Building a 4 Port Packet Controller

From Ohio Packet
Revision as of 22:17, 23 June 2021 by Opadmin (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

This page serves to be a guide for those wishing to build a 4 port packet controller on a Raspberry Pi 3 B+ or similar hardware. This design allows any combination of software TNC (Direwolf or G8BPQ's QtSoundModem) or G8BPQ's C port of ARDOP modem for HF. This means the controller can have any combination of up to 4 300/1200/2400/4800/9600 baud packet and/or ARDOP modems running simultaneously. When coupled with G8BPQ's excellent packet switch, this allows for a low cost controller to house a multiport packet system or to act as a "network TNC" for other software, including Outpost PPM, Winlink Express, BPQ32, XRouter and others which support the AGWPE and/or KISS over TCP protocols. It uses the very popular Linksys WRT54G or BEFSR41 router as an enclosure as well as acts as a 3 or 4 port 10/100 megabit network switch to allow expansion of controllers and/or addition of other network devices. When coupled with a WRT54G, this can also include providing a wireless access point or if flashed with DD-WRT firmware, bridging to a wireless access point (Wireless client). This should cost under $100 USD to build, most of the part values are not critical.

4PPC Schematic.jpg

Before starting this build

1) It is assumed there is a working Raspberry Pi 3 B+ with Raspian/Raspberry Pi OS 10 installed. This will probably work for Raspbian 9 and hopefully 11
2) Remote access via SSH has been setup. Once this build is complete, the Raspberry Pi 3 B+ will run headless
3) The onboard soundcard has been disabled. This is accomplished by editing /boot/config.txt and adding the line

dtparam=audio=off

Then reboot

4) While the software setup is believed to be safe, please be sure that all important data is backed up in case something goes wrong.
5) All software setup will happen after the hardware build is complete.


Required parts

1) 1x 24x12 hole perf board
2) 4x 10k 1/4w resistors
3) 4x 2n2222 Transistor or equivalent
4) 4x 1n4004 Diode or similar
5) 8x 50K Potentiometer or similar
6) 4x 10uF Electrolytic Capacitors
7) 4x USB Soundcards, no specific chipset needed
8) 2-3ft of Ribbon cable, multicolor suggested
9) 4x 18" Devicenet 2PR22 or equivalent cable
10) 1x Raspberry Pi 3B or 3B+
11) 1x 12VDC to 5VDC downconverter
12) 1x WRT54G versions v2.0 or above or BEFSR41 v4.0 or above
13) 8-12" of 22awg solid wire (Petsafe or equivalent)
14) 1/8" Heatshrink tubing
15) 1/4" Heatshrink tubing
16) 1x RJ-45 connector and 6-8" of CAT-5 type cable
17) 4x DB9 solder type female connector, cup type leads recommended
18) 4x DB9 Hoods, metal plated recommended
19) 9/64ths or 5/16ths inch drill bit and drill
20) Soldering iron with fine tip and solder
21) Electrical tape
22) Bench vice (optional)


Assembly

1) Starting with a 24x12 hole perf board, take one of the 2n2222 transistors and place it 8 holes back and with pin 1 (emitter) 4 holes in from the left

4PPC 1st 2n2222 mounted.jpg

2) Take one of the 1n4004 diodes and on the ringed side, bend the lead 180 degrees downward

4PPC 1st 1n4004 bent.jpg

3) Insert the 1n4004 diode directly behind the 2n2222 with it's anode (no stripe) directly behind the 2n2222 emitter and it's cathode (striped, bent 180 degrees) behind the 2n2222 base (center pin)

4PPC 1st 1n4004 mounted.jpg

4) Take one of the 10K resistors and bend one lead 180 degrees, similar to the 1n4004 in step 2

4PPC 1st 10k bent.jpg

5) Insert the 10k resistor where the long lead goes through the same hole as the 2n2222 base (center pin) and the resistor itself goes through the pin one hole away from the 2n2222.

4PPC 1st 10k mounted.jpg

6) Flip the perf board over, bend the 2n2222 emitter, base leads towards the back of the board and the collector lead towards the front of the board. Bend both the thicker leads of the 1n4004 diode towards the front of the board. Bend the lead of the 10K resistor that shared a hole with the 2n2222 base backwards and the other lead of the 10K resistor forward.

4PPC 1st PTT leads bent.jpg

7) Take the 10K resistor lead which was bent forward and feed it back up through the perf board to the top (component side)

4PPC 10k lead fed through.jpg

8) Take the collector lead from the 2n2222 and feed it back up through the perf board to the top similarly to the 10K resistor.

4PPC 2n2222 collector feed through.jpg

9) Take the anode side of the 1n4004 (no stripe) and feed it's lead through the same row of holes in the perf board to the top as the 2n2222 collector

4PPC 1n4004 anode feed through.jpg

10) Flipping the perf board back to the component side, bend all leads towards the front of the board.

4PPC top leads front.jpg

11) Flipping the perf board over to the lead side, apply solder to the junction of the 1n4004 anode and 2n2222 emitter as well as the junction of the 1n4004 cathode and 2n2222 base+10K resistor.

4PPC ptt1 solder.jpg

12) Using wire cutters, carefully clip the excess leads on either side of the 1n4004 cathode, 2n2222 base and 10K resistor (center most junction). Do not trim the lead coming off the 1n4004 cathode and 2n2222 emitter, we will need it for connection to ground in a future step.

4PPC ptt1 lead trim bottom.jpg

13) Flipping the perf board back over, trim the diode, resistor and 2n2222 leads to be just long enough to go over the next hole towards the front of the perf board

4PPC ptt1 lead trim top.jpg 4PPC ptt1 lead trimed top.jpg

14) Skip one hole to the right and repeat the assembly of the 2n2222, 1n4004 and 10K resistor (Steps 1-13). Be careful to not trim the lead on the underside for the 1n4004 cathode and 2n2222 emitter.

4PPC ptt2 installed top.jpg 4PPC ptt2 installed bottom.jpg

15) Repeat steps 1-14 for the remaining 2 PTT circuits, when finished it should look similar to this.

4PPC 4 ptt top.jpg 4PPC 4 ptt bottom.jpg

16) Take one of the 50K potentiometers and bend the wiper pin back towards the other two pins. The original is on the left, the bent is on the right

4PPC 1st 50k pot lead bent.jpg

17) Insert the potentiometer at the back of the perf board, one row of pins from the rear all the way to the left.

4PPC 1st 50k pot inserted.jpg

18) Flipping the board over, bend the outer most lead towards the front of the board and the wiper and inner leads towards the rear of the board.

4PPC 1st 50k pot leads bent.jpg

19) Repeat steps 16-18 for the 7 remaining potentiometers, when finished it should look similar to this.

4PPC all 50k pot leads top.jpg 4PPC all 50k pot leads bottom.jpg

20) Take a 4 conductor ribbon cable and cut it to about 4-5/8" length.

In this guide the color map is
Purple: TX Audio
Blue: PTT
Green: RX Audio
Yellow: Ground

4PPC 4conductor ribbon cut.jpg

21) Strip back about 1/4" from the purple lead and 3/16" from the green lead, twist and tin with solder.

4PPC output ribbon1 stripped tinned.jpg

22) Inserting the purple wire through the perf board, bend towards the 50K potentiometer furthest from the PTT circuits. This lead will need to overlap with the lead from the 50K potentiometer, if the wire is too short, pull it back out and strip a bit more insulation and try again. Once long enough, solder the purple lead to the 50K potentiometer.

4PPC output ribbon1 txa soldered.jpg

23) Inserting the green wire through he perf board, bend towards the wiper of the adjacent potentiometer where the purple wire was soldered. This lead does not need to be as long, just long enough to overlap with the wiper lead. Once bent and sufficient length is verified, solder the green lead to the 50K potentiometer wiper.

4PPC output ribbon1 rxa soldered.jpg

24) Pull the blue and yellow wires down to the lead side of the perf board. They will be attached in a future step.

4PPC output ribbon1 ptt ground pulled.jpg

25) Repeat steps 20-24 for the next 4 conductor ribbon cable, when finished it should look similar to this.

4PPC output ribbon2 soldered.jpg 4PPC output ribbon2 soldered top.jpg

26) Repeat steps 20-24 for the 2 remaining 4 conductor ribbon cables, when finished it should look similar to this.

4PPC output ribbon all top.jpg 4PPC output ribbon all bottom.jpg

27) Take one of the USB soundcards and carefully begin to pry apart it's shell. A box cutter or similar knife along the groove seems to work well.

4PPC USB Soundcard original.jpg 4PPC USB Soundcard pry apart.jpg 4PPC USB Soundcard covers removed.jpg

28) Flipping the USB soundcard over, using a pair of needle nose pliers and a soldering iron, carefully heat the audio connectors and gently pull them away from the soundcard. It will probably take a few times rotating between pins, but it should eventually pull off the board.

4PPC USB soundcard remove mic connector.jpg 4PPC USB soundcard mic connector removed.jpg

29) Repeat this process for the other jack on the soundcard, when complete the card should look similar to this.

4PPC USB soundcard mic speaker connectors removed.jpg

30) Apply solder to the 2 solder pads furthest from the USB connector on the microphone side and center most pin on the speaker/phone side.

4PPC USB soundcard solder pads tinned.jpg

31) Take one of the 10uF electrolytic capacitors and solder it to the outer most pad on the microphone connector. Be sure to have the side with arrow pointing away from the pad. This is to block a small DC bias which is commonly present on the microphone line on soundcards. When completed it should look similar to this.

4PPC USB soundcard cap soldered.jpg

32) Bend the axial lead of the capacitor 180 degrees back towards the soundcard. Once the lead is bent over the soundcard, cut the lead to be just short of the soundcard itself.

4PPC USB soundcard cap lead bent.jpg

33) Repeat steps 27-32 for the remaining 3 soundcards.

4PPC USB soundcards all.jpg

34) Take a 3 conductor ribbon cable and cut it to about 6-3/4" length.

4PPC audio ribbon cut.jpg

In this guide the color map is
Red: Microphone Input
Orange: Ground
Yellow: Speaker output

35) Strip about 1/4" of the Red wire, twist and tin, then insert into the outer most potentiometer next to the green lead. Once overlap with the potentiometer lead is confirmed, solder into place.

4PPC audio ribbon txa soldered.jpg

36) Strip back about 3/16" of the yellow wire, twist and tin, then insert into the wiper of the outer most potentiometer wiper next to the purple lead. Once overlap with the potentiometer wiper is confirmed, solder into place.

4PPC audio ribbon rxa soldered.jpg

The 3 conductor ribbon cable should look like this from the top of the perf board.

4PPC audio ribbon1 top.jpg

37) Repeat steps 34-36 for the second 3 conductor ribbon cable cut to about 6-1/4" length to the next set of potentiometer. The third ribbon should be cut to about 5-3/4" and fourth ribbon should be cut to about 5-1/4". When finished it should look similar to this.

4PPC audio ribbon all bottom.jpg 4PPC audio ribbon all top.jpg

38) Flipping the perf board over to the lead side, pull the blue wire from the 4 conductor ribbon cable through the gap on the 3 conductor ribbon and pull it forward towards the front of the board

4PPC blue through orange back.jpg

39) Cut about 4-1/2" of the 22awg solid insulated wire for use as a ground bus wire.

4PPC ground bus wire cut.jpg

40) Strip back about 1" of insulation off one end and lay the ground bus wire along the perf board. We want it to run along right next to the 50K potentiometers, which do not have wires soldered to them as well as the 2n2222 emitter lead tails we left from previous steps. Using a box cutter or similar, cut the insulation to length which shields the bus wire, but exposes the wire where solder connections need to be made.

4PPC ground bus 1in stripped.jpg

41) Once the insulation is cut, pull the insulation away to expose the wire to each point that needs soldered.

4PPC ground bus cut slid.jpg

42) Repeat cuts of the insulation to allow connections to all potentiometers and other ground leads.

4PPC ground bus cut all.jpg

43) Carefully apply solder to each junction where a ground connection is to be made. The first connection should look similar to this.

4PPC ground bus first solder.jpg

44) The third junction is both the potentiometer as well as the 2n2222 lead. Bend the 2n2222 lead over the bus wire before applying solder.

4PPC ground bus third prep.jpg 4PPC ground bus third soldered.jpg

45) Continue soldering the ground leads and potentiometer, the finished soldering should look similar to this.

4PPC ground bus all soldered.jpg

46) Bend the ground bus wire at a right angle, towards the front of the perf board.

4PPC ground bus right angle.jpg

47) Strip back insulation to where the ground bus wire is exposed along the same row of holes with all the other PTT circuit leads.

4PPC ground bus right angle stripped.jpg

48) Pull the exposed ground bus wire through the perf board to the component side.

4PPC ground bus right angle bottom feed.jpg 4PPC ground bus right angle top feed.jpg

49) Flipping the board over to the lead side, attach stripped insulation to the exposed bus wire and bend it towards the front of the perf board. There is one point where the exposed bus wire is close to a 1n4004 cathode, 2n2222 base and 10K resistor lead. Be sure to leave sufficient space, slightly bending the ground bus wire if needed.

4PPC ground bus end bend.jpg 4PPC ground bus gap needed.jpg

50) Strip about 3/16" of insulation off the orange and yellow wires on the first couple of potentiometers, twist and tin the leads.

4PPC orange yellow strip tin.jpg

51) Cut about 3/8" of 1/8" heat shrink tube and slide it over the yellow wire, bend the orange and yellow wires together and solder them together.

4PPC orange yellow heatshrink solder.jpg

52) Slide the 1/8" heat shrink tube over the soldered junction; apply heat with a heat gun, hair dryer or similar to shrink the tubing over the soldered junction.

4PPC orange yellow soldered with heatshrink.jpg

53) Repeat steps 50-52 for the three remaining wire pairs, when finished it should look similar to this.

4PPC orange yellow all complete.jpg

54) On the first 3 conductor ribbon cable, pull apart the 3 wires, strip about 3/16", twist and tin each wire.

4PPC audio ribbon pull strip tin.jpg

55) Solder the red wire to the electrolytic capacitor, the yellow wire to the inner solder pad which has solder added and yellow wire to the inner speaker output pad.

4PPC audio ribbon soldered to soundcard.jpg

56) Repeat steps 54-55 for the remaining three soundcards.

4PPC audio ribbon soldered to soundcard all.jpg

57) Cut about 2 1/2" of orange wire, strip back about 3/16", twist and tin one end.

4PPC ptt1 gpio wire cut.jpg

58) Insert the tinned wire into the perf board adjacent to the first 10K resistor lead.

4PPC ptt1 gpio wire inserted.jpg

59) Bend the lead towards the back of the board, overlapping with the 10K resistor lead.

4PPC ptt1 gpio wire through bent.jpg

60) Apply solder to this overlap, soldering the first orange wire to the 10K resistor lead.

4PPC ptt1 gpio wire through soldered.jpg

61) Cut about 1" of orange wire, strip back about 3/16", twist and tin one end.

4PPC ptt1 ptt wire cut.jpg

62) Insert the tinned wire into the perf board adjacent to the 2n2222 lead.

4PPC ptt1 ptt wire inserted.jpg

63) Bend the leads towards the back of the board, overlapping with then 2n2222 lead.

4PPC ptt1 through bent.jpg

64) Apply solder to this overlap, soldering the second orange wire to the 2n2222 lead.

4PPC ptt1 through soldered.jpg

65) Strip the ends of the 1" second orange and neighboring blue wire, twisting and tinning the leads.

4PPC ptt1 blue stripped tinned.jpg

66) Cut about 3/8" of the 1/8" heat shrink tubing and slide over the orange wire, solder the second orange wire to the neighboring blue wire.

4PPC ptt1 blue soldered heatshrink.jpg

67) Slide the heatshrink over the soldered junction and apply heat to shrink the heatshrink tubing over the junction.

4PPC ptt1 blue soldered with heatshrink.jpg

68) Repeat 58-67 using about 3" of red wire for the second circuit, 3-1/2" of brown wire for the third circuit and 4" of white wire for the third circuit. When finished it should look similar to this.

4PPC ptt all soldered with heatshrink.jpg

69) Cut about 2" of black wire, strip back about 3/16", twist and tin one end. Insert in the hole adjacent to the ground bus wire.

4PPC ground inserted.jpg

70) Bend the tinned black wire lead towards the back of the perf board, overlapping with the copper ground bus wire, apply solder to the junction.

4PPC ground bent soldered.jpg

71) Take one of the 18" Devicenet cable and strip back about 5/8" of the outer jacket.

4PPC devicenet1 measure.jpg 4PPC devicenet1 cut.jpg 4PPC devicenet1 jacket removed.jpg

72) Fold back the braid on the Devicenet cable.

4PPC devicenet1 jacket folded.jpg

73) Carefully pull the nylon threads from the bundle and cut away the threads.

4PPC devicenet1 nylon trim.jpg

74) Separate the red/black and blue/white pairs and bare ground wire.

4PPC devicenet1 separate pairs.jpg

75) Carefully peel away the foil surrounding the red/black pair, a small cut in the foil may be needed to begin peeling away. Repeat this for the blue/white pair as well

4PPC devicenet1 remove foil.jpg

76) Separate all wires in the Devicenet cable bundle.

4PPC devicenet1 separate wires.jpg

77) Strip back about 1/8" of insulation from the red, black and blue wires, twist and tin along with the bare ground wire. Do not strip back any insulation on the white wire.

4PPC devicenet1 stripped notwhite.jpg

78) Pull apart all wires on the first 4 conductor cable, strip back about 3/16" of each wire, twist and tin the leads. Cut about 1" of 1/4" heat strink tubing and slide it over the 4 conductor cable.

4PPC output1 strip tin heathsrink.jpg

79) Cut 4 sections 3/8” lengths of 1/8" heatshrink tubing, sliding the first section over the red wire of the devicenet cable, solder the red devicenet cable to the purple ribbon cable.

4PPC output1 devicenet1 txa solder.jpg

80) Slide 1/8" heatshrink tubing over the black wire, solder the black devicenet cable to the blue ribbon cable.

4PPC output1 devicenet1 ptt soldered.jpg

81) Slide 1/8" heatshrink tubing over the blue wire, solder the blue devicenet cable to the green ribbon cable.

4PPC output1 devicenet1 rxa soldered.jpg

82) Slide 1/8" heatshrink tubing over the bare wire, solder the bare wire from the devicenet cable to the yellow ribbon cable.

4PPC output1 devicenet1 ground soldered.jpg

83) Cut about 5/8" of 1/8" heatshrink tubing over the white wire, leaving some heatshrink past the end of the white wire and slide the other heatshrink tubing over the junction of the 4 soldered wires.

4PPC output1 devicenet1 white heatshrink.jpg

84) Apply heat to the 1/8" heatshrink tubing, to cover the soldered junctions and end of the white wire.

4PPC output1 devicent1 heatshrink applied.jpg

85) Carefully pinch the heatshrink, which runs past the tip of the white wire. This will be hot from the heat gun so be careful.

4PPC output1 devicenet1 heatshrink white pinch.jpg

86) Pull all wires together and squeeze gently, slide the 1/4" heatshrink tubing over the bundle of soldered wires.

4PPC output1 devicenet1 1 4 slid1.jpg 4PPC output1 devicenet1 1 4 slid2.jpg

87) Apply heat to the 1/4" heatshrink to insulate the bundle of soldered wires.

4PPC output1 devicenet1 1 4 heatshrink applied.jpg

88) Wrap electrical tape starting over the heatshrink, wrapping past the folded back braid of the devicenet cable.

4PPC output1 devicenet1 taped.jpg

89) Repeat steps 71-88 for the remaining three devicenet cables. When finished it should look like this.

4PPC outputall devicenetall taped.jpg

90) Take the Raspberry Pi 3 and flip it upside down, we will need to locate the solder pads on the underside to attach the needed 4x GPIO pins, 2x Ground pins and 1x +5VDC power input pin.

4PPC rpi3 bottom.jpg

91) Rotating the Raspberry Pi 3 to bring the 40 pin header forward, apply heat and solder to the five right most pins. When completed it should look similar to this.

4PPC rpi3 gpio pins tinned.jpg

92) Moving to the left side of the 40 pin header, skip the left most pin, but apply heat and solder to the next two most pins. When completed it should look similar to this.

4PPC rpi3 dc pins tinned.jpg

93) Using scrap insulation from the 22awg solid wire, slide the insulation over the outer most pins on the 40 pin GPIO header. The insulation length should be slightly shorter than the pin itself. Repeat for both rows of pins on the far left and right sides.

4PPC rpi3 gpio insulate1.jpg 4PPC rpi3 gpio insulate2.jpg


94) Apply slight pressure to insulation to side it down fully onto each pin, this should expose a small amount of the tip of the pins on all 4 corners of the 40 pin header.

4PPC rpi3 gpio insulation down.jpg

95) Taking more of the 22awg solid wire insulation, slide it over the two right most pins on the 4 pin header near the 40 pin header, if present. This should be cut to full length of the pin as our only objective is insulating these pins from the perf board.

4PPC rpi3 4pin insulate.jpg

96) Carefully take the assembled perf board and line up the front two rows of holes with the 40 pin header on the Raspberry Pi 3, be sure to bundle the 5x wires coming from the under side into the gap between the 40 pin header and 4 pin header if present. Press down on the perf board and ensure that the header pin tips are visible through the perf board.

4PPC perfboard test fit1.jpg 4PPC perfboard test fit2.jpg

97) Cut about a 5" length of 2 conductor ribbon. This will be used to pick off 12VDC from the WRT54G or BEFSR41 so choose colors which represent this. In this example we will use white wire for +VCC and black wire for ground/return.

4PPC 12vdc wire cut.jpg

98) Locate the WRT54G or BEFSR41 for service, double check the device version, for WRT54G we want to use hardware versions 2.0 or above and for BEFSR41 we want to use hardware versions 4.0 or above. This is only for physical space for the Raspberry Pi 3. Earlier versions have some obstructions in the area making mounting the Raspberry Pi difficult.

4PPC wrt54g front.jpg 4PPC wrt54g bottom.jpg

99) Carefully apply pressure to one of the front legs on the WRT54G/BEFSR41, this should eventually allow the face to pry apart from the body. In some units this plastic is brittle and may break, in this example it came apart, though some damage to the plastic is visible. If there is significant difficulty in removing the face, pull out the rubber feet and look to see if there are screws holding the face to the bottom of the enclosure. This was present in some, but not all units. Once the first side is open, pull the entire face away from the remainder of the unit, exposing the internal main board.

4PPC wrt54g face removal.jpg 4PPC wrt54g face removed.jpg

100) If using a WRT54G with removable antennas, unscrew both antennas and set them aside for now then push the top of the cover towards the back, this should move it past tabs on the base of the enclosure and allow the top to be lifted up and removed.

4PPC wrt54g top removed.jpg

101) Looking towards the back of the main board, there should be one or two screws holding the main board to the bottom of the enclosure. Unscrew this screw and set it aside for now or screw it back into the bottom of the enclosure to separate the board completely.

4PPC wrt54g case screw removal.jpg

102) Strip about 3/16" of insulation off the 2 conductor ribbon from step 97, twist and tin.

4PPC 12vdc wire stripped tinned.jpg

103) Flipping the WRT54G/BEFSR41 upside down, locate the DC power connector and solder the 12VDC wire to the inner most solder point and the ground wire to the perpendicular solder point. This should provide 12VDC along the power cable.

4PPC 12vdc wire source soldered.jpg

104) On the opposite side of the 2 conductor ribbon, strip about 3/16" of insulation, twist and tin.

320px

105) On the 12VDC to 5VDC converter, locate the input pins, in this example they are labeled In- and In+.

4PPC 12vdc 5vdc converter.jpg

106) Insert the 12V lead into the In+ hole and solder into place, insert the ground lead into the In- and solder.

4PPC 12vdc 5vdc source soldered.jpg

107) Assemble approximately 6" of Cat5 ethernet cable with an RJ-45 connector attached. It is also possible to cut apart an existing cable, ideally we want the internal wires to be solid, but stranded can probably work if twisted and tinned.

4PPC 6in cat5e cut.jpg

108) Insert the RJ-45 into the Raspberry Pi3 and set the Raspberry Pi in the front right corner of the WRT54G/BEFSR41 main board to get the distance and location where the ethernet line will need to be stripped to wrap under the main board.

4PPC rpi3 ethernet placement.jpg

109) When the length is found, carefully cut through the insulation off the CAT-5 cable. This should be right at the point where the cable reaches the edge of the board.

110) Pull the insulation off the end of the CAT-5 cable, exposing the 4 pairs of wire and if present, nylon threads.

4PPC ethernet stripped pull.jpg

111) Cut any nylon threads being careful not to accidentally cut any of the 4 pairs. Separate the orange and green pairs from the brown and blue pairs

4PPC ethernet pull cut nylon.jpg

112) Carefully cut the blue and brown pairs where the insulation has been stripped back, apply about 1" of the 1/4' heatshrink to the end of insulation and apply heat to shrink over the transition between insulation and bare wires.

4PPC ethernet blue brown cut heatshrink applied.jpg

113) Untwist the ends of the orange and green wire pairs, stripping back about 1/8" of insulation from the ends.

4PPC ethernet orange green stripped.jpg

114) On the underside of the WRT54G/BEFSR54, find the LAN ethernet jack closest to the DC power connector, it will most likely be 2 rows of pins. As shown, the pins with a visible trace represent the needed pins for 100 megabit ethernet.

4PPC wrt54g ethernet pins bottom.jpg

115) On the orange and green wire pairs, bend the exposed copper wire into an L shape and apply a small amount of solder to tin the ends.

4PPC ethernet orange green bent tinned.jpg

116) Carefully solder the 4 CAT-5 wires to the pins on the WRT54G/BEFSR41. As pictures this is Orange white, Orange, Green white, skip 2, Green.

4PPC ethernet orange green soldered.jpg

117) Run the CAT-5 cable to the edge of the WRT54G board and bend the wires at the corner, bringing the insulated section of the cable towards the front right corner where the Raspberry Pi 3 will reside.

4PPC ethernet edge over.jpg

118) Cut about a 4" length of 2 conductor ribbon. This will be used to take the 5VDC from downconverter to the Raspberry Pi 3choose colors which represent this. In this example we will use white wire for +VCC and grey wire for ground/return.

4PPC 5vdc wire cut.jpg

119) Split and strip about 3/16" off the 2 conductor ribbon from step 118, twist and tin.

4PPC 5vdc wire strip tin.jpg

120) On the 12VDC to 5VDC converter, locate the output pins, in this example they are labeled Out- and Out+. Solder the appropriate wires to the output pins.

4PPC 12vdc 5vdc output solder.jpg

121) On the other end of the 5VDC ribbon, strip and tin about 1/8" from the ends.

4PPC 5vdc load strip tin.jpg

122) With the 40 pin header in the front and Raspberry Pi 3 showing the solder side up, attach the 5VDC (white) and ground (grey) wires to the two tinned pins. Be extra careful here to ensure the correct pins are soldered. This is the DC power input to the Raspberry Pi 3. A short between pins, wiring this backwards or shorting any other pins could damage the Raspberry Pi 3, the 12v to 5v converter and/or the host WRT54G/BEFSR41 itself.

4PPC 5vdc power soldered.jpg]

123) Flipping the Raspberry Pi 3 with the component side up, reapply the perf board over the 40 pin header, ensuring the 5 floating wires from the bottom of the perf board are bundled together through the opening outside of the 40 pin header.

4PPC perfboard attach.jpg

124) Taking the first PTT line which is orange, carefully bend it, leaving a loop of slack and cut the wire to length to be soldered to the first pin.

4PPC ptt1 gpio line cut.jpg

125) Strip about 1/8" of insulation off the orange wire, twist, tin and solder to the outer most header pin.

4PPC ptt1 gpio line tin soldered.jpg

126) Repeat steps 124 and 125 for the second PTT which is red, the third PTT which is brown, the ground which is black and fourth PTT which is white.

4PPC ptt all ground tin soldered.jpg

127) Strip about 3/4" of the 22awg solid wire, feed the wire through the mounting hole on the Raspberry Pi 3 closest to the USB connectors, running through the left most column and third row from the front.

4PPC mount wire left stripped.jpg

128) Bend the bare copper wire around the perf board and back around the under side to secure the wire into place on the perf board.

4PPC mount wire left wrapped.jpg

129) Pulling the 22awg wire tight, bend the wire along the bottom of the Raspberry Pi 3, laying between the solder pins of the 40 pin header.

4PPC mount wire bent gpio.jpg

130) Bend the remainder of the 22awg wire through the opposite mounting hole on the Raspberry Pi 3, stripping off insulation which runs past the perf board, inserting the bare 22awg wire through the perf board.

4PPC mount wire right stripped.jpg

131) Bend the bare wire around the perf board to hold the board in place.

4PPC mount wire right wrapped.jpg

132) Looking down at the perf board, verify that the bare copper wires holding the perf board to the Raspberry Pi 3 are not creating any shorts.

4PPC mount wire short check.jpg

133) Flip the Raspberry Pi 3 to the solder side and apply strips of electrical tape to insulate it from shorting against the WRT54G/BEFSR41 main board. The inner two strips will need a corner cut away as to not interfere with the insertion or removal of the SD card. On the last piece of tape, be sure to pull the 5VDC power wire to run underneath the Raspberry Pi 3 and over top the 3 prior lengths of electrical tape.

4PPC rpi3 tape bottom1.jpg 4PPC rpi3 tape bottom2.jpg 4PPC rpi3 tape bottom3.jpg 4PPC rpi3 tape bottom4.jpg 4PPC rpi3 tape bottom5.jpg

134) If needed, apply electrical tape to the 12V to 5V converter. In the converter used here, there is a small blue LED which is intentionally not covered to allow visibility to the power status.

4PPC 12vdc 5vdc tape wrap1.jpg 4PPC 12vdc 5vdc tape wrap2.jpg

135) With everything taped up, reattach the antennas if the WRT54G is in use to prepare for a power up test. Insert the needed SD card into the Raspberry Pi.

4PPC wrt54g antenna attached.jpg

136) Plug in an ethernet cable to an open port on the back of the WRT54G/BEFSR41 (not the ethernet jack closed to the DC power connector) and the 12VDC supply to the 12V power connector. If all goes well, the WRT54G/BEFSR41 will power up as will the Raspberry Pi 3, two of the LAN interfaces show link and the USB sound cards will light up or flash.

4PPC wrt54g powerup test.jpg

137) If the power up test is successful, remove the 12VDC supply and flip the WRT54G/BEFSR51 to where the ethernet jacks are forward. Take a length of about 1-1/2 of electrical tape and cover the ethernet jack closest to the power connector. This port has the Raspberry Pi 3 soldered to it internally and should not be used to plug in an external device.

4PPC wrt54g ethernet cover1.jpg 4PPC wrt54g ethernet cover2.jpg

138) Take the upper cover of the WRT54G/BEFSR41 and 9/64ths or 5/16ths drill bit and drill the first hole for the Devicenet cable. Keep in mind 4 holes will need to be drilled which is a somewhat tight fit, especially on the WRT54G. It is suggested to start towards the top of the cover and near the corner of the LAN port segment.

4PPC wrt54g drill hole1.jpg

139) Drill 3 additional holes to permit the remaining 3 devicenet cables out of the WRT54G/BEFRS41. Be careful not to get too close to the antenna connector on the WRT54G, it may have a small hood which consumes space outside of the existing hole in the cover.

4PPC wrt54g drill hole all.jpg

140) Carefully push the first Devicenet cable through the hole drilled. The tolerance is fairly tight, it may be necessary to squeeze the tip of the Devicenet cable to pass through the hole.

4PPC wrt54g devicenet1 feed.jpg

141) Feed the remaining three Devicenet cables through the other holes drilled, pulling them through.

4PPC wrt54g devicenet feed all.jpg

142) Take the main board from the WRT54G/BEFSR41 and reattach it to the bottom of the enclosure, reattaching the screw(s) as needed.

143) Take the top cover to the WRT54G/BEFSR41 and slide it back into position with the bottom of the enclosure. Be sure to line up the two tabs near the rear and slide the top cover forward to pull into place.

4PPC wrt54g case top install.jpg

144) Swinging the WRT54G/BEFSR41 around, it may be needed to adjust the position of the Raspberry Pi 3 slightly. the Raspberry Pi 3 itself should be slightly behind the row of LEDs on the front of the WRT54G/BEFSR41 so the front face plate can attach without issue.

4PPC wrt54g case top on.jpg

145) Carefully take the front cover of the WRT54G/BEFSR41 and press it back into place. This is generally not an easy fit, it may take some rocking back and forth to get things to snap back into place. It's probably easiest to set one side and then work to snap the other side.

4PPC wrt54g face slide on1.jpg 4PPC wrt54g face slide on2.jpg

146) Take one of the female DB9 connectors and apply solder to pins 1.

4PPC db9 tin pin1.jpg

147) Repeat step 146 for pins 2, 3 and 5.

4PPC db9 tin pin2 3 5.jpg

148) Flip the DB9 over and repeat step 146 for pin 6.

4PPC db9 tin pin6.jpg

149) Apply solder to the outside of the DB9 connector next to pins 1 and 6. This is needed to ground the outside of the DB9.

4PPC db9 tin shell.jpg

150) Taking the first devicenet cable that comes out of the WRT54G/BEFSR41, strip back about 5/8" of it's jacket, pulling the braid back over the jacket, removing the foil surrounding the red/black pair and blue/white pair, strip, twist and tin all colored wires and the bare grounding wire.

4PPC devicenet1 db9 strip tin.jpg

151) Take the white wire and attach it to DB9 pin 2. This pin is in the middle of 2 other pins which have had solder applied.

4PPC devicenet1 white pin2 solder.jpg

152) Repeat step 151 for red to pin 1, black to pin 3, blue to pin 5.

4PPC devicenet1 red pin1 black pin2 blue pin5 solder.jpg

153) Flip the DB9 over and solder the bare wire to pin 6.

4PPC devicenet1 bare pin6 solder.jpg

154) Cut about 3/4" of a single wire, stripping back about 3/16" on one side and 3/8" on the other side. Tin the 3/16" side.

4PPC devicnet1 db9 shell wire cut prep.jpg

155) Bend the tinned 3/16" section 90 degrees and solder to the connector of the DB9 connector with the remainder of the wire running about parallel to the bare wire from the Devicenet cable.

4PPC devicenet1 db9 shell soldered.jpg

156) Wrap the opposite end of the shell jumper around the bare wire at some convenient length then apply solder to solidify the connection.

4PPC devicenet1 db9 shell bare wrapped.jpg 4PPC devicenet1 db9 shell bare soldered.jpg

157) Take one of the DB9 shells and lay the DB9 connector plus devicenet cable in it, mark about 1/4" past where the shell connector ends and wrap about 5-7 turns of electrical tape around this point. This will grow the outside diameter of the devicenet cable to where the DB9 shell teeth will "bite" into the wire, holding it firmly in place and offsetting any stress from the soldered pins.

4PPC devicenet1 db9 hood.jpg 4PPC devicenet1 db9 hood taped.jpg

158) Add the second half of the shell, inserting the connector locking screws facing the front of the connector. The electrical tape will make bringing the two sides a bit more difficult, if possible use a bench vice or similar to hold the two sides together.

4PPC devicenet1 db9 hood 2 sides.jpg

159) Run the shell screw through both halves into the mating nut, tighten screw to bring both sides together. Repeat on other side of DB9 shell. When finished it should look similar to this.

4PPC devicenet1 db9 complete.jpg

160) Repeat steps 146-159 for the remaining 3 Devicenet cables.

4PPC devicenet db9 complete all.jpg

---

Software Setup If you have an existing Raspberry Pi 3 node running Direwolf, QtSoundModem, ARDOPC, you can configure each now. The soundcard numbers may need to be found experimentally, the PTT GPIO numbers are as follows:

Port 1 uses GPIO 21
Port 2 uses GPIO 20
Port 3 uses GPIO 16
Port 4 uses GPIO 12


Controller Setup

If you are starting with a fresh system, the following scripts will help with the setup.

This script will perform several functions to build the base controller:

1) Apply all available system updates (this can take considerable time)
2) Install needed packages to build direwolf and run controller functions
3) Download and install the current version of Direwolf
4) Create symbolic links to allow direwolf to be run out of the source tree
5) Installs suite of scripts to be run by the pi user during system administration
6) Executes a script to name soundcards based upon the USB port they are plugged in (sc0, sc1, sc2, sc3)
7) Restarts systemd-udev-trigger to apply soundcard changes
8) Builds base direwolf configuration files
9) Installs startup scripts for each of the 4 direwolf instances
10) Create systemd units for 4 direwolf instances
11) Adds command aliases to aid in administering the controller

It is encouraged that the script be reviewed prior to being run. Once logged into the Raspberry Pi 3 the script can be downloaded with

wget https://ohiopacket.org/files/scripts/controller_setup.sh

Once downloaded, consider pulling it into a preferred text editor and review each step. Afterwards, make the script executable and run it.

chmod +x controller_setup.sh
sudo ./controller_setup.sh

The script will print a basic summary of each step, after each step completes, it will prompt to "Press any key" to continue. This is intended to allow capturing of error messages along the way or review of items changed. If something goes wrong, pressing CTRL+C will exit out of the script.

Once completed, the script will return to a bash prompt. At this point a reboot can be performed, the system should come back in a minute or two and the soundcards, if they have an activity LED should all begin flashing on startup indicating that all 4 instances of Direwolf are running.

---

Read only setup

This script is optional but will reconfigure the Raspberry Pi 3 B+ to run in a read only state. This should increase the lifespan of the SD card. This is appropriate for systems which function as a Node, Chat system and/or Winlink RMS Gateway. This does not permit file storage needed to run a BBS. If you do want to run a BBS, this step can be skipped or other arrangements can be made for BBS file storage.

This script will

1) Remove packages which do not permit running from a read only filesystem
2) Install busybox-syslogd and remove rsyslogd
3) Update cmdline.txt to boot read only
4) Create symbolic links for specific paths and files, allowing them to run from tmpfs
5) Moves random-seed to tmpfs and update systemd unit to suite
6) Updates /etc/fstab to mount /boot and / read only
7) Adds several tmpfs entries to /etc/fstab to allow read write to system RAM
8) Appends lines to /etc/rc.local to update /etc/resolv.conf and restore alsactl levels

This too should be reviewed prior to being run. Once logged into the Raspberry Pi 3 the script can be downloaded with

wget https://ohiopacket.org/files/scripts/readonly_setup.sh

Once downloaded, consider pulling it into a preferred text editor and review each step. Afterwards, make the script executable and run it.

chmod +x controller_setup.sh
sudo ./controller_setup.sh

The script will print a basic summary of each step, after each step completes, it will prompt to "Press any key" to continue. This is intended to allow capturing of error messages along the way or review of items changed. If something goes wrong, pressing CTRL+C will exit out of the script.

Once completed, the script will return to a bash prompt. At this point a reboot can be performed to test out the read only startup. The system should come back in a minute or two. If all goes well, a reconnection with SSH should succeed. From this point forward, whenever an edit needs to be made to a file stored on the SD card, the following command must be run:

rw

When the changes are finished, run the command

ro

In some cases, the "ro" command will report "mount: /: mount point is busy." and a remount read only is not possible. Generally this is due to a service opening a file read write, a reboot will always correct this condition.

---

BPQ installation

If you wish to run BPQ on this system, a script has been written to help get the base setup in place.

This script will

1) Create a running folder of /home/pi/bpq
2) Download the most recent version of pilinbpq from G8BPQ's website
3) Download the accompanying HTMLpages and unzip them
4) Create a startup script that allows updating of pilinbpq on restart
5) Create, enable and start a systemd unit to handle the start, stop and restart of BPQ

This too should be reviewed prior to being run. Once logged into the Raspberry Pi 3 the script can be downloaded with

wget https://ohiopacket.org/files/scripts/bpq32_setup.sh

Once downloaded, consider pulling it into a preferred text editor and review each step. Afterwards, make the script executable and run it.

chmod +x bpq32_setup.sh
sudo ./bpq32_setup.sh


With all of this completed, the controller needs some configuration to become operational. At a minimum, /home/pi/bpq/bpq32.cfg must be edited to an appropriate callsign. It is suggested to update ALIASes to reflect the system location and/or role. Each of the ports should be updated to reflect appropriate information, a frequency and baudrate is suggested. The Telnet port allows remote access to the node, pay careful attention to the USER= lines which contain usernames and passwords for access.

More configuration information can be found in the 4 Port Controller Administration Guide