IR Multi-Board Assembly Instructions
Note: The following assembly instructions were originally written for version 1 of the IRMB. If you are assembling a version 2 board, the procedure is same except that the 1N4148 diode can simply be inserted on the top of the board rather than added to the bottom as described below.
The IRMB can be assembled for either a horizontal or a vertical installation. The soldering involved in assembling the horizontal version is easier than what's required to assemble the vertical version. If you don't feel comfortable soldering in "tight spaces" on a PC board, it's probably best to try the horizontal version first. Users with more soldering experience should have no difficulty assembling either version.
Assembling the Horizontal Version of the IRMB
Since the horizontal version is easier, let's start there. For reference throughout the assembly procedure, the following photos show the bottom and top views of an IRMB(v1) fully-assembled for horizontal use. (You can click on any photo for a larger version.)
 |
 |
 |
| Bottom View | Top View | Heat-Shrink Removed |
Parts List for Horizontal IRMB (All parts are available at www.JRHackett.net)
| Label | Description |
| D1 | Diode, 1N4148 |
| R1 | Resistor, 47 ohms, 1/4 Watt |
| R2, R3 | Resistor, 1k, 1/4 Watt |
| R4 | Resistor, 100k, 1/4 Watt |
| C1 | Capacitor, .01 uF Ceramic |
| Q1, Q2 | Transistor, KSP2222A |
| None | Header, female, 4-pin, straight (programming connector) |
| IRLED | Infrared LED |
| PNA4602 | IR Detector |
| None | 1N4148 Diode |
| None | Header, male, 5x2, straight (breadboard/cable connector) |
| IC1 | IC Socket, 8-pin, machined |
Assembling the horizontal version of the IRMB is fairly straight-forward. As usual, working from the smallest to the largest parts will facilitate keeping the parts in place while soldering. The above Parts List reflects this approach, and you can simply install the parts in order from the top to the bottom of the Parts List.
The following procedures should be observed as you populate the board:
- Thorougly clean the board before soldering. A "Scoth-Bright" plastic abrasive pad works well for this purpose.
- Be sure to orient the two transistors correctly before inserting and soldering - the rounded sides of the transistors are facing each other, as shown in the photos and on the IRMB silk-screen
- As you can see in the above photos, the leads of the IRLED are bent at a right angle before inserting and soldering the LED. Be sure to orient the LED correctly (the shorter cathode lead is inserted in the square pad on the IRMB) before you bend and solder the leads.
- The PNA4602 is inserted so that the rounded portion is facing out from the IRMB and the leads are left straight so that the 4602 stands up on the IRMB, not bent down covering its silk-screen label. Insert the 4602 and solder only its center lead to hold it in place.
- Next, attach the 1N4148 diode (on the bottom of the board, as shown in the first photo above) to the 4602 leads by shortening and bending the diode's cathode lead around pin 3 of the 4602 (toward the edge of the IRMB) and its anode lead around pin 1 (toward the center of the IRMB) and solder them both in place. (I would like to be able to say that this is a clever space-saving arrangement on my part, but the truth is that somewhere between the prototype and the production run of the IRMB the diode mysteriously disappeared, and I failed to notice it!)
- At this point you may want to rub the bottom of the board a few times on a piece of emery-type sandpaper to remove any sharp edges. You can use flux remover to clean the bottom of the board, but I have found that ordinary paint thinner and a tooth brush works just as well for this purpose, and it's easier on your hands.
- Now you are ready to insert and solder the 5x2 male header. As you can see in the above photos, this header is inserted from the bottom of the IRMB and soldered on the top of the IRMB. To do this step, you may find it helpful to insert the longer ends of the header into a breadboard, place the IRMB on top with the shorter ends of the header inserted into the pads underneath IC1. (You may need to use a small shim to make sure the IRMB sits level on the header before soldering.)
- Once the 5x2 male header is soldered in place, snip of the excess leads on the top of the IRMB and carefully inspect the connections for accidental solder bridges and other problems. (When the 8-pin machine socket is installed in the next step, this area will no longer be available for modification, so double check everything!)
- Finally, insert the 8-pin machined socket from the top of the IRMB (the square pad is for pin #1) and solder it on the bottom of the IRMB. clean the board again and insert a PICAXE-08M (properly oriented) into the 8-pin socket. If you intend to use the IRMB in an "echo" application (i.e., obstacle detection involving both the transmission of IR signals and the reception of IR echos in the same application) be sure to add heat-shrink tubing to shield the IR-LED. For a simple way to test the completed IRMB, see below.
Assembling the Vertical Version of the IRMB
The assembly of the vertical version of the IRMB is very similar to that of the horizontal version, with a couple of notable exceptions. For reference throughout the assembly procedure, the following photos show the bottom and top views of an IRMB fully-assembled for vertical use. (You can click on any photo for a larger version.)
 |
 |
| Bottom View | Top View |
 |
 |
| Heat-Shrink Removed | Looking Down from Top |
The Parts List for the vertical version is almost identical to that of the horizontal version, but I'm presenting it again because the soldering order is somewhat different due to the diffent orientations of the IRLED and the PNA4602.
Parts List for Vertical IRMB (All parts are available at www.JRHackett.net.)
| Label | Description |
| D1 | Diode, 1N4148 |
| R1 | Resistor, 47 ohms, 1/4 Watt |
| R2, R3 | Resistor, 1k, 1/4 Watt |
| R4 | Resistor, 100k, 1/4 Watt |
| C1 | Capacitor, .01 uF Ceramic |
| PNA4602 | IR Detector |
| None | 1N4148 Diode |
| Q1, Q2 | Transistor, KSP2222A |
| None | Header, female, 4-pin, straight (programming connector) |
| IRLED | Infrared LED |
| None | Header, male, 5x1, straight (cable connector) |
| None | Header, female, 5x1, right-angle (breadboard connector) |
| IC1 | IC Socket, 8-pin, machined (See text) |
As usual, working from the smallest to the largest parts will facilitate keeping the parts in place while soldering. The above Parts List reflects this approach, and you can simply install the parts in order from the top to the bottom of the Parts List.
The following procedures should be observed as you populate the board:
- The leads of the PNA4602 are bent (at a right angle) downward so that the rounded portion of its plastic body is facing up from the IRMB. Insert the 4602 and solder only its center lead to hold it in place.
- Next, attach the 1N4148 diode (on the bottom of the board, as shown in the first photo above) to the 4602 leads by shortening and bending the diode's cathode lead around pin 3 (toward the edge of the IRMB) and its anode lead around pin 1 (toward the center of the IRMB) and solder them both in place.
- Be sure to orient the two transistors correctly before inserting and soldering - the rounded sides of the transistors are facing each other, as shown on the PC board silk-screen
- As you can see in the above photos, the leads of the IRLED are not bent for the vertical version of the IRMB. Also, in this version its a good idea to raise the bottom of the IRLED about 0.1 inch off the IRMB before soldering. When the heat-shrink tubing is slid down over the IRLED, this extra step helps produce a better IR shield (which can be important in some applications). I have found the easiest way to do this is to snap a 2-pin section from a male header, use pliers to pull the two pins out of the plastic spacer and then insert the leads of the IRLED all the way into the black plastic before inserting the LED into the IRMB for soldering (click on the fourth photo for a better view). Be sure to orient the LED correctly (the shorter cathode lead is inserted in the square pad on the IRMB) before you solder the leads.
- At this point you may want to rub the bottom of the board a few times on a piece of emery-type sandpaper to remove any sharp edges. You can use flux remover to clean the bottom of the board, but I have found that ordinary paint thinner and a tooth brush works just as well for this purpose, and it's easier on your hands.
Now we get to the challanging part of the assembly of the vertical version of the IRMB! In place of the 5x2 male header used in the horizontal version, the vertical version has two different headers installed beneath IC1: a 5-pin right-angle female header which is used to connect the IRMB to a breadboard (with a 5-pin male header in between), and a 5-pin straight male header used if you want to connect the IRMB via a 10-pin ribbon cable. [If you don't think you will be using a cable connection, the male header could be omitted now and added later if you change your mind.] In either case, we need to modify the 8-pin machined socket of the horizontal version because, if we didn't, we would be in a "catch-22" situation. If we installed the right-angle female header first, it would make it impossible to solder the 8-pin socket and, conversely, if we installed the 8-pin socket first it would make it impossible to solder the female header!
The solution to this dilemma is to modify the 8-pin machined socket as follows: 1) using small diagonal pliers, cut the socket in half down its center-line, 2) snip off the protruding sections of the two cross-pieces you just cut in half, 3) (optonal) sand the cuts smooth. In effect, this converts one 8-pin DIP socket into two 4-pin SIP sockets. (Of course, if you already have 4-pin SIP sockets you can skip this procedure!)
Now we are ready to complete the vertical IRMB assembly as follows:
- First, insert (from the top) and solder (on the bottom) the lower 4-pin female SIP for IC1. Then snip and sand the excess leads on the bottom of the IRMB. This step is important because the body of the right-angle female header (next step) should be as close to the bottom of the IRMB as possible.
- Next, insert the 5-pin right-angle female header (from the bottom) in the lower row of 5 holes under IC1. Use a small clamp to hold the header tightly against the bottom of the IRMB and solder the leads on the top of the IRMB. To physically strengthen the female connector, you may also want to bend and solder a piece of bare wire around it as shown in the first photo above.
- Then, insert the 5-pin straight male header (from the bottom) in the upper row of 5 holes under IC1. To do this step, you may find it helpful to insert the longer ends of the male header into a breadboard, place the IRMB on top with the shorter ends of the header inserted into the holes underneath IC1. (You may need to use a small shim to make sure the IRMB sits level on the header before soldering.)
- Finally, insert (from the top) and solder (on the bottom) the upper 4-pin female SIP for IC1. Clean the board again and insert a PICAXE-08M (properly oriented) into the two 4-pin female SIPs. If you intend to use the IRMB in an "echo" application (i.e., obstacle detection involving both the transmission of IR signals and the reception of IR echos in the same application) be sure to add heat-shrink tubing to shield the IR-LED.
Testing the Assembled IR Multi-Board
To test either version of the completed IRMB, insert it into a breadboard with +5v and Ground connected to the appropriate pins on the breadboard connector (see the silk-screen on the IRMB) and connect an LED and current-limiting resistor between output 1 on the connector and Ground. Write a simple program to repetitively blink the LED. The following code snippet would be one way to accomplish this:
symbol LED = 1
do
toggle LED
wait 1
loop
To download the program, you will need a suitable programming adapter. If you have been following the PICAXE Primer column in Nuts & Volts, you should already have one. If not, see the UPA-4x4 programming adapter available on this site.
If you have any problems getting your IR Multi-Board to function properly, email me at Ron@JRHackett.net and I will do what I can to help.