Introduction: IV Swinger 2 - a $50 IV Curve Tracer

By
About: I used to get paid for designing computer and networking hardware and software. Now I design stuff for fun and give it away.

NOTICE: Please contact me at csatt1@gmail.com if you are interested in building the hardware for people who don't have the time, skills, or tools to do it themselves. I get requests occasionally from such people, but cannot do this myself.

IV Swinger 2 is an IV curve tracer for photovoltaic (PV) solar panels (modules). There is also a version that works with PV cells.

In 2017, the total cost of materials was about $50 (for the least expensive version) but may be more to build a single IV Swinger 2 since that assumes some items are purchased in larger quantities. It also does not include shipping, tax, tools or the Windows/Mac laptop that is required to use it.

This is a successor to IV Swinger, which was used for Gil Masters' CEE176B class at Stanford in 2015 and 2016. IV Swinger 2 was used for that class from 2017 until Gil's retirement in 2020. It is my sincere hope that IV Swinger 2 will be used at other colleges and universities that teach PV principles. For that matter, it can be very useful for anyone wanting to learn about the effects of insolation/irradiance, temperature, and especially shading on the power production of a single PV module. While the software does support calibration, there are no guarantees as to the device’s precision or accuracy.

The following two YouTube videos demonstrate IV Swinger 2 in action:

Part I (7:02)

Part II (6:48)

The hardware and software designs and documentation for the original IV Swinger and IV Swinger 2 are on GitHub:

https://github.com/csatt/IV_Swinger

I also want to acknowledge Jason Alderman (whom I have never met or even corresponded with). I stumbled on his wireless IV curve tracer design (http://jalderman.org/?p=57), and that was the "Aha!" moment without which IV Swinger 2 might not have happened.

The original IV Swinger 2 designs (for PV modules and PV cells) use an Adafruit "Perma-Proto" board and hand-cut, hand-stripped, hand-soldered hookup wires for all of the connections between the resistors, capacitors, ICs, and power/ground rails. Hookup wire is also used for the connections between the Perma-Proto and the Arduino.

Now there are printed circuit boards (PCBs) available that provide all of these connections, making the construction much simpler, faster, and more mistake-proof. Furthermore, there are versions of the PCBs that support on-board solid-state relays (SSRs) or field-effect transistors (FETs) instead of the off-board electromagnetic relays (EMRs).

It is still possible to build an IV Swinger 2 using a Perma-Proto; the documentation still exists and the software doesn’t care. However, it is recommended that moving forward, all IV Swinger 2 constructions use the PCB-based designs.

Still interested? First, let's get familiar with the basics of the hardware design so you know what you'll be building.

Step 1: Understand the Hardware Design / Choose Variant

Understand the hardware design:

Although it is possible to build an IV Swinger 2 without understanding how the hardware works, you will get more out of it if you do and will have a better chance of being able to diagnose any problems.

The IV Swinger 2 hardware consists of the following:

  • Load:
  • Capacitors
  • Bleed resistor
  • Relay
  • Ammeter and voltmeter:
  • Shunt resistor
  • Voltage divider
  • Op amp circuits
  • Arduino UNO

The following YouTube video gives a high-level description of how a capacitor load is used to trace an IV curve:

IV Swinger 2 Hardware Overview (6:00)

There are seven design variants.

Perma-Proto:

  • PV module version, electromechanical relay (EMR)
  • PV cell version, electromechanical relay (EMR)

PCB:

  • PV module version, electromechanical relay (EMR)
  • PV module version, solid-state relays (SSR)
  • PV module version, field-effect transistors (FET)
  • PV cell version, electromechanical relays (EMR)
  • PV cell version, solid-state relays (SSR)

The GitHub repository (https://github.com/csatt/IV_Swinger) contains Fritzing design files for the Perma-Proto module and cell IV Swinger 2 designs. Images of the Breadboard View and Schematic View (module only) are attached to this step in the Instructable. The repository also contains the PCB designs that were created with the EAGLE tool (free version). Each PCB has a PDF folder that contains the schematic of the circuit design. These schematics are for the PCB only. Even if you are building a PCB-based IV Swinger 2, it is still useful to look at the schematic created with the Fritzing tool for the original design, since it includes the external components (Arduino, relay, binding posts) and it shows the internal op amps in the TLV2462 IC. The circuit design is described in detail in the document titled “IV Swinger 2: Design and Theory of Operation” (file name IV_Swinger2_Design.pdf), available in the GitHub repository under docs/IV_Swinger2.

Choose Variant:

Deciding which variant to build comes down to three choices:

  • Perma-Proto vs PCB
  • PV module vs PV cell
  • EMR vs SSR vs FET

As mentioned earlier, it is recommended that from now on, everyone should choose PCB over Perma-Proto. This is especially true if you need to build the cell version, since there is no Instructable and no step-by-step instruction document for the Perma-Proto cell version. If you need to trace IV curves for high-power PV cells, one of the cell versions must be chosen. You should know, however, that the cell versions:

  • Are more expensive and difficult to build
  • Require an external “bias battery”
  • Are trickier to calibrate
  • Are not necessary at all for low-power cells, which can be accommodated with a “scaled-down” module version (please read the document titled “IV Swinger 2: Hardware Scaling”, filename: IV_Swinger2_Scaling.pdf to determine whether your cells will work with a scaled module version and what component values to use to accomplish that.)

From an educational standpoint, more can be learned from IV curves for PV modules since they show the effects of module-level electronics (namely bypass diodes).

Choosing between the electromechanical relay (EMR) versions, solid-state relay (SSR) versions, and field-effect transistor (FET) version comes down to:

  • Cost: the EMR versions are the least expensive to build. The FET version (module only) is next, and the SSR versions are the most expensive.
  • Availability: The EMR modules are very common and available from many sources. The SSRs are a very specific part that has been nearly impossible to find during the global semiconductor shortages of 2021 and 2022. As of April 2023, the problem remains, and it appears likely the part may no longer be in production. The FET version was developed specifically to address the unavailability of the SSR parts but also requires a part (CPC1596) that could encounter similar shortages.
  • Simplicity: the SSR and FET versions have fewer external wires to connect and no EMR to mount in the case
  • High voltage tolerance: The SSR and FET versions can handle PV modules with a Voc up to 80 volts. The EMR version will wear out quickly at voltages over about 40V and may even burn out immediately with a Voc higher than some (unknown) voltage.
  • Lifespan: An EMR has moving parts and will eventually wear out, even at lower voltages.
  • Repairability: The EMR is easy to replace if it goes bad. The SSRs and FETs are difficult to replace (but shouldn’t go bad, so this point may be moot).
  • Sound: An EMR clicks when it switches. This can be a nice audible cue that an IV curve was swung. The SSRs and FETs are silent.
  • Isc accuracy: The first measurement that the SSR and FET versions capture is at a voltage closer to zero than the EMR version, so the (extrapolated) value of Isc is more accurate.
  • Current calibration: As of software release v2.8.0, all three versions support the more accurate advanced current calibration. However, the EMR version requires manually connecting a jumper wire for the measurements.
  • Track record: the EMR and SSR versions have been built many times and are known to work well. The FET version is new (as of Feb 2022). It should be noted that there have been some cases of FETs burning out, and this is not understood (and could be a fluke.)

There are separate Instructables for each of the PCB variants:

Please switch now to the one that corresponds to your choice unless you have decided to build the original (deprecated) Perma-Proto design for PV modules.

The remainder of this Instructable is for the original Perma-Proto design for PV modules.

There is a PDF document attached to this step that has all of the steps in this Instructable. You can print that out and use it to check off the tasks as you complete them.

Attachments

Step 2: Install Software

Before spending time building the hardware, install the Arduino software and the IV Swinger 2 application on the laptop that you’ll be using.

  • Install Arduino IDE:

https://www.arduino.cc/en/Main/Software

  • Install IV Swinger 2 app:

Mac: Yosemite (10.10) or higher

Windows 7 or higher

https://github.com/csatt/IV_Swinger/releases/latest

Make sure both of the above come up before proceeding. If necessary, upgrade the OS on your computer.

Step 3: Buy Parts

The necessary parts to build an IV Swinger 2 can all be purchased online from Amazon and Digi-Key. The attached spreadsheet is a bill of materials (BOM).

The Amazon link below is a “wish list” that can be used to populate your cart. Most of the items come in quantities larger (in some cases much larger) than needed to build a single IV Swinger 2. You may of course choose to find equivalents that are offered in smaller quantities. Also, many of the items are things that you may already have, so don’t necessarily just blindly order everything on the list.

The Digi-Key link is a pre-populated shopping cart. Again, you’ll want to check if you already have any of the items before ordering. NOTE: any part that has ALT_n (e.g., ALT_1, ALT_2) in the “Customer Reference field should be ordered only if the primary version of the same part is marked as “backorder”.

In both cases, it is possible (or probable) that certain items will go out of stock or be discontinued, so you’ll have to find suitable substitutions. Occasionally I check the lists and modify them myself, but not very often. Send me a message if you are uncertain about identifying a substitute part.

Alternately, the following CSV file may be used to order from Digi-Key, Mouser or possibly other suppliers that support uploading a BOM spreadsheet. It includes the manufacturer, manufacturer’s part number, Digi-Key part number, and Mouser part number:

https://github.com/csatt/IV_Swinger/raw/master/docs/IV_Swinger2/Perma_Proto_construction/PermaProto_Digikey_Mouser.csv

Also included below is the link to donate to the original Arduino developers. I donate $5 for each $10 Arduino clone that I buy. This is your choice, but I think it is the right thing to do.

  • Amazon:

http://a.co/8RzkH2P

  • Digi-Key:

https://www.digikey.com/short/q99cnzz1

  • Donate to Arduino.cc:

https://www.arduino.cc/en/Main/Contribute

Attachments

Step 4: Gather / Buy Tools

Here is the list of tools that I used:

  • Holding:
    • Vise
    • Clamp
    • 3rd hand tool with magnifying glass
    • Tape (preferably Kapton, but Scotch ok)
    • Long/needle-nosed pliers
  • Soldering:
    • Soldering iron (preferably temp controlled solder station)
    • Tip cleaner
    • Rosin core solder
    • Solder sucker or solder wick
  • Cutting:
    • Utility knife
    • Coping saw (or hacksaw)
    • Wire cutter (flush cut)
    • Wire stripper
  • Drilling:
    • Drill
    • 1/16" bit (pilot for 9/64")
    • 1/8" bit (Perma-Proto)
    • 9/64" bit (standoffs)
    • 11/64" bit (pilot for 13/64")
    • 13/64" bit (binding posts)
    • 3/8" Forstner bit (preferred - USB cable hole)
  • Other:
    • Digital Multimeter (DMM)
    • Small Phillips screwdriver
    • 9V battery
    • Sharpie
    • Ruler
    • Water spray bottle

Step 5: Modify Perma-Proto

The 1/2-size Perma-Proto is just a bit too long to fit in the baseball display case.

  • Cut Perma-Proto to length:
    • 6.5cm (cut between row 24 and 25) _________
    • Score with knife on both sides, and then break off end
  • Drill new mounting hole in cut-off end of Perma-Proto:
    • 1/8" bit (1/16" pilot), ~5.5cm between hole centers _________

Step 6: Manually Test the Relay Module

    This will confirm that your relay module is the correct type and that it is functional.

    • With Arduino powered off:
      • Connect relay module GND to Arduino GND with female-to-male jumper ___________
      • Connect relay module VCC to Arduino 5V with female-to-male jumper ___________
      • Connect female-to-male jumper to relay module IN (male end not connected) ___________
    • Connect Arduino to laptop with USB cable:
      • Arduino: green LED should be on ___________
      • Arduino: yellow LED should be blinking once per second (assuming fresh-out-of box Arduino, running the default "Blink" sketch) ___________
      • Relay module: red LED should be on, green LED should be off ___________
      • Relay module: C (middle) terminal should have continuity with NC (bottom) terminal and no continuity with NO (top) terminal ___________
    • Connect the male end of the jumper from the relay module IN pin to the GND socket near the blinking yellow LED on the Arduino ___________
      • Relay module: should click and green LED should come on ___________
      • Relay module: C (middle) terminal should have continuity with NO (top) terminal and no continuity with NC (bottom) terminal ___________
    • Connect the male end of the jumper from the relay module IN pin to the "13" socket near the blinking yellow LED on the Arduino ___________
      • Relay module: should click once per second ___________
      • Relay module: green LED should blink exactly opposite from the Arduino's yellow LED ___________

    Step 7: Prepare for Soldering

    Soldering NOTES

    • Order is important:
    • Avoids earlier steps obstructing later steps
    • Avoids melting insulation of already-soldered wires
    • Minimizes time by batching as many solder joints as possible into a single "step"
    • If you don't have a lot of soldering experience, read this:

    Adafruit: Common Soldering Problems

    • If you need practice soldering, use the scrap end of the Perma-Proto
    • Solder bridges between holes in different numbered rows (e.g. hole 16H to hole 17H) or between the power and ground rails must be removed with a solder sucker or solder wick and/or X-acto knife.
    • Solder bridges are ok between holes in the same numbered row (e.g. holes 10B and 10C). However, if an empty hole is plugged, it may block a wire/lead/pin that comes in a later step and will have to be cleared with a solder sucker or solder wick.
    • Don't skip the incremental testing steps. Mistakes found now are easy to identify and fix but will be very difficult or impossible if you wait until the whole thing is built.

    Wire cutting NOTES

    • Print the PDF attached to this step to help cut wires to their correct lengths and to strip them properly
    • Measure #10 – it should be 38.0mm if your printer prints to scale
    • The numbered templates are named for the number of hole gaps spanned for purely vertical or horizontal wires (e.g. adjacent holes use #1)
    • The lettered templates are for a few wires that are diagonal or not routed directly between two holes
    • To use:
    • Lay the uncut wire over the template with the end aligned with the right end of the template
    • Use wire cutters to gently dent the insulation at the positions of the two ends of the insulation and the left end of the wire
    • Use wire strippers to strip the left end at the rightmost dent
    • Cut the wire to length at the leftmost dent
    • Hold the wire by the insulation with needle nosed pliers
    • Use wire strippers to strip the left end at the first dent
    • Total counts for each color and length:
    • BLACK
    • #2: 2
    • #3: 4
    • #4: 2
    • RED
    • #2: 3
    • #A: 1
    • BLUE
    • #1: 1
    • #6: 1
    • GREEN
    • #1: 1
    • #B: 2
    • WHITE
    • #C: 1

    Attachments

    Step 8: BLACK (ground) Wires

    Solder BLACK (ground) wires to Perma-Proto (16 joints):

    • Only the ones with both ends connecting to Perma-Proto holes
    • Insert all wires before soldering. Tape down on front to hold in place. Lengths (total/insulation template#) and holes:
    • 20.0/6.0mm (#3) 7J - upper ground rail (blue stripe), hole 7 _______
    • 20.0/6.0mm (#3) 12J - upper ground rail (blue stripe), hole 12 _______
    • 20.0/6.0mm (#3) 7F - 7E ______
    • 20.0/6.0mm (#3) 12F - 12E ______
    • 22.5/8.5mm (#4) 7D - 11D ______
    • 22.5/8.5mm (#4) 12D - 16D ______
    • 17.5/3.5mm (#2) 12A - lower ground rail (blue stripe), hole 12 _______
    • 17.5/3.5mm (#2) 21A - lower ground rail (blue stripe), hole 21 _______
    • Flip board upside down and hold with vise or 3rd hand tool. Solder all 16 joints _______
    • Inspect with magnifying glass to make sure all joints are good and there are no solder bridges _______
    • Trim all 16 leads _______

    Test ground plane:

    • Test continuity:
    • Upper ground rail to lower ground rail _______
    • Upper ground rail to all holes in row 7 _______
    • Upper ground rail to holes A-E in row 11 _______
    • Upper ground rail to all holes in row 12 _______
    • Upper ground rail to holes A-E in row 16 _______
    • Upper ground rail to holes A-E in row 21 _______
    • Test NON-continuity:
    • Upper ground rail to upper/lower power rail ______
    • Upper ground rail to holes:
    • 6J ______
    • 8J ______
    • 11J ______
    • 13J ______
    • 6E ______
    • 8E ______
    • 10E ______
    • 13E ______
    • 14E ______
    • 15E ______
    • 17E ______
    • 20E ______
    • 22E ______

    Step 9: RED (+5V) Wires

    Solder RED (+5V) wires to Perma-Proto (8 joints):

    • Only the ones with both ends connecting to Perma-Proto holes
    • Insert all wires before soldering. Tape down on front to hold in place. Lengths (total/insulation template#) and holes:
    • 17.5/3.5mm (#2) 8J - upper power rail (red stripe), hole 8 _______
    • 17.5/3.5mm (#2) 13J - upper power rail (red stripe), hole 13 _______
    • 17.5/3.5mm (#2) 19J - upper power rail (red stripe), hole 19 _______
    • 21.5/7.5mm (#A) 17E - 19F _______
    • Flip board upside down and hold with vise or 3rd hand tool. Solder all 8 joints _______
    • Inspect with magnifying glass to make sure all joints are good and there are no solder bridges _______
    • Trim all 8 leads _______

    Test power plane:

    • Test continuity:
    • Upper power rail to holes F-J in row 8 _______
    • Upper power rail to holes F-J in row 13 _______
    • Upper power rail to holes F-J in row 19 _______
    • Upper power rail to holes A-E in row 17 _______
    • Test NON-continuity:
    • Upper power rail to upper/lower ground rail _______
    • Upper power rail to holes:
    • 9J _______
    • 14J _______
    • 18J _______
    • 20J _______
    • 18D _______

    Step 10: BLUE (and One GREEN) Wires

    Solder BLUE (and ONE GREEN) wires to Perma-Proto (6 joints):

    • Only the BLUE ones with both ends connecting to Perma-Proto holes
    • Only the very short GREEN one
    • Insert all wires before soldering. Tape down on front to hold in place. Lengths (total/insulation template#) and holes:
      • 27.5/13.5mm (#6) 11H - 17H (BLUE) _______
      • 15.0/1.0mm (#1) 20J - 21J (BLUE insulation optional) _______
      • 15.0/1.0mm (#1) 9I - 10I (GREEN insulation optional) _______
    • Flip board upside down and hold with vise or 3rd hand tool. Solder all 6 joints. _______
    • Inspect with magnifying glass to make sure all joints are good and there are no solder bridges _______
    • Trim all 6 leads _______

    Test BLUE (and ONE GREEN) wire soldering:

    • Test continuity:
      • Hole 9F to hole 10F _______
      • Hole 11F to hole 17F _______
      • Hole 20F to hole 21F _______
    • Test NON-continuity:
      • Hole 8F to hole 9F _______
      • Hole 10F to hole 11F _______
      • Hole 11F to hole 12G _______
      • Hole 16F to hole 17F _______
      • Hole 17F to hole 18F _______
      • Hole 19G to hole 20G _______
      • Hole 21F to hole 22F _______

    Step 11: 1/4W Resistors

    Solder 1/4W resistors to Perma-Proto (16 solder joints):

    • Insert all resistors before soldering. Tape down on front to hold in place.
      • R1 (150k): 20F - 20D _______
      • R2 (7.5k): 21F - 21D _______
      • R3 (1k): 6B - 10B _______
      • R4 (1k): 17G - 21G _______
      • R5 (22k): 13A - 17A _______
      • R6 (22k): 19H - 22H _______
      • Rf (75k): 15C - 19C _______
      • Rg (1k): 16B - 19B _______
    • Flip board upside down and hold with vise or 3rd hand tool. Solder all 16 joints _______
    • Inspect with magnifying glass to make sure all joints are good and there are no solder bridges _______
    • Trim all 16 leads _______

    Use multimeter to measure exact resistances of soldered resistors:

    Measuring between the specified Perma-Proto holes listed below also verifies the soldering.

    • R1 (150k): 20I - 20A ____________
    • R2 (7.5k): 21I - 21B ____________
    • R3 (1k): 6E – 10A ____________
    • R4 (1k): 17J - 21I ____________
    • R5 (22k): 13E - 17D ____________
    • R6 (22k): 19I - 22G ____________
    • Rf (75k): 15E – 19D ____________
    • Rg (1k): 16E – 19D ____________

    The measured values of R1, R2, Rf, and Rg could be useful, so keep this record. All values should be within the tolerance of the resistors if the soldering was done correctly.

    Additional tests of resistor soldering:

    • Test NON-continuity:
      • Hole 6A to hole 7C _______
      • Hole 9A to hole 10A _______
      • Hole 10A to hole 11A _______
      • Hole 12B to hole 13B _______
      • Hole 13B to hole 14B _______
      • Hole 14E to hole 15E _______
      • Hole 15E to hole 16E _______
      • Hole 16E to hole 17D _______
      • Hole 19A to hole 20A _______
      • Hole 20B to hole 21B _______
      • Hole 16J to hole 17J _______
      • Hole 19I to hole 20I _______
      • Hole 21I to hole 22I _______

    Step 12: IC Sockets

    Solder IC sockets to Perma-Proto (16 joints):

    • Insert both sockets before soldering. Tape down on front to hold in place.
    • Make sure notch is on the left end
    • TLV2462 (left) socket:
      • Pin 1: hole 8E ________
      • Pin 5: hole 11F _______
    • MCP3202 (right) socket:
      • Pin 1: hole 13E ________
      • Pin 5: hole 16F ________
    • Flip board upside down and hold with vise or 3rd hand tool and solder all 16 joints ________
    • Inspect with magnifying glass to make sure all joints are good ________

    Test socket soldering:

    • Test continuity:
      • TLV2462 (left) socket hole 1 (lower left) to Perma-Proto hole 8C ______
      • TLV2462 (left) socket hole 2 to Perma-Proto hole 9C ______
      • TLV2462 (left) socket hole 3 to Perma-Proto hole 10C ______
      • TLV2462 (left) socket hole 4 to Perma-Proto ground rails ______
      • TLV2462 (left) socket hole 5 (upper right) to Perma-Proto hole 11J ______
      • TLV2462 (left) socket hole 6 to socket hole 7 ______
      • TLV2462 (left) socket hole 7 to Perma-Proto hole 9G ______
      • TLV2462 (left) socket hole 8 to Perma-Proto upper power rail ______
      • MCP3202 (right) socket hole 1 (lower left) to Perma-Proto hole 13B ______
      • MCP3202 (right) socket hole 2 to Perma-Proto hole 14B ______
      • MCP3202 (right) socket hole 3 to Perma-Proto hole 15B ______
      • MCP3202 (right) socket hole 4 to Perma-Proto ground rails ______
      • MCP3202 (right) socket hole 5 (upper right) to Perma-Proto hole 16G ______
      • MCP3202 (right) socket hole 6 to Perma-Proto hole 15J ______
      • MCP3202 (right) socket hole 7 to Perma-Proto hole 14J ______
      • MCP3202 (right) socket hole 8 to Perma-Proto upper power rail ______
    • Test NON-continuity:
      • TLV2462 socket hole 1 to Perma-Proto ground rails ______
      • TLV2462 socket hole 1 to socket hole 2 ______
      • TLV2462 socket hole 2 to socket hole 3 ______
      • TLV2462 socket hole 3 to socket hole 4 ______
      • TLV2462 socket hole 5 to Perma-Proto ground rails ______
      • TLV2462 socket hole 5 to socket hole 6 ______
      • TLV2462 socket hole 7 to socket hole 8 ______
      • TLV2462 socket hole 8 to Perma-Proto ground rails ______
      • MCP3202 socket hole 1 to Perma-Proto ground rails ______
      • MCP3202 socket hole 1 to socket hole 2 ______
      • MCP3202 socket hole 2 to socket hole 3 ______
      • MCP3202 socket hole 3 to socket hole 4 ______
      • MCP3202 socket hole 4 to Perma-Proto hole 17D ______
      • MCP3202 socket hole 5 to Perma-Proto hole 17J ______
      • MCP3202 socket hole 5 to socket hole 6 ______
      • MCP3202 socket hole 6 to socket hole 7 ______
      • MCP3202 socket hole 7 to socket hole 8 ______
      • MCP3202 socket hole 8 to Perma-Proto ground rails ______

    Step 13: Filter Capacitors

    Solder 0.1uF capacitors to Perma-Proto (4 joints):

    • Insert both capacitors before soldering. Bend leads on back to hold in place.
      • C3: 7G - 8G ________
      • C6: 12G - 13G ________
    • Flip board upside down and hold with vise or 3rd hand tool and solder both joints ________
    • Inspect with magnifying glass to make sure joints are good and there are no solder bridges ________
    • Trim all 4 leads _______

    Solder 2.2nF capacitors to Perma-Proto (4 joints):

    • Insert both capacitors before soldering. Bend leads on back to hold in place.
      • C4: 10C - 11C ________
      • C5: 11I – 12I ________
    • Flip board upside down and hold with vise or 3rd hand tool and solder both joints ________
    • Inspect with magnifying glass to make sure joints are good and there are no solder bridges ________
    • Trim all 4 leads _______

    Test capacitor soldering:

    • Test continuity:
      • C3 left leg (7G) to Perma-Proto ground rails _______
      • C3 right leg (8G) to Perma-Proto upper power rail _______
      • C6 left leg (12G) to Perma-Proto ground rail _______
      • C6 right leg (13G) to Perma-Proto upper power rails _______
      • C4 left leg (10C) to Perma-Proto TLV2462 socket hole 3 _______
      • C4 right leg (11C) to Perma-Proto ground rails _______
      • C5 left leg (11I) to Perma-Proto TLV2462 socket hole 5 _______
      • C5 right leg (12I) to Perma-Proto ground rails _______
    • Test NON-continuity:
      • C3 left leg (7G) to Perma-Proto hole 6G _______
      • C3 left leg (7G) to C3 right leg (8G) _______
      • C3 right leg (8G) to Perma-Proto hole 9G _______
      • C6 left leg (12G) to Perma-Proto hole 11G _______
      • C6 left leg (12G) to C6 right leg (13G) _______
      • C6 right leg (13G) to Perma-Proto hole 14G _______
      • C4 left leg (10C) to Perma-Proto hole 9C _______
      • C4 left leg (10C) to C4 right leg (11C) _______
      • C5 left leg (11I) to Perma-Proto hole 10I _______
      • C5 left leg (11I) to C5 right leg (12I) _______
      • C5 right leg (12I) to Perma-Proto hole 13I _______

    Step 14: Two More GREEN Wires, One WHITE Wire

    Solder one more GREEN wire to Perma-Proto (2 joints):

    • Insert wire and tape down on front to hold in place. Length (total/insulation template#) and holes:
      • 40.5/26.5mm (#B) 9G - 14C _______
    • Bend and route between the IC sockets in a Z (on top of black wires)
    • Flip board upside down and hold with vise or 3rd hand tool and solder both joints ____ ____
    • Inspect with magnifying glass to make sure joints are good and there are no solder bridges ________
    • Trim both leads ________

    Solder one more GREEN wire to Perma-Proto (2 joints):

    • Insert wire and tape down on front to hold in place. Length (total/insulation template#) and holes:
      • 40.5/26.5mm (#B) 9C - 19D ______
    • Route around capacitor C4 and over the top of the previous green wire
    • Flip board upside down and hold with vise or 3rd hand tool and solder both joints ________
    • Inspect with magnifying glass to make sure joints are good and there are no solder bridges ________
    • Trim both leads _______

    Solder one WHITE wire to Perma-Proto (2 joints):

    • Insert wire and tape down on front to hold in place. Length(total/insulation template#) and holes:
      • 36.0/22.0mm (#C) 8A - 15B _______
    • This wire should NOT lie flat, but should be a small "arch" to leave clearance for the blue wire to connect to hole 13B
    • Flip board upside down and hold with vise or 3rd hand tool and solder both joints ________
    • Inspect with magnifying glass to make sure joints are good and there are no solder bridges ________
    • Trim both leads _______

    Test GREEN and WHITE wire soldering:

    • Test continuity:
      • TLV2462 socket hole 1 to MCP3202 socket hole 3 ________
      • TLV2462 socket hole 2 to Perma-Proto hole 19A ________
      • TLV2462 socket hole 7 to MCP3202 socket hole 2 ________
    • Test NON-continuity:
      • TLV2462 socket hole 1 to Perma-Proto ground rails ________
      • TLV2462 socket hole 1 to socket hole 2 ________
      • TLV2462 socket hole 2 to socket hole 3 ________
      • TLV2462 socket hole 7 to socket hole 8 ________
      • MCP3202 socket hole 1 to socket hole 2 ________
      • MCP3202 socket hole 2 to socket hole 3 ________
      • Perma-Proto hole 18A to hole 19A ________
      • Perma-Proto hole 19A to hole 20A ________

    Step 15: Insert Bleed Resistor

    Insert 47ohm bleed resistor Rb:

    • Tape down on front to hold in place, but don't solder yet
      • 6H - 6C _______

    Step 16: Insert Load Capacitors

    Insert 1000uF load capacitors:

    • Tape down on front to hold in place, but don't solder yet
      • 1J - 4J (shorter lead / stripe side (-) on the right (4J), IMPORTANT!) ________
      • 1A - 4A (shorter lead / stripe side (-) on the right (4A), IMPORTANT!) ________

    Step 17: Solder Bleed Resistor

    Solder 47ohm bleed resistor Rb leads (2 joints):

    • DO NOT TRIM LEADS
    • Note that the resistor may have to be raised slightly to fit
    • Leads are thick so they take a longer time to heat up enough to melt solder
    • Solder to holes 6H and 6C with leads straight through holes (i.e. not bent) ________

    Step 18: Shunt Resistor

    Solder .005 ohm shunt resistor to *BACK* of Perma-Proto (2 joints):

    • Bend leads at right angle so resistor is CENTERED between bends and the lead ends are 27.5mm apart ________
    • Insert shunt resistor leads into the following holes FROM THE BACK of the Perma-Proto:
      • 4E - lower ground rail (blue stripe), hole 13 ________
    • Tape down on back to hold in place ______
    • Flip board face-up and hold with vise or 3rd hand tool and solder both joints (long heavy leads will take time to heat) ________
    • Inspect with magnifying glass to make sure joints are good and there are no solder bridges ________
    • Trim both leads _______

    Step 19: Prepare Load Circuit Zip Cord

    • NOTE: This can be any stranded AWG 18 or AWG 16 insulated wire such as from a typical household extension/lamp cord or heavier speaker wire. AWG 18 solid core is fine too (no need to "tin").
    • "A": PV- binding post to lower ground rail and shunt
      • Cut to length: 9 cm ________
      • Strip 1 cm on each end and twist strands ________
      • Crimp cable ring connector on one end using pliers (or vise / ViseGrips / crimping tool) ________
      • Heat crimp with the soldering iron and flow solder into strands ________
      • Heat the strands of the other twisted end and flow solder into the strands (i.e. "tin" it) ________
    • "B": PV+ binding post to relay module NO terminal
      • Cut to length: 9 cm ________
      • Strip 1 cm on each end and twist strands ________
      • Crimp cable ring connector on one end using pliers (or vise / ViseGrips / crimping tool) ________
      • Heat crimp with the soldering iron and flow solder into strands ________
      • Heat the strands of the other twisted end and flow solder into the strands (i.e. "tin" it) ________
    • "C": Load capacitors (+) side to relay module C terminal
      • Cut to length: 11 cm ________
      • Strip 1 cm on each end and twist strands ________
      • Heat the strands of both ends and flow solder into the strands (i.e. "tin" them) ________

    Step 20: Load Capacitor (+) Leads

    Solder (+) load capacitor leads to each other and to zip cord "C" (1 large joint):

    • DON'T COVER UP MOUNTING HOLE!
    • Leave enough room for standoff, but don't put standoff in hole when soldering; it will suck heat and wires won't get hot enough to flow solder
    • Bend lead from hole 1A so it lies flat and in the correct direction and contacts lead from hole 1J. See photo. ________
    • Solder leads to their holes (1J and 1A) ________
    • Solder capacitor leads to each other ________
    • Tack on zip cord "C" so it extends toward the top of the board, parallel to the end. Heat up tinned end of wire and capacitor leads enough to completely reflow the solder (add more solder if needed). See photo. ________
    • Make sure there is no solder bridging to any of the row 4 holes (rows 1, 2, and 3 are ok) ________

    Step 21: Load Capacitors (-) Leads

    Solder (-) load capacitor leads to each other, shunt resistor, and lead of 47ohm bleed resistor Rb that comes through hole 6C (1 large joint):

    • Use needle-nosed pliers to wrap Rb lead around shunt resistor lead between its body and hole (may also need to cut off some of Rb lead) ________
    • Bend capacitor (-) leads to contact shunt resistor lead at E4. See photo. ________
    • Solder leads to their holes (4J and 4A) ________
    • Solder capacitor (-) leads to each other and to shunt resistor lead at E4, and also make sure solder flows to Rb lead that is wrapped around shunt resistor lead ________
    • Trim other Rb lead ________

    Step 22: Zip Cord "A"

    Solder zip cord “A” to shunt/ground:

    • Tack zip cord “A” onto the end of the shunt resistor that is connected to the lower ground rail. Orient it so it extends toward the top of the board. Heat up tinned end of wire and shunt lead enough to completely reflow the solder (add more solder if needed). See photo. ________

    Step 23: Test Previous 8 Steps

    Test bleed resistor, shunt resistor, and load capacitor soldering:

    • Measure capacitance between Perma-Proto holes 1F and 4F. It should be between 1600uF and 2400uF (most likely on the smaller end) ________
    • Use multimeter to measure resistance between Perma-Proto holes:
      • Rb (47ohms): 6J - 6A _________
      • Shunt: 6A - ground rails _________
        NOTE: Shunt is only .005 ohms, which is below the resolution of the multimeter. Measured value should be approximately the same as shorting the probes together.
    • Test NON-continuity:
      • Capacitor (-) leads to capacitor (+) leads on back ________
      • Hole 6J to ground rails ________ (47Ω)

    Step 24: Insert ICs

    • Static electricity can destroy ICs. Take off your shoes and touch something metal connected to ground before handling them, if possible.
    • Insert TLV2462 in left socket _________
      • Make sure dot is on the left end (pin 1)
      • Legs may have to be bent inward slightly
    • Insert MCP3202 in right socket __________
      • Make sure notch and dot are on the left end (pin 1)
      • Legs may have to be bent inward slightly

    Step 25: Off-Perma-Proto Hookup Wires

    Solder off-Perma-Proto hookup wires to Perma-Proto:

    • Cut all wires to length, with 7mm insulation stripped from each end:
      • BLUE, 8.5cm ________
      • BLUE, 8.5cm ________
      • YELLOW, 7.0cm ________
      • YELLOW, 15.0cm ________
      • GREEN, 7.0cm ________
      • GREEN, 13.0cm ________
      • WHITE, 7.0cm ________
      • RED, 11.0cm ________
      • BLACK, 7.0cm ________
    • Use 3rd hand tool to hold wire in hole and perpendicular to the board while soldering
    • Solder BLUE wires (2 joints):
      • Perma-Proto hole 13B (8.5cm) ________
      • Perma-Proto hole 22I (8.5cm) ________
    • Solder YELLOW wires (2 joints):
      • Perma-Proto hole 14G (7.0cm) ________
      • Perma-Proto hole 20C (15.0cm) ________
    • Solder GREEN wires (2 joints):
      • Perma-Proto hole 6I (13.0cm) ________
      • Perma-Proto hole 15G (7.0cm) ________
    • Solder WHITE wire (1 joint):
      • Perma-Proto hole 16G ________
    • Solder RED wire (1 joint):
      • Perma-Proto upper power rail (red stripe), hole 15 ________
    • Solder BLACK wire (1 joint):
      • Perma-Proto lower ground rail (blue stripe), hole 15 ________
    • Inspect with magnifying glass to make sure joints are good and there are no solder bridges ________
    • Trim all 9 leads ________

    Test off-Perma-Proto hookup wire soldering:

    • Test continuity:
      • Lower BLUE wire (stripped end) to MCP3202 pin 1 ________
      • Upper BLUE wire (stripped end) to Perma-Proto hole 22F ________
      • Lower YELLOW wire (stripped end) to Perma-Proto hole 20A ________
      • Upper YELLOW wire (stripped end) to MCP3202 pin 7 ________
      • Left GREEN wire (stripped end) to Perma-Proto hole 6J ________
      • Right GREEN wire (stripped end) to MCP3202 pin 6 ________
      • WHITE wire (stripped end) to MCP3202 pin 5 ________
      • RED wire (stripped end) to Perma-Proto hole 19I ________
      • BLACK wire (stripped end) to Perma-Proto hole 7I ________
    • Test NON-continuity:
      • Lower BLUE wire (stripped end) to Perma-Proto hole 7I ________
      • Lower BLUE wire (stripped end) to Perma-Proto hole 9J ________
      • Upper BLUE wire (stripped end) to Perma-Proto hole 21I ________
      • Lower YELLOW wire (stripped end) to Perma-Proto hole 19A ________
      • Lower YELLOW wire (stripped end) to Perma-Proto hole 21B ________
      • Upper YELLOW wire (stripped end) to Perma-Proto hole 13I ________
      • Upper YELLOW wire (stripped end) to Perma-Proto hole 15I ________
      • Left GREEN wire (stripped end) to Perma-Proto hole 7I ________
      • Right GREEN wire (stripped end) to Perma-Proto hole 14I ________
      • Right GREEN wire (stripped end) to Perma-Proto hole 16I ________
      • WHITE wire (stripped end) to Perma-Proto hole 15I ________
      • WHITE wire (stripped end) to Perma-Proto hole 17I ________
      • RED wire (stripped end) to Perma-Proto hole 7I ________
      • BLACK wire (stripped end) to Perma-Proto hole 19I ________

    Step 26: Solder Male-Female Relay Jumpers to Perma-Proto

    Solder Male-Female relay module power/control jumper wires to Perma-Proto:

    • This assumes the relay module has jumper pins on the power and control inputs (some have screw terminals, like the load side)
    • Solder BLUE jumper (cut pin off) (1 joint):
      • This one needs to have its pin cut off and that end stripped. This is because the pin and its plastic housing are too tall to fit next to the Arduino in the case.
      • Solder stripped end to Perma-Proto hole 22J ________
    • Solder RED jumper pin (1 joint):
      • Perma-Proto upper power rail (red stripe), hole 10 ________
    • Inspect with magnifying glass to make sure joints are good and there are no solder bridges ________
    • Trim lead of BLUE jumper (don’t trim pin from RED jumper) ________

    Test soldering of Male-Female relay module power/control jumper wires to Perma-Proto:

    • Test continuity:
      • Need to insert a wire into female end for these
      • BLUE jumper to Perma-Proto hole 22F ________
      • RED jumper to Perma-Proto hole 19I ________
    • Test NON-continuity:
      • BLUE jumper to Perma-Proto hole 21I ________
      • RED jumper to Perma-Proto hole 7I ________

    Step 27: Solder Bypass Diodes in Series (NO LONGER NEEDED)

    NOTE: The original design called for two 15A, 45V bypass diodes (15SQ045), but this was a design error. A single 15A, 100V diode must be used.

    Step 28: Make Binding Post Connections

    Make binding post connections:

    • Remove outer nuts and washers from threaded post ________
    • Insert negative (black side) threaded post through the cable ring connector on zip cord “A” (other end is attached to shunt resistor and ground rail on bottom of Perma-Proto) ________
    • Insert positive (red side) threaded post through the cable ring connector on zip cord “B” ________
    • Bend 100V diode leads into loops that will fit onto the threaded posts (NOTE: photos show two 45V diodes) ________
    • Slide looped ends of the diode leads onto the threaded posts with the STRIPED END OF THE DIODE TOWARD THE RED SIDE ________
    • Put washers back on, over the diode lead loops ________
    • Put nuts on and tighten (not too tight – they’ll be coming off again later) ________

    Step 29: Make Relay Switching Side Connections

    Make relay module switching side (screw-down) connections:

    • Twist end of zip cord “B” (from red side of binding posts) to end of yellow wire that comes from Perma-Proto hole 20C, and solder them together ________
    • Loosen screw and insert the twisted/soldered end into the top (“Normally Open” - NO) screw terminal hole on the relay module and tighten down the screw. Tug the wires gently to make sure they are securely connected. _________
    • Loosen screw and insert the end of zip cord “C” (other end is attached to capacitor + leads on back of Perma-Proto) into the center (“Common” - C) screw terminal hole on the relay module and tighten down the screw. _________
    • Loosen screw and insert the end of the green wire that comes from Perma-Proto hole 6I into the bottom (“Normally Closed – NC) screw terminal hole on the relay module and tighten down the screw. __________

    Step 30: Make Relay Power/control Side Connections

    Make relay module control/power side (jumper) connections:

    • Connect the BLUE jumper (from Perma-Proto hole 22J) to the IN pin on the relay module __________
    • Connect the RED jumper (from Perma-Proto upper power rail hole 10) to the VCC pin on the relay module __________
    • Connect the BLACK jumper from the GND pin on the relay module to the GND pin on the Arduino (“Power” side) __________

    Step 31: Make Other Arduino Connections

    Make other Arduino connections:

    • Connect the BLUE wire from Perma-Proto hole 22I to Arduino pin 2 __________
    • Connect the BLUE wire from Perma-Proto hole 13B to Arduino pin 10 __________
    • Connect the WHITE wire from Perma-Proto hole 16G to Arduino pin 11 __________
    • Connect the GREEN wire from Perma-Proto hole 15G to Arduino pin 12 __________
    • Connect the YELLOW wire from Perma-Proto hole 14G to Arduino pin 13 __________
    • Connect the RED wire from Perma-Proto upper power rail (red stripe), hole 15 to Arduino +5V pin __________
    • Connect the BLACK wire from Perma-Proto lower ground rail (blue stripe), hole 15 to Arduino GND (near pin 13) __________

    Step 32: Test System Connections

    Test system connections:

    • Test continuity:
      • RED binding post to Perma-Proto hole 20A ________
      • BLACK binding post to Arduino GND pin (on back) ________
      • Relay module “NC” terminal (on back) to Perma-Proto hole 6J (or resistor Rb lead) ________
      • Relay module IN pin (on back) to Arduino pin 2 (on back) ________
      • Relay module GND pin (on back) to Perma-Proto upper ground rail ________
      • Relay module VCC pin (on back) to Perma-Proto upper power rail ________
      • MCP3202 pin 1 to Arduino pin 10 (on back) ________
      • MCP3202 pin 5 to Arduino pin 11 (on back) ________
      • MCP3202 pin 6 to Arduino pin 12 (on back) ________
      • MCP3202 pin 7 to Arduino pin 13 (on back) ________
      • Perma-Proto upper ground rail to Arduino GND pin (on back) ________
      • Perma-Proto upper power rail to Arduino 5V pin (on back) ________
    • Test NON-continuity:
      NOTE: temporarily disconnect the RED wire from the Arduino 5V pin for these tests (OR expect ~1.5kΩ resistance between VCC and GND in last test).
      • RED binding post to BLACK binding post ________
      • Relay module IN pin (on back) to relay module GND pin (on back) ________
      • Relay module IN pin (on back) to relay module VCC pin (on back) ________
      • Relay module GND pin (on back) to relay module VCC pin (on back) ________
    • Measure resistance:
      • BLACK binding post to Perma-Proto hole 1F ________ (should be 47 ohms)

    Step 33: System Bench Test

    System bench test:

    • Connect Arduino to laptop via USB
    • Check for smoke ☺ _______
    • Check that relay module red LED is on and green LED is off ________
    • Check that Arduino yellow LED is blinking once per second (assuming that it’s still loaded with “Blink” sketch) _______
    • Load IV Swinger 2 Arduino sketch
    • Open Arduino application on your computer ________
    • Find where the Arduino software looks for sketches:
    • Arduino->Preferences->Sketchbook location
    • Use your browser to go to:
    • https://raw.githubusercontent.com/csatt/IV_Swinger/master/Arduino/IV_Swinger2/IV_Swinger2.ino
    • Right-click and use “Save As” to save IV_Swinger.ino to the Arduino sketchbook folder found above (make sure your browser doesn’t add an extension like .txt to the file name)
    • Go back to the Arduino application and find the IV_swinger2.ino sketch using:
    • File->Open
    • The Arduino application will inform you that IV_Swinger2.ino must be in a folder named IV_Swinger2 and it will offer to do that for you. Accept its kind offer.
    • Click on arrow button or select “Upload” from “Sketch” menu _________
    • Check Arduino LEDs: Yellow “TX” LED should be blinking. This is not the same yellow LED that the Blink sketch controls. _________
    • “Nothing connected” test:
    • Open the IV Swinger 2 application ________
    • Verify that “Swing!” button text changes to RED and message below it changes from “Not connected” to “Connected” (briefly, then disappears). The “TX” LED should no longer be on. _________
    • If not, pull down the “USB Port” menu and select the correct port.
    • Click the “Swing!” button. You should see an error dialog saying “ERROR: Voc is zero volts” _________
    • 9V battery test:
    • Strip both ends of two wires and screw one end of each into the side holes of the binding posts. If you happen to have a 9V battery snap-on connector, use that. _________
    • Connect the wire from the RED binding post to the positive (smaller/male) terminal of a 9V battery (you can either tape it or hold it with your thumb) _________
    • Connect the wire from the BLACK binding post to the negative (larger/female) terminal of the same 9V battery (tape it or hold it with the same thumb as the other) _________
    • Click the “Swing!” button. You should get an IV curve that looks like the photo.

    Step 34: Prepare for Case and Final Assembly

    The acrylic baseball display case used for the IV Swinger 2 enclosure needs to have several holes drilled through it for attachments, and the “fins” on the bottom need to be trimmed off in order for everything to fit.

    Case side definitions:

    • Front: side with the USB connector
    • Back: side opposite from front
    • Left: side with binding posts and Perma-Proto
    • Right: side with relay module
    • Bottom: side with Arduino
    • Top: side closest to capacitors

    The case comes in two U-shaped halves:

    • Base: Left / Bottom (with fins) / Right
    • Lid: Front / Top / Back

    All the attachments are made to the base half. The lid half has nothing attached to it but does need a 3/8” hole in the front for the USB cable.

    Care must be taken when drilling acrylic or else it will crack:

    • Use a drill press if you have one
    • Use vise (with rubber guards) to hold case
    • Position so that the hole being drilled is close to the vise jaw
    • Start with 1/16” pilot for all holes
    • Drill slowly with light pressure
    • Spray water on hole as it is being drilled to cool
    • Use a Forstner bit to drill the 3/8” hole for the USB cable. Otherwise, you’ll have to start with 1/16” pilot and drill incrementally larger holes until you get to 3/8”

    Step 35: Cut Off Fins

    Cut fins:

    There are three fins on the bottom of the case (to cradle the baseball). Their tips need to be cut off so the Arduino clears them when it is on its standoffs. (Using longer standoffs is another possibility.)

    A coping saw or hacksaw can be used for this, among other possibilities. Just be careful not to crack or scratch the case.

    Cut off as much as possible, but at least enough so standoffs are longer than the remaining height. _________

    Step 36: Mark Holes for Arduino Standoffs

    IMPORTANT: For this step and the next three, look straight down when making the Sharpie dots (the plastic distorts/refracts if you look at an angle, and you’ll miss the mark).

    ___________________________________________________________________

    Mark holes for Arduino standoffs:

    • Attach 4 standoffs to Arduino:
    • Disconnect all wires from Arduino _______
    • Insert threaded/male end of each standoff through its hole in the Arduino from the back ________
    • Screw nuts onto the threaded ends of the standoffs on the front of the Arduino – hold the nut with your finger and turn the standoff to tighten it. Use pliers to tighten more.

    NOTE: The hole nearest the Arduino reset button doesn’t have room for a nut

    ________

    • Place the Arduino in position, standing on its standoffs (including the one without a nut). The Arduino should be touching the right side of the case, with the USB connector facing the front. The single fin should be facing toward you so the fins look like a “Y”. See photo. ________
    • PUT LID ON THE CASE. This is important because the fit is very tight! ________
    • Turn the case over and look at it from the bottom. The Arduino will probably stay in place, but you can make sure by squeezing the front and back together with the hand you’re holding it with. Use a Sharpie to mark the centers of the four holes. ________
    • Remove the lid from the case and remove the Arduino ________

    Step 37: Mark Holes for Perma-Proto Standoffs

    Mark holes for Perma-Proto:

    • Attach 2 standoffs to Perma-Proto:
      • Insert threaded/male end of each standoff through its hole in the Perma-Proto from the back. Don’t worry if the one on the capacitor end touches the soldered capacitor leads. ________
      • Screw nuts on the threaded ends of the standoffs on the front of the Perma-Proto and tighten them ________
    • Place the Perma-Proto in position. Leave 2-3mm on the side near the front. Align so the capacitors are 2-3mm below the top (if they are angled up at all, make sure the ends will be low enough not to contact the lid). _________
    • Use Sharpie to mark the centers of the two holes _________

    Step 38: Mark Holes for Relay Module Standoffs

    Mark holes for relay module:

    • Attach 4 standoffs to relay module:
    • Disconnect any remaining wires from relay module ________
    • Insert threaded/male end of each standoff through its hole in the relay module from the back ________
    • Screw nut on the threaded end on the front of the relay module and tighten it ________
    • Use the Sharpie to make a dot on the right side of the case at the following position:
    • 1.0 cm from the left (i.e. front) edge
    • 1.5 cm from the top edge

    ________

    • Hold the relay in position inside the case, with the hole of the upper left standoff aligned with the Sharpie dot. You can hold it with one hand and mark with the other – or use a small clamp to hold it in place. _________
    • Use Sharpie to mark the centers of the other three holes _________

    Step 39: Mark Holes for Binding Posts

    Mark holes for binding posts:

    • Remove top nuts, washers, diodes, cable rings, and bottom nuts from the binding posts. Remove the black plastic backing plate. ________
    • Hold the plastic backing plate in position on the inside of the left side of the case. It should be about 1mm from the rear inner edge of the case and about 1mm from the bottom. ________
    • Use Sharpie to mark the centers of the two holes ________

    Step 40: Drill 12 Marked Holes

    Drill 12 marked holes:

    • Use something pointy to make an indentation in the middle of each of the 12 Sharpie marks. The tip of the Forstner bit is perfect for this, but you can also use a needle or the tip of an X-acto blade (poke and twirl). This will keep the drill bit centered when you start drilling the hole. ________
    • Drill twelve 1/16” pilot holes ________
    • Switch to 9/64” bit and re-drill all 12 holes _______

    Enlarge 2 holes for binding posts:

    • Switch to 11/64” bit and re-drill both of the binding post holes ________
    • Switch to 13/64” bit and re-drill both of the binding post holes one more time ________

    (This step is missing in the video)

    Clean up case:

    • Remove burrs around holes with X-acto knife or your fingernails ________
    • Wash case off and dry ________

    Step 41: Install Binding Posts

    Install binding posts:

    • Insert the binding posts through their holes with the RED terminal toward the TOP of the case ________
    • Slide backing plate over the posts on the inside of the case ________
    • Thread nuts on the posts and tighten down

    Step 42: Install Perma-Proto

    Install Perma-Proto in case:

    • Insert the Perma-Proto into the case and screw down its two standoffs with two M3 screws ________

    Step 43: Make Binding Post Connections

    Make connections to binding posts:

    • Slide cable ring connector on zip cord “A” (from Perma-Proto) onto negative (BLACK side) threaded post ________
    • Slide cable ring connector on zip cord “B” (other end soldered to yellow wire from Perma-Proto) onto positive (RED side) threaded post ________
    • Put washers back on, over the cable ring connectors ________
    • Slide looped ends of the diode leads onto the threaded posts with the STRIPED END OF THE DIODE TOWARD THE RED SIDE ________
    • Put nuts on and tighten down securely

    Step 44: Install Arduino

    Install Arduino in case:

    • Attach the one Arduino standoff that won’t have a nut onto the bottom of the case with an M3 screw ________
    • Insert the Arduino, put the lid on the case, and screw down the other three standoffs with M3 screws. TIP: start all screws before tightening any of them. ________
    • Remove the lid ________

    Step 45: Connect Perma-Proto to Arduino

    Connect the 7 wires from the Perma-Proto to the Arduino:

    You may need to use needle nosed pliers for this unless you have small hands

    • Connect the BLUE wire from Perma-Proto hole 22I to Arduino pin 2 __________
    • Connect the BLUE wire from Perma-Proto hole 13B to Arduino pin 10 __________
    • Connect the WHITE wire from Perma-Proto hole 16G to Arduino pin 11 __________
    • Connect the GREEN wire from Perma-Proto hole 15G to Arduino pin 12 __________
    • Connect the YELLOW wire from Perma-Proto hole 14G to Arduino pin 13 __________
    • Connect the BLACK wire from Perma-Proto ground rail, hole 15 to Arduino GND ________
    • Connect the RED wire from Perma-Proto power rail, hole 15 to Arduino +5V pin ________

    Step 46: Connect Screw-down Side of Relay Module

    Connect wires to screw-down side of relay module:

    This needs to be done BEFORE the relay module is attached to the case, while you still have screwdriver access.

    • Insert the twisted/soldered end of zip cord “B” (from RED binding post) and yellow wire (from Perma-Proto) into the top (“Normally Open” - NO) screw terminal hole on the relay module and tighten down the screw. Tug the wires gently to make sure they are securely connected. _________
    • Insert the end of zip cord “C” (from back of Perma-Proto) into the center (“Common” - C) screw terminal hole on the relay module and tighten down the screw. Tug gently to test. _________
    • Insert the end of the green wire that comes from Perma-Proto hole 6I into the bottom (“Normally Closed – NC) screw terminal hole on the relay module and tighten down the screw. Tug gently to test. __________

    Step 47: Install Relay Module

    Install relay module in case:

    • Insert the relay module into the case and screw down its standoffs with four M3 screws. TIP: start all screws before tightening any of them. ________

    Step 48: Connect Relay Module Jumpers

    Connect wires to jumper side of relay module:

    • Connect the BLUE jumper (from Perma-Proto hole 22J) to the IN pin on the relay module _________
    • Connect the BLACK jumper from the GND pin on the relay module to the GND pin on the Arduino _________
    • Connect the RED jumper (from Perma-Proto upper power rail hole 10) to the VCC pin on the relay module _________

    Step 49: Drill USB Connector Hole

    Drill USB connector hole:

    • Put the lid on the case _________
    • Make indentation in the exact center of the USB connector using the tip of the Forstner bit (or whatever pointy thing you used for the other drill-starting indentations). NOTE: it is very important that this hole is precisely centered. You need to look at it from all four directions before making the indentation since the refraction through the plastic distorts the apparent position (you’ll see what I mean as soon as you turn it 90 degrees). _________
    • Use 3/8” Forstner bit to drill the hole
    • Drill slowly, spraying with water often
    • Reduce pressure when hole is getting close to “punching through”
    • Alternative to Forstner bit is to use following succession of normal bits:
    • 1/16”, 1/8”, 3/16”, 1/4”, 5/16”, 3/8” (untested – may need even smaller (1/32”) steps)

    ________

    • Clean up the edge of the hole with X-acto knife or your fingernail __________
    • Wash lid off and dry _________
    • Put lid on and insert the USB cable to make sure it fits __________
    • If it doesn’t, try loosening the Arduino standoff screws. This might give you enough “play” to get the connector in. Then, with the connector still in, re-tighten the screws
    • If that isn’t enough, you may have to enlarge the hole with a round file or some other way

    Step 50: Make PV Cables

    To connect to a standard PV module, you need cables with MC4 connectors.

    It is not necessary to use the same heavy gauge cable that is used in a rooftop solar installation (and on the modules themselves), assuming you only need them to be a few feet long. The nice thing about the binding posts is that you can easily swap cables with longer or shorter ones depending on the situation. The main reason for longer cables would be so the laptop and IV Swinger 2 can be in a shady spot away from the panel. These instructions intentionally do not specify the length or type of the PV cables because it is so dependent on the usage.

    If you decide that shorter cables are OK, you can just use the same zip cord that you used for the internal load connections. The only tricky part is that crimping the MC4 connectors onto smaller wire gauge doesn't really work - you need to solder them on. You also should use solder to tin the bare ends that insert into the binding posts so they are more durable.

    The downside to the binding posts is that it is possible to connect the wrong cable to the wrong post. The bypass diodes between the binding posts protect against this, but it's still a good idea to make it as foolproof as possible. Put some red tape around the one that connects to the red binding post and some black tape around the one that connects to the black binding post.

    The cable with the female MC4 connector connects to the RED binding post.

    The cable with the male MC4 connector connects to the BLACK binding post.

    Step 51: Final Test

    Your IV Swinger 2 is now complete!

    Repeat the tests you did in Step 33 (System bench test) to make sure everything got hooked back up correctly.

    You may now test it with a real PV module.

    If some amount of accuracy is important to you, see the IV Swinger 2 User Guide for instructions on how to perform a calibration. There is also a Help dialog available from the Calibrate menu in the application.

    Microcontroller Contest 2017

    Participated in the
    Microcontroller Contest 2017