Full Build Instructions (pi Stomp! 1.0.1)

Do not use these instructions unless your board has “pi Stomp! 1.0.1” silkscreened on its back side

Do not attempt to build this if you are not already comfortable soldering printed circuit boards. This is a rather advanced project, not intended for beginners

Tree Fall Sound cannot be held responsible for any damages or injury which may result during assembly or usage

Tree Fall Sound cannot be held responsible if your build does not function as expected

pi Stomp is not a “kit”. We've tried to identify and iron out potential build issues, but you might encounter your own. Identifying a problem and figuring out a way to fix it is part of the fun of DIY. That said, if the instructions aren't clear, you run into problems or just have questions, please email: support@treefallsound.com

If you choose to go FULL DIY and ignore the following instructions, please at least view the photo depicting each step (click on it to enlarge) and read any instructions with bold text or a warning icon: . These are critical steps, or steps with quirks which might cause issues if not performed as suggested.

It's advised to have the BoM Full Bill of Materials handy (either open in a browser window or printed). The order of these steps roughly corresponds to the order of the BoM. Could be helpful to check off each part in the BoM, once it's installed.

Good idea to keep most parts in their labeled packaging until ready to solder. This is especially true for the resistors (unless you enjoy the sometimes maddening task of deciphering the tiny color codes on 6 band resistors).

All parts should be inserted from the side of the circuit board on which they are labeled (silk screened), then soldered from the opposite side. Installing on the wrong side, will cause problems, in most cases, Big problems. The “Top” side of the board will have the rotary controls, LCD, relays and footswitch resistors/capacitors. The “Bottom” side will have headers for the pi and audio card, all jacks, power and midi/ADC circuitry and the treeffallsound.com label.

Good idea to inspect your soldering under magnification to assure you didn't bridge short any pads. The three 40-pin headers with 0.1“ spacing are especially prone to this. Here's an excellent guide to identifying other solder joint issues: Adafruit soldering guide - common problems

Take your time! A rushed job during assembly could reward you with many hours of debugging later, or worse, a high tech doorstop. The possible bright side there, is that it's a fairly modular design and the most expensive components (Pi, LCD, audio board, switches, LEDs, etc.) are detachable. So if you mess up the board, most of the parts could be salvaged.

All Set? LET'S BUILD!

Bend the legs and insert all resistors R1 thru R16 referring to the BoM for values and placing by finding the corresponding label on the board (bottom side for R1 thru R5, top side for R6 thru R16)
Splay the leads slightly to keep them positioned
Repeat for the single diode D1, but note that it is a polarized part. The black line towards one end indicates the cathode as does the corresponding line on the circuit board silk screen.

Solder all populated pads
Trim the leads using diagonal cutters

Insert the Debounce Capacitors (C1 thru C5), from the top. These caps are non-polarized so orientation does not matter. Splay the leads to keep in place
Solder and trim leads

Insert electrolytic capacitor C6 from the bottom. Make sure the negative lead of the cap goes thru the hole marked with ”-“
Solder and trim leads

Attachment of the Audio Board (Audio Injector Zero) requires 6 total headers. The alignment and soldering of the headers can be facilitated by making a “sandwich” of the two boards with headers between and securing with screws before soldering. Not doing it this way or similarly, can result in a board which is difficult or impossible to attach to the main board. Note that your hardware might be a different color than shown.

Add HW4 and HW5 8mm nylon standoffs (the short ones) to the bottom of the Audio Board, attach with HW1 and HW2 screws

Mate H1 & H2 3-pin female headers with H4 & H5 male headers. Note the male pins have a short side and a longer side. Mate the short side

Set the long pins (male) of both of the header stacks into the H4 & H5 locations on the board

Set the 2×20 male header H6 into place - also with the long pins into the board (short pins up)

Now the tricky part. Set the Audio Board onto the 2×20 header and wiggle the 3-pin header stacks until all pins are going thru each board

Squeeze the whole sandwich together, and secure with the two threaded standoffs HW8 & HW9

Once everything looks tight, solder the 3-pin headers from the Audio Board side.

Flip the board and solder the pins of the 2×20 and 3-pin headers. Given the long length of the pins, avoid using too much solder

Once all pads are soldered, un-screw the two protruding nylon standoffs, and un-plug the Audio Board (to give access for the next step)

It is critical to orient these parts correctly. The silkscreen indicates the correct orientation

All of these parts are more sensitive to heat than others. Don't linger with the soldering iron

Some parts will stay in place when you flip the board, others might require that you bend over a couple leads.

From the top side:

Insert both transistors (Q1 & Q2) with the flattened side matching the silkscreen. Splay the leads
Insert both relays (Rly1 & Rly2). The end of the relay marked with a line should go towards the relay ID label

Flip the board and solder all pads for the 4 components. Trim transistor leads.

From the bottom side:

Insert the Midi IC (U1). It's likely to have a dot indicating pin 1. That corresponds with the square pad and part ID label. Some versions might instead have a groove or stripe along one edge in addition to or instead of the dot.
Insert the ADC IC (U2). Orient so that pin 1 (notch or dot) corresponds with the part ID label

Flip board and solder all pads for the 2 components

Step #5: Install Remaining Headers

Insert the right angle pins of the 2×6 header H8. The black plastic should be perpendicular to the board not parallel

Flip board and solder all 12 pins

Insert tall (8.5mm) 2×20 female header H7.

Flip board. To keep the header tight to the board, bend over (outward) a pin from each end using something plastic like the butt end of a Sharpie. Solder just those two pins. The open back of the header can allow solder to flow from the pad side and clog the header socket. Very Bad, can ruin the whole project. My remedies have been to use as little solder as possible for the 40 pads, and to actually plug in the Raspberry Pi once you have the two pins tacked. The pi's pins will keep the sockets full so they won't clog. Now solder the 40 pads.

Unplug the pi once all solder is cool.

Insert male header H9 for the LCD (short side of the pins into the board). Flip the board. The header must remain flush to board. Resting the board on your work surface should push it into the board, if not, use tape to keep it in place.

Solder all 40 pins

Insert the white molex male header H10 The orientation is critical. Make sure the slots face the nearest board end.

Flip board to solder, if it falls, keep in place with tape

The height of the LCD, pots and encoders off the board will eventually determine how level the board sits inside the enclosure and how well the parts protrude thru there respective holes.

From the top side of the board, insert the Volume pot P1
From the bottom side, bend over the side tabs to keep it in place while you solder (don't use anything metal to do the bending or risk scratching the board. Butt end of a sharpie works well)

After soldering one terminal or tab, check that the pot is flush and perpendicular to the board. If not make it perpendicular, unsoldering if necessary.
Solder the remaining terminals and support tabs
Repeat for the Tweak pot P2

Although the pots and LCD should naturally end up about the right height, the tolerance for the encoder height is tight because of its very short terminals. The ideal height of the LCD board top, the pot bodies and encoders bodies (with a washer) is just about 10mm.

If an encoder sits too high (over 10.3mm), the terminals won't make contact with the pads on the board. If it sits too low (below 9.7 mm), the shaft threads won't protrude from the enclosure enough to attach a nut. The side support tabs on the encoder set the height and need to be slightly bent. If you bend them as below, you shouldn't need to measure

With a pair of needle-nose pliers, bend the very end of the tabs to be “L” shaped (like the encoder on the right)

Insert encoder Enc1 so it sits on its tabs. Make sure all 5 terminals descend about half way thru the thickness of the board and the shaft is perpendicular to the board. If not, bend the support tabs accordingly. Keep in place with a long strip of tape (or other clever means) until you have at least one terminal soldered

Unlike all other components, solder from the TOP (because the terminals won't protrude enough on the back side)
After soldering the first terminal, recheck that it's still perpendicular to the board. If not, make it perpendicular before continuing
Solder the remaining terminals. Solder the side tabs for stability.
Inspect the pads from the back side. If solder did not flow to the back, you can add some from the back.
Repeat for Enc2

Make sure each jack sits flush against the board.

All 6 jacks are inserted from the bottom side of the board. Wait until you've inserted them all before soldering.

Starting from the Right…

Insert 1/8” TRS jack J1

A slight modification is required for the MIDI jack J2 to assure the enclosure lid will not be hampered. Using a utility knife (or sharp scissors), shave off the top 2mm of the jack face

Insert MIDI jack, to keep in place and add stability, use a blunt plastic object like a sharpie to bend over the two front pins

Insert the four 1/4“ jacks J3 thru J6, bend over two pins of each jack (diagonal from each other)

When all 6 are in place, it will look like this from the bottom side of the board:

Flip the board and solder all terminals for the 6 jacks. Some of the pads are very close to each other, make sure you don't short them together.

Plug-in the Audio Board (bottom side), secure with the standoffs (HW8 & HW9) as before

Attach HW10 (10mm standoff) to the main board with screw HW3 next to the Pi header H7

Don't install the Raspberry Pi just yet.
Attach HW7 (8mm standoff) to the main board with glue or double-faced tape, there is a hole there, but it is obscured from the bottom. The role of the standoff is not to secure the LCD, but to serve as a spacer.

Plug-in the LCD (top side). Leave the protective plastic on for now. Do not add a screw to the standoff since it would cause the LCD to not sit flush against the enclosure face.

Place the enclosure on edge, with jack holes facing up

Add a washer to each encoder shaft (encoder washers are smaller diameter than the pot washers)

Flip the board on edge, jacks up, add a stack of two plain black plastic washers to each 1/4” jack (note one of the provided washers is thicker and beveled, save that for the outside). Balancing act to keep all of those washers on!

Leading with the knob shafts and LCD, bring the board and enclosure face together. Hopefully everything aligns

Further seat the whole thing by attaching jack hardware (beveled washer and silver nut) and pot hardware (washer and nut). Likely best to lightly tighten each first, get everything looking fairly aligned, especially the LCD, then go back and tighten the hardware further. DO NOT Overtighten. Overtightening could not only break the part, but warp the board since there's kindof a tug-a-war between the jacks on the side and the knobs on top. If you do use tools, just a tad more than hand tight is probably enough.

The encoder shafts are short and it's possible that you won't be able to get a nut to grab enough threads. Not the end of the world, but try.

You should have a quad strip of female-female jumpers. Rip them by hand into two dual strips. Cut the connectors off one strip. Cut the other as shown

Cut the heat shrink tubing into 6 roughly equal pieces ~12mm (1/2“)
Split the conductors about 40mm (1.5”)
Slip a piece of tubing onto each
Strip about 7mm (1/4“) from each conductor
Twist copper strands and form a hook (with pliers) and attach to each switch terminal.

Solder each terminal (don't let the tubing heat up or it'll shrink prematurely - insert sophomoric joke here).
Once soldered, WAIT 2 minutes for it to cool
Slip tubing over terminals
Heat tubing using a heat gun (preferred) or a lighter. Keep the flame far from wire & tubing or else it'll melt or burn. Be patient, let the heat rise until the tubing shrinks tight to the terminal and wire

Repeat for the other 2 switches

The LED rings have similar lengths which determine their position. Start with the shortest.

Pass the leads of the ring from the face through the Left hole
Attach the LED connector to the Leftmost position (“L3”) of the board header, oriented vertically with the red wire connecting to the lower pin and black on top (ground)

Pass the shaft of a footswitch with one nut and lock washer on it from the inside through the hole and LED ring, secure with the second nut on the face
Attach the footswitch connectors onto the second Leftmost position (“F3”). Polarity doesn't matter for the switches

Repeat for medium length switch and LED ring. Note the alternating connection pattern from left to right: LED, Switch, LED, Switch, LED, Switch

Polarity is super important here, mistakes will be costly, so make sure yours looks similar the photos (except the presence of the “AltLCD” header which is not necessary for this build)

Mount the power connector J7 with the provided nut (orient as shown in the photo below for proper terminal identification)
Mount the power switch SW4 (“on” position towards you) pressing firmly into the rectangular hole until flush and the ratchets keep it in place

Prepare the power connector pigtail W4 as shown. Note the connector is polarized. Cut conductors to the lengths shown. Keep the excess red conductor. Strip all ends as shown.