Instructions for assembling your PCB

Things you’ll NEED to assemble your PCB:

  • Soldering iron + sponge (I like the brass wire sponges)
  • Solder
  • A snips tool / scissors that can cut thin wires

Things that will help:

  • Helping hands, the little clamps to hold your PCB securely
  • Blue painters tape to hold pieces in place when upside down
  • Hot glue to secure your LED output wires AFTER soldering
  • Wire strippers

Instructions

* Please be careful when assembling this PCB, and please read the full text for each step before doing it. *

Place your Aux jack in it’s spot and solder 1 of the leads. If it moved while soldering, you can heat that up again, shift it back in to place, and then remove heat. Solder the rest of the leads. Be careful not to add too much solder to the 2 pins closest to the front, as solder will travel up in to the jack and make it hard to plug an Aux cable in.

Push the 3 buttons in to their spots. Sometimes they snap all the way in without a problem, sometimes they are nearly impossible to get all the way in… When pressing it in, try to apply force down and backwards, so that it doesn’t tip forwards. If that happens, just bend it back though. As long as you can get the 2 smaller pins at the front to poke through the tiniest bit, that’ll work. Those are the only ones you will solder.Fold the resistor wires like the in the picture below and place those in. Direction does not matter. Then place the DC barrel jack in its spot. If when you flip over the PCB to solder, the barrel jack falls out, hold it in to place with tape. Solder the resistors and power jack in place. Fold up the extra resistor wire and snip it off. KEEP 4 OF THOSE WIRES FOR LATER.

To get the long level shifter chip in place, you have to bend all the pins inwards. The picture below shows how to achieve this. Pinch both sides, and press all the pins down on the table until you can feel them bend a little. Repeat for pins on other side. Try placing in the PCB and if needed, bend pins more. It’s easier to bend them more than unbend them!

Then solder the chip in place, and you only need to solder the pins with the little white arrows.

Place the DC converter on the PCB. It should fit in the white rectangle that’s there for it, as in you should not be able to read “DC Converter” once it’s in place. You can just place the PCB upside down on your table to solder this in place or use tape if you’d like to use your helping hands.

Create the full Teensy 3.6 + Audio Adapter stack, including the 14 pin headers. Make sure it’s all pressed together, with no gaps between the stacking pin dividers and the Teensy/audio adapter.

Place it on the PCB and solder the pins on the top of the audio adapter.

(If you want to save time/solder, you can just solder the pins in this picture. Otherwise, just solder them all. If you only did the required ones and later on your audio input isn’t working, double check the pins you soldered.)

Flip¬† the PCB over and solder the header pins on to the PCB, where you only have to do the ones with a white arrow. You’ll see I use the helping hands here to hold down the PCB since it won’t sit flat. If you don’t have them, one solution is to solder 1 pin with it tilted. Then you’ll have another hand to press it flat while you reheat that solder joint.

Pull the Teensy/audio adapter out of the header pins you just soldered to the PCB. Secure the Teensy/audio adapter upside down in helping hands / a clamp, and either solder all the pins or just the ones in the picture below. MAKE SURE YOU ONLY USE AS LITTLE SOLDER AS NECESSARY ON THIS STEP. TOO MUCH WILL PREVENT YOU FROM PRESSING THE TEENSY FULLY IN TO THE HEADER PINS. IF YOU HAVE THICK SOLDER, BARELY TOUCH IT TO THE PINS WHEN SOLDERING. Pro tip, keep your soldering iron in contact for an extra second to let the solder settle downwards.

(It’s a little risky to solder only the pins you need, because if you miss one, things could act funky and hard to troubleshoot. If you do though, make sure you solder all the pins that were required on the audio adapter, and all the pins that were required on the bottom of the PCB.)

This isn’t a great pic, but it shows how little solder you need. Try not to make it a big bubble of solder going up the pin.

Now let’s solder on the microphone. PJRC includes this white piece of plastic to keep the microphone’s metal can from touching components on the audio adapter, so place the 2 mic pins in to the plastic as seen in the pic.

Then place it in the audio adapter, flip it over, and solder those pins. The microphone’s pins won’t poke out of the holes much, but you should see them inside the holes.

Turn your Teensy upright, so it’s standing on it’s pins. Now take 3 of those extra resistor wires you clipped (any ~20 gauge solid wire works as well), and place them down through the holes for the “line in” pins. You only have to do L, R, and 1 of the Gs. Then bend over the top of the wire going through G and solder it to the other G hole like in the pic below.

Then place the 2 2-pin header sockets between the 14-pin sockets and Aux jack. Plug the Teensy in, guiding those 3 wires you just soldered in to their sockets below. This will hold the 2 2-pin headers in place so you can flip over the PCB and solder those in.

Place the 15-pin header sockets on the ESP32 and place that on to the PCB. Flip it over and solder the pins. You can only solder the pins with the white arrows if you want.

You can see in the pic above I used the foam from the microphone’s packaging to prop up the PCB.

Now place the capacitor in to its pins. MAKE SURE THE NEGATIVE SIDE (SHORTER LEAD AND GREY MARKING) IS NEXT TO THE ESP32. IF YOU GET THIS WRONG, IT WILL EXPLODE.

Bend the wires flat against the bottom to keep it in place, flip it over, solder, and cut the extra wire off.

The next step is to fix an error when the PCB was manufactured. I’m still trying to figure out why this happened, because it all looks right on my end. The issue is that the GND pin on the button closest to the AUX jack is not connected to GND. To fix this, we just need to jump it to another GND pin, and the closest one is the button next to it. Take a wire that you just cut off from the capacitor or the resistors, bend it in to a “u” shape, and place it on the PCB like in the picture below. Solder 1 of those, then make any adjustments necessary, and solder the 2nd one.

The last step is to solder on your LED output connector. There are 3 locations for LED outputs, meaning you can make 3 LED strips do different things. You’ll see the 3 resistors have labels like “OUTPUT x,” because each resistor is connected to an output. When using the OCTOWS2811 library, the outputs are set up to be pin 2 first, pin 14 second, pin 7 third. Pin 2 goes to the middle LED output, pin 14 goes to the output under the Teensy, and pin 7 goes to the output under the ESP32. If you’re only driving 1 LED strip, solder it to the middle one with the resistor labeled “OUTPUT 1.”

MAKE SURE YOU SOLDER THE + AND – CORRECTLY. On the bottom of the board, you’ll see a wide trace connected to each output, which is the +. It’s also labeled on the top of the board. If you’re LEDs only have 3 wires, the middle one can go in either of the middle holes, but the + and – need to be on the outside holes in their places.

For this part, I sometimes use a wire stripper to make more of the connector wire bare, which makes it easier to solder into the through holes. You’ll see in the picture below, I used a snips tool to pin down the wire, and the helping hands to keep the PCB from sliding away.

If you did use wire strippers, make sure there are no frayed wires from 1 touching another.

At this stage, you’re done! But I recommend adding hot glue around where these wires touch the board. This will keep them from bending repeatedly and snapping.¬† However, before you hot glue, test it to make sure that output is driving LEDs.