nut back on. Needle-nose pliers can be helpful in tightening the small, round nuts. There are five of these 3.5mm jacks to mount. The three black ones are stereo jacks; the other two are mono jacks.

  2. Remove the nut from the 9VDC input jack (lower right corner in Figure 32), insert the jack through the box lid from below, and screw the nut back on. You can use a wrench on this nut.

  3. Remove the nut and lock washer from the pushbutton, insert the pushbutton through the box lid from below, slip on the washer and screw the nut back on.

  4. The five switches have a retaining ring with a key tab, a washer, and a nut. Remove all three and then insert the switch from below. Orient the slot on the threads to be on the same side as the 3/32" key hole. Then slip the retaining ring on so that the key tab slips into the 3/32" hole. Slip on the washer and nut and tighten.

  5. The potentiometers also have key tabs but these are on the body of the pot. Remove the washer and nut from a pot, slip it in from below and orient it so that the key tab passes up through the 1/8" key hole. Then put on the washer and nut and tighten. The positions of the 5 pots P1-P5 are indicated by the yellow text overlay on the photo. (P1 = 10 kΩ; P2 = 10 kΩ; P3 = 100 kΩ; P4 = 1MΩ; P5 = 100 kΩ)

  6. You may wish to go ahead and put the labels on the box lid now. Do this before putting the knobs on the pots. You can make the task a bit less tedious by keeping some of the labels in continuous, uncut strips. For example, "MIC-INPUT-PG   OFF-DEL/10-ON  TIMEOUT", "SND-SENS-PG", and "FINE-DELAY-COARSE" can be continuous strips. See Figure 34.

  7. Now you can put the knobs on the pots. Turn all the pots counterclockwise as far as they will go. Orient the pointers so that they point as shown in Figure 35 and tighten the set screws. Figure 36 shows all the knobs mounted and turned to their halfway settings.

Besides the four mounting holes on the outside corners of the lid, there are four other holes that haven't been used yet. These holes are for standoffs that will support the PC board. You can mount the standoffs now or wait until later so that they won't get in the way while you're adding wires to the lid.

 

Components mounted on project box lid (view of underside) Components mounted on project box lid (view of the top) Box lid with labels 0 setting of knob
Figure 32. Components mounted on project box lid (view of underside) Figure 33. Components mounted on project box lid (view of the top) Figure 34. Box lid with stick-on labels Figure 35. Zero setting of a knob
Box lid with knobs      
Figure 36. Box lid with knobs      

 

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Wiring the box lid

 

Some of the components on the box lid will be hardwired to each other. Make connections for now but don't do any soldering yet.

  1. There are four resistors that are connected between components on the lid. We'll start with the 1-kΩ resistor labeled R1 in the Parts List. See Figure 37 for the placement of the resistor. Connect it from the lug on the side of the microphone jack (MIC) to the shorter leg of LED1. You'll need to clip the legs of the resistor to make it fit. Something to help in spiraling the resistor legs around the LED leg is to wrap the resistor leg around a small nail first as shown in Figure 38.

1-kΩ resistor connected on box lid Wire wrapping Resistors R1-R4 connected to box lid
Figure 37. 1-kΩ resistor connected on box lid Figure 38. Wrapping a resistor leg around a nail Figure 39. Resistors R1-R4 connected to box lid
  1. The connections of resistors R2 to R4 are shown in Figure 39 above and listed in the table below. A photo of the stereo jack is provided to help identify the lugs.
  Value Connection 1 Connection 2 Lugs of 3.5 PG jack
R2 100 Ω right lug of P4 center lug of P3 Solder lugs of 3.5mm stereo jack (inverted)
R3 1 kΩ center lug of P5 longer leg of LED2
R4 470 Ω

lug 1 of photogate jack, PG

(see photo to right)

right lug of P1

 

  1. Use the white hookup wire to make all the ground connections. The lengths of wire provided in the kit are based on using the same colors as given in these instructions. You'll be clipping off lengths of wire and making the connections shown in Figure 40 below. A list of connections is provided in the table below. See Figure 41 for a close up of the connection to the 9VDC jack.

A note about the switches: While all the switches are of the same type, three of them will be used as SPST (on-off) switches and two as SPDT (double throw). The first three are labeled SPST1, SPST2, and SPST3. The other two switches are SPDT1, which selects between the sound trigger or photogate input to the delay unit, and SPDT2, which selects between two possible delay ranges.

 

X to Y X Y Lugs of EXT jack Lugs of 9VDC jack
A to B

lug 2 of 9VDC jack

(see photo to right)

center lug of SPST1 Solder lugs of 3.5mm monoo jack (inverted) Solder lugs of the 9VDC jack
C to D right lug of SPST1 shorter leg of LED3
D to E shorter leg of LED3 center lug of P2
E to F center lug of P2

lug 1 of external input jack, EXT

(see photo to right)

F to G lug 1 of EXT right lug of P1
G to H right lug of P1 either lug on the pushbutton switch, PB
E to J center lug of P2

lug 1 of the microphone jack, MIC

(see photo to right)

 

Ground (white) wires added Connection of ground wire to 9VDC jack +9V (red) wires added Connection of ground wire to 9VDC jack
Figure 40. Ground (white) wires added Figure 41. Connection of ground wire to 9VDC jack Figure 42. +9V (red) wires added Figure 43. Connections to 9VDC jack
  1. Use the red wire to make all the +9V connections. Refer to Figure 42 above and the table below for the connections. Also see Figure 43 for a close up of the connections to the 9VDC jack.
X to Y X Y Lugs of PG jack Lugs of 9VDC jack
A to B lug 3 of 9VDC jack lug 3 of PG jack Solder lugs of 3.5mm stereo jack (inverted) Solder lugs of the 9VDC jack
B to C lug 3 of PG jack longer leg of LED1
C to D longer leg of LED1 longer leg of LED2
D to E longer leg of LED2 center lug of P4
  1. Now for the blue wires. Refer to Figure 44 and the table below for the connections.
X to Y X Y Lugs of DO,IO jacks Lugs of EXT jack
A to B center lug of SPDT1 lug 2 of EXT jack Solder lugs of 3.5mm stereo jack (inverted) Solder lugs of 3.5mm monoo jack (inverted)
C to D center lug of SPDT2 right lug of P3
E to F lug 2 of delayed output (DO) jack right lug of SPST3
G to H lug 2 of instant output (IO) jack right lug of SPST2
Blue wires added Yellow wires added Connections to the external input jack  
Figure 44. Blue wires added Figure 45. Yellow wires added Figure 46. Connections to the external input jack  
  1. Finally there are some yellow wires to connect to complete the connections between components on the box lid. Refer to Figure 45 above and the table below for the connections. See Figure 46 for a close up of connections to the external input jack.
X to Y X Y Lugs of DO,IO jack Lugs of EXT jack
A to B lug 1 of DO jack center lug of SPST3 Solder lugs of 3.5mm stereo jack (inverted) Solder lugs of 3.5mm monoo jack (inverted)
C to D lug 1 of IO jack center lug of SPST2
E to F lug 3 of EXT jack remaining free lug of pushbutton PB

 

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Soldering and connecting to the PCB

 

It's about time to start soldering. Here are some important tips about soldering in addition to those given previously.

 

Using a heat sinkSoldering to the legs of the LEDs: These components can be damaged by excessive heat; therefore, it's a good idea to clip a heat sink to the leg when soldering. This technique is shown in the photo to the right for LED3. Note also that the wrapped wires to be soldered are pushed down to the part of the leg close to the red case of the LED. This is important, because the PCB will eventually be seated above the components on the board. It must be possible to trim down the legs of the LEDs so that they don't come in contact with the PCB.

 

Soldering the switches: Don't hold the soldering iron on the switch lugs too long, as the plastic can melt and break the internal contacts.

 

Soldering the 3.5mm jacks: The lugs on these jacks bend and break easily. Go easy on them.

 

Soldering the 9VDC jack: Be very careful not to get too much solder on the lugs so that the solder drips down, particularly on the center lug. If the solder drips down, it can create a dead short between the positive and negative power terminals.

 

About cold solder joints: If you don't heat the metal before soldering the wire, the solder may not bond with it and you can get an open circuit. You can't necessarily tell by looking that you have a cold solder joint. The best approach is prevention by using good soldering techniques. Hold the tip of the soldering iron flat against the metal surface that you're soldering to. Touch the solder to the metal nearby rather than to the soldering iron. When the metal is hot enough, the solder will flow. Flow enough solder on the connection to fill the hole and cover the connection, but don't leave the soldering iron on the metal any longer than it takes to flow the solder. Examine the connection under a magnifying glass. If the solder beaded up, you may not have a good connection.

  1. Figure 47 below shows the junctions circled in green that can be soldered now. If a junction isn't circled, don't solder it yet, because additional wires need to be added to jump to the PCB.

Junctions to solder on the box lid

Connection points for external wires

 

Figure 47. Junctions to solder on the box lid

Figure 48. Connection points for external wires

 

 
  1. Figure 48 above shows with reference numbers circled in yellow where wires will be connected to jump to the PC board. Before soldering the connections, we recommend cutting the wires to the lengths given in the tables below. The lengths are sized to be long enough to reach the corresponding holes on the PCB but not so long as to add unnecessarily to the mass of wires that will have to be compressed when the PCB is finally bolted down. Note that number 16 doesn't appear in the table below even though it corresponds to a hole on the PCB. That's because hole 16 is an alternate ground hole that isn't needed, since hole 1 is also a ground connection.
Lengths in inches Lengths in centimeters
No. Color Length No. Color Length
1 blue 2.0 11 green 2.0
2 yellow 2.0 12 yellow 1.5
3 blue 3.0 13 yellow 1.5
4 yellow 2.0 14 yellow 2.5
5 blue 3.5 15 green 2.5
6 red 3.0 17 green 3.0
7 red 2.5 18 red 2.0
8 green 1.5 19 blue 2.0
9 blue 2.0 20 green 1.5
10 yellow 3.0 21 green 1.5
No. Color Length No. Color Length
1 blue 5.1 11 green 5.1
2 yellow 5.1 12 yellow 3.8
3 blue 7.6 13 yellow 3.8
4 yellow 5.1 14 yellow 6.4
5 blue 8.9 15 green 6.4
6 red 7.6 17 green 7.6
7 red 6.4 18 red 5.1
8 green 3.8 19 blue 5.1
9 blue 5.1 20 green 3.8
10 yellow 7.6 21 green 3.8
  1. Now is a good time to add the standoffs. Use 4 of the 1/4" long 4-40 bolts to bolt the 4 standoffs to the box lid. Insert the bolts from the top of the box. Figure 49 below shows the standoffs circled in green.

  2. Figure 50 shows the PC board as it will be oriented on the standoffs. This photo is provided for reference at this point. When soldering the wires in the next step, it's easier to move the PC board to the side out of the way.
  3. Figure 51 shows all the jumper wires soldered to the lid. The legs of the LEDs have been clipped above the solder joints. The stick-on numbers corresponding to the numbers in Figure 49 have been added to the wires for ease of identification. Note that lug 1 of the 9VDC jack is circled in green and labeled B(-) at the lower right in Figure 51. You'll solder the black wire of the battery holder to this lug in a later step.

Standoffs shown circled in green

PCB orientation on lid

Jumper wires connected to box lid PCB soldered to the box lid

Figure 49. Standoffs shown circled in green

Figure 50. Orientation of the PC boad is shown

Figure 51. Jumper wires connected to box lid

Figure 52. PCB soldered to the box lid
  1. Lay the PCB down onto the wires in the orientation shown in Figure 50 above. Now you're ready to solder to the PCB. Bring each wire in turn up from the bottom through the corresponding hole on the PCB and solder on the top of the board. The finished soldering job is shown in Figure 52.
  2. The final connections to make are the battery holder wires to the PCB and the lid. Before doing that, however, it's a good idea to extend the battery holder wires with the 3" red and black multi-strand wires. These are tougher than the the multi-strand wires of the battery holder itself and will hold up better to wear and tear from opening and closing the box to replace the battery. Begin by stripping the 3" wires and the battery holder wires about 3/4" as shown in Figure 53 below.
  3. Next twist the red wires together and the black wires together and solder the connections as shown in Figure 54.
  4. Cut two 1" sections of the smaller diameter (3/32") heat-shrink tubing. Then slip it over the soldered wires as shown in Figure 55. Pass a lighter flame back-and-forth under the tubing to shrink it tightly around the wires. Alternatively, you can drag the tip of the soldering iron back-and-forth over the tubing. Strip back the free ends of the wires about 1/8" to complete the battery holder extensions as shown in Figure 56.
Stripping the 3" multi-strand and battery holder wires Soldering the wires together Twisting the wires together Completed battery holder extensions
Figure 53. Stripping the 3" multi-strand and battery holder wires Figure 54. Soldering the wires together Figure 55. Slipping heat-shrink tubing over the twisted wires Figure 56. Completed battery holder extensions
Connecting the battery holder Connection of the black wire to lug 1 of the 9VDC jack Standoff wrapped in electrical tape PC board with ICs mounted
Figure 57. Connecting the battery holder Figure 58. Connection of the black wire to lug 1 of the 9VDC jack Figure 59. Standoff wrapped in electrical tape Figure 60. Final assembly with ICs mounted in sockets
  1. Now you can connect the battery holder to the PCB and the lid. The connection points are circled in green in Figure 57 above. The red wire of the battery holder connects to the hole marked B(+) on the PCB. The black wire connects to lug 1 of the 9VDC jack on the lid. A closeup of this is shown in Figure 58. The connection is circled in green.

  2. Use the remaining 4-40 bolts to bolt the PCB to the standoffs. Check the standoff in the lower right-hand corner to make sure that the wire connected to hole 5 doesn't come in contact with the standoff. If it looks like that may be the case, wrap electrical tape around the standoff as shown in Figure 59.
  3. Optocoupler showing dot at upper rightInsert the ICs into the sockets on the PCB. It's a good idea to discharge yourself by touching a grounded pipe or even the wooden leg of a table before handling the ICs. These are static-sensitive parts. Remember the notches in the socket? Well, there's a corresponding notch in the end of each IC. When you put an IC in a socket, the notches must be at the same end. Start with the LM386. This goes in the holder to the upper left on the board. Refer to Figure 60. Place the IC on the socket and pinch the pins gently if necessary to guide them into the holes. When all the pins are aligned, push down firmly on the IC to seat the pins. Repeat with the 555 timer to lower left and the 556 timer in the middle. Both of the PS2501 optocouplers go in the socket at lower right. Note the small light-colored dot in one corner of the optocoupler. You may need a magnifying glass to see the dot on the IC. Orient the dot in the socket as shown in Figure 60. A closeup of a PS2501 is shown to the right.

Set the box aside and go on to preparing the cables.

 

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