Full Build Instructions for pi-Stomp Core (most recent version 2.0.4)
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. It's very difficult to unsolder a multi-pinned part like a header or jack without harming the board or part. If it becomes necessary and you find it difficult to unsolder a part, it's often best to just sacrifice it by cutting its leads then clearing the holes for a new part.
If you choose to go FULL DIY and ignore the following instructions, please at least view the photo depicting each step (click on any photo to enlarge it) 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.
Some steps have options to allow for system customization. Those are tagged with a question mark icon:
It might be a good idea to consult the Customization guide
and consider your customizations prior to building.
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, post to the build forum or email: firstname.lastname@example.org
It's advised to have the BoM pi-Stomp Core 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 and was chosen to facilitate assembly. Could be helpful to check off each part in the BoM, once it's installed.
Keep your tip clean using a wire sponge or damp sponge or both. Oxidation (black stuff) prevents heat transfer and can result in cold joints. I suggest wiping it at least every 4 or 5 joints and definitely once when you're finished with a round.
It's tempting to just feed the solder into the iron. The flow of the solder follows the heat, so heat the pad and component lead for a second or two, THEN feed the solder into the junction. If the solder doesn't melt, pull the iron away and melt a dab of solder, then go back to heating the junction.
Don't apply too much solder (see guide below). Almost as soon as it flows, I stop feeding. Small diameter solder is recommended (0.8mm / 0.031“).
Keep the iron on the joint for a second or so after the solder flows.
Don't keep the iron on the joint any longer than necessary. Excessive heat can damage components.
Good idea to inspect your soldering under magnification to assure you didn't bridge short any pads. The headers with 0.1” spacing are especially prone to this. You can check for shorts using a continuity meter. 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, IC's, etc.) are easily detachable. So if you mess up the board, a lot of the parts can be salvaged. If you're stuck with a build mistake, post to the build forum
, or contact email@example.com for suggestions.
All Set? LET'S BUILD!
Step #0: Software Engineers start counting from Zero
Before you commence building, it's highly advisable to consider how you plan to mount your pi-Stomp. Specifically, you should decide whether you plan to mount top-mount the LCD above the enclosure face, or under-mount it. Your choice will affect Step #9 whether to install the LCD header or not.
Check out examples of top-mounting and under-mounting methods here
Under-mounting looks far more professional and better protects the LCD. But it requires being able to cut a rather sizable rectangular cutout where top-mount just requires a simple slot. Another disadvantage of under-mounting is that you cannot socket the LCD, it must be soldered to the pi-Stomp board because no socket exists short enough to allow the LCD face to sit below where the volume pot and encoder end up. One could avoid mounting the pot and encoder and flywire them to the board, or use a 9-pin ribbon cable to place the LCD away from the pi-Stomp board, but those are specialized builds not covered here.
Below are the parts needed for assembling the pi-Stomp Core PCB. If you seem to be missing some, make sure you look in the Rasberry Pi box.
To save you from the often frustrating soldering of surface mount components, we've presoldered the voltage regulator for you. You're welcome!
Step #1: Install Resistors
Bend the legs and insert all resistors R1, R2, R3 & R4 (2Meg) from the silkscreened side.
Splay the leads slightly to keep them positioned
Repeat for R5 (33 ohm - orange/orange/black/gold)
R6, R7 & R8 are only required if you're going to be using the extra 3 GPIO pins (for LED's, etc.) and require a voltage drop / current limit. Calculate the value as appropriate for your load or add a simple wire jumper if you're using the GPIO as an input.
Step #2: Install Capacitors
Insert C1 and C2 (red 0.1uF), splay leads (non-polarized)
Insert C3 and C4 (smaller yellow 0.1uF), splay leads (non-polarized)
Using needle nose pliers, straighten the pre-bent leads for the 10uF oscon capacitor C6
and insert. Make sure the negative lead, marked with the blue paint, goes thru the hole marked with “-” (also has a square solder pad)
C5 is optional. 10uF or greater if ripple is a problem.
Step #3: Install Fuse and Transistors
Insert both transistors (Q1 & Q2) with the flattened side matching the silkscreen. Splay the leads, solder, trim. Too much heat can damage a transistor, don't linger with the iron. If you can't solder in less than 3 seconds or so, attach a heat sink tweezer to the transistor side of the lead.
Pay close attention to which side the header should be inserted - the side with the silkscreened name. Unsoldering a misplaced header is not fun.
It's important for headers to sit tight and perpendicular to the board (except where noted otherwise). I use tape to keep it in place until a pin (or two) is soldered, then adjust as necessary before soldering the remaining pins
HGPIO (2x3 Male 90 degree)
This header is optional but recommended if you might need access to extra GPIO pins for Outputs (LED's, etc.) or direct (not ADC or debounced) inputs.
This header can be installed on either side of the board. If you do mount it on top (side with the volume and encoder), angle the pins slightly upward (maybe 10 to 15 degrees) so that jumpers can be attached and clear the IC which will be installed South of it later.
The bottom side (side with header silkscreen and the red capacitors), is generally recommended and shown in this build. Angling the pins slightly upward just a few degrees can make it easier to attach jumpers.
Secure at both ends. Perpendicular as possible to the board..
Solder. The 40 pins are rather close and solder bridges between pads would be bad, so take your time and don't over-solder
HOut (1x2 Male) and HIn (1x3 Male)
These are the headers for the output and input jumpers. When complete they should look like this:
Note how the black plastic ends up perpendicular to the board not flush to it.
Use tape to secure each while soldering. It can help with positioning if you attach a jumper as it will be when eventually connected.
HExt (1x26 Male)
This provides the interface for attaching, switches, MIDI and analog inputs.
To allow best access to these pins when the whole board sandwich is assembled, make sure the pins are not angled inward but either straight up or maybe just a few degrees outward (away from the board edge)
Step #5: Install Sockets and Relay
The sockets have a notch to indicate pin #1. Orient that to match the silkscreen notch.
S2 (the ADC socket) is recommended for most builds unless you plan to replace the ADC with your own hardware connected via SPI (see the Customization guide)
Step #6: Install Jacks
Make sure these are inserted from the correct board side. Unsoldering them is a bitch.
To increase mechanical sturdiness, before soldering, bend over terminals with a blunt, plastic utensil (eg. butt end of a Sharpie).
Step #7: Install Pot and Encoder
Vol pot P1 has a “keying” tab (unless it's already been removed) which, although is less than 1mm tall, will prevent the pot from sitting flush to inside face of the enclosure when mounted. It's important for it to sit flush. You can either file the tab down, or break it off with needle nose pliers. Because filing makes a mess, I prefer to break it off.
The last part is often the trickiest. The encoder Enc has very short pins, but for it to sit tight against the enclosure face, it (plus the included nylon washer) needs to sit at roughly the same level as the Vol pot. It should rest on its side tabs at the appropriate level, however, it can rock and end up not perpendicular to the board. So…
Solder just one of the 5 pins. Because of the short pins, you may need to solder from the top (encoder side) of the board.
Make sure it's still as perpendicular as possible. If not, adjust. Reheat the solder if necessary. Once it's good, solder the remaining pins.
Solder the side tabs to the pads on the top of the board (for mechanical stability)
The board now looks like this
Step #8: Add IC's
The pins of the IC's usually need to be bent inward just a millimeter or two before inserting. Lightly squeeze all pins between thumb and first finger.
All IC's are polarized. Make sure the notch/dimple (indicating pin #1) ends up on the same end as the silkscreen (and sockets if you installed them right). Worse case, match the photos below.
Step #9: Attach the LCD
Depending on how you plan to enclose the pi-Stomp, you need to decide whether to Top-mount the LCD and install a header (HLCD) for it, OR Under-mount the LCD and solder it directly to the board. Under-mount will generally be the most professional looking. See Enclosure Considerations for examples.
Top-Mount instructions using a header
All others, and especially if you purchased an enclosure from Treefallsound, should use Under-mount shown below
Under-mount the LCD...
A header for easy removal of the LCD (as used in Top-mounting) isn't possible for under-mounting. It would result in a height inconsistent with the encoder and volume control. So for this method, you'll be soldering the LCD directly to the board.
Three spacers HW23 - HW25 (5.5mm tall) can be glued between the pi-Stomp board and the LCD to keep it parallel and at the right height - just below the enclosure face when the volume pot and encoder are mounted.
You'll want to place the spacers so they're flush against the boards, between solder pads. Could require a bit of test fitting, but if you place them as shown, it should work fine.
A light layer of hot glue affixes the spacers and breaks fairly easy if you get it wrong.
Because the LCD, once soldered, will obscure the audio input header, you'll need to connect W2 (4“ 3-wire jumper which will eventually connect to the Audio board) before attaching the LCD, Each pin is labeled on the board with “L” for left, “G” for ground, and “R” for Right. Once you connect the jumper, make note of which color connected to each pin. In the build shown: L=Yellow, G=Green, R=Blue.
A spot of hot glue can keep the jumper from separating from the header
Now insert the 9 LCD pins, securing the LCD with a bit a glue on at least 1 spacer. If you glue all 3, you'll have to work fast before the glue dries.
Flip everything, and solder from the other side
The pi-Stomp board is now complete.
Step #10: Prepare Boards for Assembly
The kit comes with 4 sets of standoffs (spacers) and screws. Each are a different height so it's important to use the correct ones.
Add spacers to the pi-Stomp Board
To either side of the 40-pin header, we'll add a 12mm spacer plus 1mm washer for a total height of 13mm
Insert a screw from the “top” side, then from the “bottom” add a 1mm washer, then the 12mm spacer, then tighten.
Prepare the Audio Board
Attach two silver 11mm metal spacers using two screws to the Audio Board
They should attach to the “bottom” side on the edge opposite of the 40-pin header
Prepare the Hat Hacker
Attach two 8mm nylon spacers, plus 1mm thick washers (9mm height total) using two screws to the Hat Hacker
They should protrude from the “bottom” side. Insert the screw from the “top” side, through the elongated hole (end nearest the 40-pin header) as shown, then add the washer and finally the 8mm spacer.
Prepare the Raspberry Pi
Attach heatsink to Broadcom chip on the “top” side. Peal just the blue layer of the tape, then stick it on the chip and press firmly.
Attach a second heatsink to the CPU on the “bottom” side.
Step #11: Stack the Sandwich
First, the Audio Card onto the Hat Hacker
Leave the sticker on the board. That along with some fingernail polish under the sticker are in place to prevent possible shorting to the volume pot on the pi-Stomp circuit board.
Seat the 40-pin header completely and attach with two screws
Next, the Hat Hacker onto the back of the pi-Stomp board
Seat the 40-pin header and attach with two screws (note that there will be a slight ~1mm gap between the headers)
Flip the board and attach the audio jumpers. The input pins shown in green should match the “L” “G” and “R” wire colors you noted when connecting the other end. The output pins shown in pink should match the “L” and “R” on the pi-Stomp board. Note there is no ground for the output connection.
Next, the Raspberry Pi board will be attached to the Hat Hacker
Seat the 40-pin header and attach with two screws
Your pi-Stomp Core is now complete!
Other views of the final stack:
For installing into an enclosure see this example:
Example build into a 1590J enclosure