Introduction: Beach Buddy: 3-in-1 Solar Phone Charger, Boombox, and Sunburn Timer Calculator

About: starwisher is a shoe hater. A music breather. A cat lover. An ink bleeder. A (mostly) canon shipper. A yarn stasher. A super stanner. A story weaver. A married twentysomething.

Imagine the ideal beach trip. The sun is shining, the skies are blue, the water is warm, and the humidity is low. You and your friends have everything you need to soak up the sun, sand and surf: a cooler filled with drinks and snacks, sunblock, flip flops, the coolest new swimwear, and the newest beach tech: the beach blanket/towel with corner pockets to fill with sand so it won't blow away; the sun shade with privacy screens and sand-fillable anchors for ultimate beach sheltering, even the spiked drink holders that keep your frosty beverages upright and sand-free.

But what's a summer day without a summer soundtrack? Good thing you've got your tunes on...your...very expensive...and very vulnerable to the Well, you do have that waterproof phone case with speakers, but it's bulky, ugly, and doesn't have a hole through which you could connect the little solar charging panel you bought (for when that fickle phone battery goes dead). Huh.

Well, while you're musing on what to do, don't forget the pain-relieving aloe gel in your cooler, for those inevitable sunburns. You're not keeping track of the time since you applied your sunscreen, admit it. You're just gonna burn. Might as well have the aspirin and Lidocaine easily accessible anyway. Enter the Beach Buddy. It's an all-in-one, water- and sand-resistant, solar charger, audio speaker system, and sunburn timer calculator.

This Instructable harnesses the power of Arduino, a UV sensor, and simple mathematics to make one nifty gadget sure to boost your outdoor summer fun - and minimize your indoor summer recovery!


For my Digital Multimedia class' final project, we were instructed to develop "a proposal for a new product, new iteration, a “masterful and well-crafted kluge”, etc. of technology and interface" in the categories of apparel/fashion, toys, tools, furnishings, and/or art.

My mind instantly flew to something having to do with sun protection, because of the horrible sunburn I suffered on the first day of class - even though I'd applied sunscreen before going to the beach that day.

What had happened? Had my sunscreen expired? Not at all - it wasn't as evenly applied as I'd thought, for one thing, but also I was in direct sun for far longer than my SPF was meant to be.

The World Health Organization has well-documented explanations for the UV Index, and the Skin Cancer Foundation goes into detail about both sunscreen sun protection factors (SPF) and the Fitzpatrick scale, a Harvard-developed system for classifying skin tones.

BUT WHAT DOES IT ALL MEAN?! And who has time for the WHO, the UV, the SCF, and the FPS?!

It all boils down to a simple formula. Once you know your Fitzpatrick scale type, you can calculate how long you can stay in the Sun without sunscreen before sunburn. Then divide that number by the current UV Index rating. Then multiply that quotient by your SPF rating - and your product is your allowed time in the sun before SPF reapplication is necessary.

So, in equation form: (Skin type time to burn ÷ UV Index) x SPF rating = time before reapplication of sunscreen.

The Beach Buddy does all this math for you with a few button pushes. Simply tell it your Skin Type and the SPF, and it'll read the UV index and spit out your timer calculation!

SO NOW, without further ado, let's get started on the Beach Buddy!

Step 1: Gather Materials

Note: the list below is rather exhaustive, and includes every last tool and supply I needed to make this project. Also note, my preferred supplier is Adafruit Industries, as it is a female-run company in a male-dominated field. Feel free to search for similar or equivalent products from alternate suppliers!

Materials - Project-Specific

  • 4x 10k ohm resistors
  • 10mm insulated standoffs (2 packs)
  • 2.1 mm DC Barrel plug > Alligator Clips
  • 9V Battery > 5.5mm/2.1mm plug
  • Acrylic sheet (thin)
  • Analog UV Light Sensor
  • 4x Breadboard-friendly momentary pushbuttons
  • Cable: 3.5mm Stereo Plug > Pigtail
  • 3x Cable: JST-PH Battery Extension
  • Enclosure
  • F/M jumper wires (1 pack)
  • LCD screen, 16x2 characters
  • 2x Lithium ion polymer battery – 3.7v 2500mAh
  • M2 screws, nuts, and washers (1 pack each)
  • M3 screws, nuts, and washers (1 pack each)
  • Mini adhesive-backed cable clips (1 pack)
  • MintyBoost Charger Kit
  • Nylon spacer (M2) (2 packs)
  • 4x Panel-mount momentary push buttons
  • PCB with connecting pads
  • Solar Charger Kit
  • Solar panel
  • 3x SPST Rocker Switch
  • Stereo Audio Amplifier
  • Stereo enclosed speaker set
  • Velcro strip
  • Wrapping wire (30AWG)
  • Optional: rub-on letters

Materials - Standard

  • 22AWG Wire, 3 colors each of stranded and solid
  • Breadboard
  • Cable Ties
  • Desoldering braid
  • Heat shrink tubing
  • Low-tack (painter's) tape
  • M/M jumper wires
  • Solder


  • Acrylic cutter
  • Arduino w/ USB cable
  • Calipers
  • Center punch
  • Cork-backed ruler
  • Dremel with cut-off-wheel attachment
  • Drill
  • Flush cutters
  • Glue gun with glue sticks
  • Heat gun
  • Needlenose pliers
  • Precision needle file set
  • Precision screwdriver set
  • File set
  • Soldering iron
  • Step drill bits
  • Tabletop vice
  • Third-helping-hand
  • Wire stripper

Download the attached .zip archive for the above list in 1) product-linked spreadsheet, 2) product-linked webpage, and 3) unlinked printable PDF form.

Step 2: Assembly - Charger

If you're using parts from Adafruit, you're in luck! Both the "solar charger" and "boom box" portion of this Instructable are derived from Adafruit tutorials. (If you've chosen other suppliers, the process should be similar.)

Assembling the Charger

  1. First, read through the Solar Charging Handbag tutorial HERE.
    • This is HUGELY IMPORTANT TO DO. While the solar charger procedures require very little modification, the MintyBoost charger should not be fully assembled. Notes below!
    • You'll be following this tutorial up until the "Mint Tin Enclosure" stage.
  2. Now, follow the steps HERE to assemble the solar charger.
    • Bend the huge capacitor over before soldering it to the board, so it'll lay flat inside the enclosure (as described here, and depicted in the first image above).
    • I followed Method 2 (stripping and soldering the wires together) to attach the solar panel to the charging cable. I cut the alligator clips off the DC-to-alligator-clip cable, and installed the DC barrel jack to the solar panel.
    • I chose not to install a thermistor or charge LEDs as mentioned in the PDF below; however, doing so would not negatively affect the Beach Buddy. Simply plan a spot for LEDs to be mounted on the project enclosure.
  3. Next, follow the steps HERE to mostly assemble the MintyBoost charger.
    • Solder on the JST battery cable that came with the solar charger instead of the battery holder (as mentioned here, and depicted in the second image above).
    • Lay down the tall capacitors and boost converter before soldering, too, as mentioned in the link/shown in the image above.
    • Ignore the instructions for incorporating the mint tin/housing the MintyBoost charger, since we'll be placing our device inside a larger enclosure.
    • Do, however, hang on to the double-sided tape included with the kit! We'll need it to attach the MintyBoost circuit board to the project enclosure.
  4. From Adafruit: "Plug the MintyBoost into the LOAD port on the solar charger, and plug a lithium polymer battery into the BATT port. Test [with a multimeter] that your MintyBoost is putting out 5 volts, then unplug the MintyBoost and solder on the USB jack as instructed.
  5. All your cables and circuits should be detachable at this point. You should have something very similar to the third image above on your work surface, only with a USB jack attached to the Mintyboost board.
  6. Test your work! Plug your cell phone charger cord into the USB jack, the battery, Mintyboost, and solar panel into their proper ports on the solar charger, and take the assembly outside. You should see your phone's battery icon change to indicate it is in the process of charging.
  7. YAY you've completed approximately 1/6th of the Beach Buddy!

Images (abc) borrowed from the Adafruit Learning System under a Attribution-Sharealike Creative Commons License.

Download the attached .zip archive for the Adafruit tutorials in PDF form.

Step 3: Assembly - Boombox

Assembling the Boombox

  1. Read through the Boombox Beach Bag tutorial HERE (included in the previous step's download).
    • Notice this tutorial accounts for a 3D Printed amp enclosure. Ignore that.
    • I chose the same MAX98306 amp for simplicity's sake.
  2. DO NOT FOLLOW PIC 2. It is an example of poor technique. Start off by pushing the (TIGHTLY TWISTED AND TINNED) black wire from inside the pigtail AND a small section of wrapping wire, longer than necessary, through the UN-TINNED L- hole.
    • TEST TO MAKE SURE THEY BOTH FIT BEFORE YOU TIN THE HOLE!!!! (I learned this the mega hard way and had to order a second amp and pigtail cable. Oops.)
    • Now carefully strip your wrapping wire and thread it through the R- hole, keeping the jump small, and solder.
    • Do this first before anything else. You will thank me.
  3. When you get to the step for assembling a slide-switch adapter, STOP. This is where we make our first modification make the device fit our needs.
  4. Cut the JST extension cable as shown in the tutorial. But instead of soldering a simple SPST slide switch into the wire, we're going to solder in one of our SPST panel mount rocker switches.
  5. Pretty simple really:
    1. Mount your rocker switch in your vise (pic 3)
    2. Tin your positive extension cable wires (pic 4)
    3. Slide two pieces of heat shrink on each wire (large and small, pic 5)
    4. Thread one wire through the hole in one of the SPST plugs (pic 6) and solder (pic 7)
    5. Repeat on the other side (pic 8).
    6. Arrange your heat shrink as shown (pic 9)
    7. And shrink with the heat gun (pic 10)
    8. Slide heat shrink onto one side of the black/negative wire, twist the two sides together (pic 11), solder and shrink the tubing.
    9. Completed rocker switch (pic 12).
      • Note: this is the only rocker switch out of the three on the BB that can be assembled separate from the device. Don't try and do it again on the other two to save time, you will regret it.

  6. Pick the tutorial back up after you've finished your rocker switch.
  7. Test it out! Once you've got something that looks like pics 13 & 14, connect the speakers to the amp, and the amp headphone plug to your cell phone, test out some tunes!
    1. Note: pic 15 shows where the gain selection should be placed once the double header is soldered on. Fitting that plastic piece over the pins adjusts the amp's volume.

Images borrowed from the Adafruit Learning System under a Attribution-Sharealike Creative Commons License.

Step 4: ABCs of Arduino, Breadboarding, and Code.


  1. Solder the strip of male header included with the LCD to the LCD ports, as described here.
  2. Solder three wires to the Adafruit UV sensor: two stranded wires to the positive and negative ports, and one solid third-color wire to the center 'out' port.
    • For the time being, splice a small length of solid wire or piece of pin header to the positive and negative ports, to allow the sensor to talk to the breadboard/Arduino in the interim.
  3. Follow the Fritzing diagram for connecting all the parts to the breadboard.
    • The breadboard compatible momentary pushbuttons will be replaced in the final render; these buttons are only for testing the code and/or parts.
    • The blue potentiometer displayed is the one that came with the LCD kit.
    • The Analog sensor diagram is not to scale/properly colored; it is, however, accurate as to pins.
  4. The LCD and pushbuttons have special instructions:
    • use female/male jumper wires to connect the LCD to the Arduino. If you are using the F/M jumper wire ribbon from Adafruit, I recommend you color-code the cables as follows:
      • Grey for Ground
      • Red for 5V
      • Blue for the Potentiometer wiper
      • Alternating yellow-and-orange for pins 2-7
    • I suggest this because it matches mostly universal wire colors to pins, and it color-coordinates to the potentiometer for ease of identification.
    • use male/male jumper wires in the color you chose for your third stranded/solid wire spools to connect the pushbuttons to the Arduino.


  1. Download the MenuBackend library by Alexander Brevig, and install to the Arduino IDE.
  2. Copy and paste the code found here on PasteBin into the Arduino IDE.
  3. Verify that the code compiles, then upload it to your Arduino.

This should be simple enough. If you've followed the Fritzing diagram, and properly installed the MenuBackend library, the code should compile without error, and the menu and buttons should be fully functional.

Here is a great resource for installing libraries to Arduino, if you haven't done so before.

Download the attached file for the Fritzing diagram in PDF form.

Step 5: How Are You Doing?

Now, in front of you, you should have:

  • 1 functional solar phone charger
  • 1 functional audio player
  • 1 functional breadboarded LCD screen and analog sensor controlled by 4 push buttons.

If you have these three things, congratulations, you are officially 50% of the way done!

Now it's time to move to the Enclosure, and drilling the holes for all the panel-mounted components.

Step 6: Enclosure Layout

Beginning the Enclosure

First, download, print out, and cut down the attached PDF files (shown in pics 1 and 2). These are templates designed to help you place components on the outside of the enclosure.

Note: The images above are designed to fit my MCM Electronics enclosure; I have also included the original .ai files should you want to change the enclosure and still use my measurements for the parts.

You will be drilling in the bottom half of the enclosure for the most part, and on three of the four walls.


  • Left Side:
    • one large round hole for the rocker switch
    • one irregular speaker hole
    • four small round holes for the speaker mounting screws.
  • Right Side:
    • one large round hole for the rocker switch
    • one irregular speaker hole
    • four small round holes for the speaker mounting screws.
  • Front Side:
    • one large round hole for the rocker switch
    • one square LCD hole
    • four large round holes for the pushbuttons.
  • Top Half of Enclosure, Large Flat Surface:
    • four small round holes for mounting the solar panel
    • one larger round hole, hidden within the area the solar panel will cover, for the panel's charging cord
    • one small square hole for the UV sensor window
    • one small round hole for the sensor mounting screw

Preparing to Drill:

  1. Tape up your enclosure with the painters' tape, to help distribute the tension generated by drilling and cutting the ABS enclosure with power tools. Then, tape the trimmed template to the outside of the box.
    • Note: There is no hole template for the main compartment; that is, where the phone is inserted into the body of the Beach Buddy for operation. That hole will depend on the size of your phone and phone case.
  2. Round Holes: using the center punch, mark the center of holes to be drilled.
  3. Irregular Holes: punch an outline around the perimeter of the hole (see pics 3 and 4)
  4. Square Holes:
    1. Draw an outline around the perimeter of the hole with a Sharpie.
    2. Using the ruler, find the horizontal center of your square hole, and draw a line across the entire width.
    3. Punch at all four corners.
    4. Punch center holes at regular intervals along the center line (about 1/4" - 3/4" wide apart, depending on the size of your components and enclosure). These will be drilled to remove the majority of the interior plastic.

Download the attached file for the layout diagrams in Adobe Illustrator and PDF form.

Step 7: Enclosure Drilling

Drilling the Holes


  1. Round Holes:
    1. using a step drill bit, SLOWLY AND WITH LIGHT-TO-MODERATE PRESSURE ON THE DRILL, drill the holes to the proper sizes (pic 1).
    2. Use first a large round file, then a precision round file to clean up and smooth the edges.
  2. Irregular Holes:
    1. Using a step drill bit, drill out the majority of the hole, working out from the center.
    2. You should now have a weirdly shaped hole in the center of your punched outline, not quite reaching any of the edges.
    3. Remove excess tape around the holes.
    4. Using a Dremel/rotary tool and a cut-off wheel, clean up the edges of the hole, perfecting the shape.
    5. Use first a large flat file, then a large round file to clean up, smooth, and round off the edges (pic 2).
    6. Use precision files to detail the edges.
  3. Square Holes:
    1. Using a step drill bit, drill along the center line, using the holes you punched as starting points (pic 3).
    2. Remove excess tape along the holes (pic 4).
    3. Using a Dremel or rotary tool with a cut-off wheel attachment, trim out the excess material and up to the outer edges of the hole, making a roughly square shape (pic 5).
    4. Use first a large flat file to smooth the edges down to an even, oblong shape (pic 6).
    5. Use precision flat and round files to finish off the holes and perfect the shape.
  4. Phone Storage Hole:
    1. Repeat the steps for a square hole as above, but in the top half of the enclosure along the left side.
    2. Refer to Pics 3, 4, 5, and 6 for guidance - my starter holes were drilled with a 3/4" step drill bit.

Step 8: Planning Out the Interior

Once you've brushed off all that plastic drilling dust, it's time to start planning the interior mounting process.

Start by screwing the insulated standoffs to the bottom of your Arduino and PCB (or, in my case, to the bottom of the Arduino mounting bumper I 3D-printed, thingiverse file HERE). Then start laying everything out inside the base.

  1. Make sure all your exterior mounted components are loosely in place. You want to make sure everything fits and screws in place easily before adding boards around it. (I did not do this, and my bottom-most pushbutton had to be glued into the enclosure, rather than screwed on. I did not leave enough room for my nut to be tightened.)
  2. Start with your largest components (your Arduino, your PCB, your 3V batteries, and your 9V battery clip) first, then fit the smaller boards in around it.
  3. Use the spaces beneath the standoffs for cable routing and battery space, since both are insulated.
  4. Think about the length of your cords. It's much easier to wrap a too-long wire once more, than to strain a too-short wire. Splice in lengths of wire if you need to.
  5. Once you've got an arrangement you like, take a photo with your cell phone for remembrance's sake.
  6. Now remove the standoffs from the Arduino and PCB, and using them as templates, punch starter holes using the center punch.
  7. Repeat with all the other boards.
  8. For the 9V battery clip, mark two small holes in the bottom of the plastic.

Step 9: Securing the Standoffs

Now drill the holes you marked. Make sure to use a piece of scrap wood beneath your drilling, to keep your surface intact and keep the plastic from warping.

  1. For your Arduino, your PCB, and your battery clip, use a 1/8" drill bit to cut a hole for your screws. These all fit M3 size screws.
  2. For your Adafruit boards, use a 3/32" drill bit. These mounting holes are sized M2.

Installing the Components

  1. Install the boards, using both the insulated and nylon standoffs, and appropriately sized screws and washers. Start from underneath and screw up into the enclosure, then use nuts to keep the boards in place.
    • Do not worry about screwing the PCB down at this time.
    • Underneath where the PCB will be, and around delicate or small solder connections, add a few mini cable clips as shown. This will help keep all these wires nice and tidy!
  2. For the Mintyboost charger board, use the double-sided foam tape we saved earlier to attach the board to the enclosure. Make sure you leave enough room to plug in and pull out a USB phone charger cord!!
  3. For the 9V clip, punch through the holes you just drilled in the plastic clip, to mark where the holes will be drilled in the enclosure body.
    • Note: the battery clip is the only component screwed on from the inside out - two small screws start from inside the clip and stick out through the bottom of the enclosure, secured with two nuts.
  4. For the li-poly batteries, use a hot glue gun to attach Velcro tape to the bodies of the batteries.
    • DO NOT APPLY GLUE TO THE BATTERY/ENCLOSURE DIRECTLY. Apply the glue to the tape, allow it to cool for just a second, and then press the tape in place.
    • I recommend applying the loop (fuzzy) side of the tape to the battery, and the hook (bristly) side of the Velcro to the enclosure.

Step 10: Panel-Mounting Power

Now comes the fun part: panel-mounting. Once these components are in place, you cannot remove them, as they will be connected to the circuit board, your devices, your batteries, etc.

View the image with notes above for placement.


  1. Push the speakers in, wires-first, from the outside.
    1. Make sure the speakers face the front of the box (i.e., the speaker is shallower on one side and deeper on the other - place the deeper portion closer to the LCD).
  2. Plug them into the female jumper wires on the audio amplifier board.


  1. Insert the LCD screen into the hole in the front panel and screw into place, header facing into the enclosure.

Rocker Switches

  1. Thread the wires attached to the rocker switch prepared in Step 3 (the audio power cable) through the left-mounted rocker switch hole, and screw the rocker switch in place.
  2. Prepare the other two rocker switches as described in Step 3, Sub-Step 5, but rather than attaching JST wires, attach two medium lengths of red wire, stripped at the ends.
    • This is done to make adding the rocker switches into battery lines easier.
  3. Thread the wires through the holes for the rocker switches, then screw the rocker switches in place with their included nuts.
  4. You should have three neatly mounted switches on the outside, and one switch sporting JST connectors/two exposed wires sticking off the back of each other switch on the inside.

Battery Clip > Rocker Switch

  1. Using a lever or your needlenose pliers, pull the little plastic piece protecting the wire connections out of the battery clip and discard.
  2. You should now be seeing short little wires attached to the battery terminals and a slide switch.
  3. CAREFULLY remove the slide switch from its place inside the clip, pulling gently on the short wires so as not to break their soldered connection.
  4. Remove the slide switch with your flush cutters and discard.
  5. Leaving a good amount of tail, clip the DC barrel jack off the 9V battery and set aside.
    • Make sure you take note of which wire is negative, and which is positive.
  6. Carefully strip a little more wire casing from the battery wires, and guide them through the hole where the slide switch used to be.
  7. Join one of the red wires attached to the front-mounted rocker switch to the positive battery clip wire. (Don't forget to put your heat shrink on first before splicing any wires!!)
    • Note: the slide switch was originally attached to the negative pole of the battery clip; I flipped this in my project and instead joined the positive pole of the battery to the rocker switch.
  8. Attach the bare red wire coming from the rocker switch, to the positive wire on the barrel jack (add wire if needed to allow easy connection with the Arduino power terminal).
  9. Attach black wire to the negative wire on the barrel jack, adding wire if necessary, and then splice it with the negative wire coming from the battery clip.
  10. Screw the battery clip down into place.

Charger Battery > Rocker Switch

  1. Very, very carefully (the soldered connections on top of the battery are very delicate), and leaving a good amount of tail, clip the JST battery connector off the end of the wires.
  2. Repeat the steps for attaching the right-mounted rocker switch, as described in steps 7 & 8 above, instead connecting the JST positive cable > mounted rocker switch > positive battery wire, and the JST negative cable > negative battery wire.
    • Don't forget to test the path of the wires to the Solar Charger BATT port; tension is not a good thing with wires this delicate - especially with these li-poly batteries. This is why we glued our Velcro on first.


  1. Route all the wires through the previously placed cable clips for neatness.

If all has gone well, you should now have three small circuit boards and one Arduino mounted to the enclosure, and two batteries, one battery clip, and three rocker switches all connected to power sources, installed in your enclosure.

Step 11: Buttoning Up the Buttons

  1. Prepare the four buttons as described for the rocker switch in Step 3, Sub-Step 5, attaching two medium lengths of your third wire color (not black or red), stripped at the ends. I chose green for my third color.
    • Note: try to keep your soldered connections and wires as straight/in line as possible; this will make wiring up the PCB to the buttons much easier.
  2. Be very careful to properly heat-shrink these button connections, to avoid short-circuits.
  3. Thread the wires through the front holes for the buttons switches, then screw the buttons in place with their included nuts and washers (pic 1).

Step 12: Perfecting the PCB

'Kay so now we have a box with all the trimmings on the outside, and the majority of the meat on the inside.

Now it's time to solder the PCB. I used a universal component PC board from RadioShack in a pinch; if I'd had more forethought, I'd have ordered this breadboard-styled perma-protoboard from Adafruit. But the additional "schematic" I designed is for the RadioShack board.

The universal schematic outlines the connections; the colorful layout includes solder points and component layout on the board.

  1. Solder the jumper connections using solid-core wire or jumper wires; I used pre-bent solid jumper wires I had on hand for my PCB.
  2. Snip and strip the male ends off the Ground and 5V female/male jumper wires, and solder those into the PCB. Leave the female ends intact to connect to the LCD.
  3. For each push button wire, solder in two unattached wires, to be soldered to our exposed button wires momentarily.
  4. I also cut a small strip of white heat shrink into four small pieces and wrote the name of each button on the tubing. I didn't shrink it, just slid it over the wires so I can identify them quickly in the future if need be.

Step 13: Completing the Circuit

  1. Now that our PCB is all soldered up, go ahead and screw it into the standoffs mounted earlier.
  2. Connect your ground and 5V wires to your LCD screen; then connect your LCD screen to your Arduino as shown in the schematic.
  3. Connect the solid wires for your button readouts to your Arduino as shown in the schematic.
  4. Making sure to add heat shrink before soldering, connect the loose wires from the PCB to their corresponding panel-mounted buttons, as described with the rocker switches in Step 10.
    • Be extremely careful and thorough in this step! You do not want to incorrectly wire a button!!
  5. Once your PCB is secured, your buttons are soldered and shrunk and wired to the Arduino, and your LCD is wired up, as well, you should have something like the picture above. Pretty, huh?

At this point, the vast majority of the wiring is done. You're almost there! Now it's time to get acrylic-y!

Step 14: Soldering the Sensor and Channeling the Charger

The last soldering step is to wire up the sensor to the Arduino and the power wires we soldered earlier to the PCB.

  1. Install the UV sensor in the hole in the top lid of the enclosure.
    • The order is screw>plastic windowpane > enclosure > sensor fit into the window > nut.
  2. The wires are routed through mini cable clips glued to the underside of the enclosure top down to the opposite corner, then down beside the large standoffs that secure the two halves of the enclosure together. A third cable clip keeps the wires in place near the standoff
  3. Add heat shrink to the ground and power wires, and splice the two together (cut off any extra connections you made back in the breadboarding stage, so you only have one splice)
  4. Insert the third/center sensor wire into the A1 pin slot on your Arduino, and you're ready to read those rays.

The last mounting step is to mount and route the solar panel and its wires.

  1. Push the solar charger wire through the hole in the lid.
  2. Screw the panel to the lid via the included flat plastic washers.
  3. The solar charger wire is then routed through cable clips, down beside the standoffs OPPOSITE the sensor wires via another clip, and plugged into the jack on the solar charger circuit board.
  4. You're ready to unleash the power of the sun!

Step 15: Adding the Acrylic

Set the project enclosure aside for a moment, and grab your cork backed ruler, your acrylic cutter, your tape, your sharpie, and that thin sheet of acrylic. Now we're going to make the window that protects the UV sensor on top of the beach buddy, as well as the acrylic panel that protects all the delicate circuitry from your inserted cell phone and phone hookup wires.

The Window:

  1. Using your ruler to make a straight cut, score the 8x10 sheet of acrylic lengthwise, to get a strip of acrylic about 3/4" - 7/8" wide and 10" long.
    • Leave the protective plastic sheet on the acrylic while you're scoring it.
    • Once scored 10-15 times (you're getting little plastic ribbons), align the score line with the straight edge of a table or countertop, clamp the acrylic in place (bigger piece hanging over the edge), and apply pressure to the larger half to snap the acrylic cleanly in two.
  2. Wrap the end of the acrylic strip in painter's tape a few times; because this sheet is so narrow, the cut will need extra reinforcement against cracking.
  3. Clamp the narrow strip of acrylic down (pic 1) and score across the width of the strip, to get a little square about 1 1/2" by 7/8" (pic 2).
  4. Remove all but the protective plastic sheeting from the little square. Hold the little windowpane over the hole where the UV sensor will sit, and using a Sharpie, mark where the hole will be (pic 4)
  5. Re-wrap the windowpane a few times, being careful to re-mark the hole after every layer of tape.
  6. Clamp the window back down (not shown in pic 4), and CAREFULLY SLOWLY AND GENTLY DRILL a 3/32" hole in the place where you've marked.
  7. Go slow! Doing so is the difference between cracking the plastic, and getting a clean hole. The cracked plastic in pictures 5 and 6 resulted from going too quickly with the drill, and not taping the acrylic up sufficiently.
  8. Once you've got a clean windowpane, gently file the edges smooth and the corners round.

The Panel:

  1. Using the remaining 8"x9" sheet of acrylic, lay it over the top of your enclosure and mark where to trim it down, so it fits just inside the lip of the enclosure.
  2. Trim the acrylic to fit, following step 1 described above. (You may need to use your needle nose pliers to grip the small strips of acrylic and snap them off.)
  3. Once trimmed down and filed, set the acrylic inside the lip and mark where the enclosure's plastic standoffs are.
  4. Repeat steps 5-7 above to drill two 5/16" holes in the plastic at the corners on one broad side of the enclosure.
  5. On the other corners, score the plastic at an angle, to both fit around the standoffs and allow cords to be run through.
  6. Check for fit, then file the edges down/smooth
  7. Once the outer edges have been cut, tape up a strip near the opposite end of the panel where your phone-hidey-hole will be. Drill one hole for the headphone plug, and one hole for the USB plug (pic 7).
    • The headphone jack hole is about 3/8" here, the plug pulled through from underneath.
    • The USB hole is just over 1/2", filed larger - the actual USB end is threaded through from above and connected to the Mintyboost, rather than trying to fit the 30-pin iPhone 4S connector through the hole (pic 8).

Give the acrylic a quick cleaning with a multi-surface cleaner and paper towels, then install the panel as shown in pic 9. Be careful not to pinch the sensor and solar charger wires in the corners!

Step 16: Wrapping Up and Optional Last Steps

WE MADE IT! The end is in sight!! You'll be sunbathing in no time!

Carefully feed all the wires into the space beneath the acrylic panel as you guide the top into place over the circuitry.

Before you screw the top in place, do a systems check to make sure everything is functional.

  1. Check to make sure you can play and hear music through the speakers when your phone is plugged in via the headphone jack and the music switch is 'on'.
  2. Check to make sure your phone shows 'charging' when the 30-pin cable (or lightning, or microUSB, or whatever) is plugged into your device and the charger switch is 'on'.
  3. Check to make sure the LCD lights up, displays and cycles through the menu with button pushes, and makes reasonable calculations based on every input.

If all three systems are functional, take a deeeeeeeeeeeeeeeEEEEEEEEEEEEP breath and screw the four silver screws in that came with the enclosure, securing the box closed. Add the little plastic screw covers, and that's it.



Oh, but one last little thing:


If you decided to label the enclosure, as I did, simply follow the steps on the outside of the rub-on decals package to label buttons, mark switches, and even name your project. (Be advised; without proper sealant, these decals will rub right back off with more than one use of the button.)

Step 17: Final Thoughts

The Beach Buddy was originally intended to also possess a 'timer' function, but due to my limited abilities with Arduino, I was unable to get that code to work with the code I'd managed to cobble together and get functional.

The plan was to link a Piezo buzzer to the Arduino, and simply have an alarm go off once the timer, calculated based on user input, hit zero.

If, by chance, an Instructable user more versed in code than me should happen to make this device and to incorporate a "timer-based-on-input" function into the code, please comment on this Instructable, message me, send a carrier pigeon, etc! I'd love to get the Beach Buddy to do what it was originally designed to do, and feature your update to this project!!

But, for now, this is starwisher signing off. Thanks for taking a look at my project, and I hope you enjoy your Beach Buddy just as much as I've enjoyed mine!

Now if you'll excuse me, there's a frozen Mike's and a lounger calling my name.

squeeze more awesome out of summer contest

First Prize in the
squeeze more awesome out of summer contest

Summer #mikehacks Contest

Participated in the
Summer #mikehacks Contest