Preparing LCD for v4.2 Installation
To produce a small finished product, the connection of the LCD to the HeaterMeter v4.2 board is done in a somewhat unorthodox manner. The LCD is mounted flush under the HeaterMeter PCB.
Step 1: Break off a 6 pin piece of pin header. Insert the long side of the pins through bottom left set pins from the front side of the LCD PCB. Flip the whole LCD over, set it on the table, and tack pin 1 in place with a small amount of solder.
The pins will fall out slightly, that's ok. You'll fix them on the next step.
Step 2: Lift up the LCD and heat that pin 1 solder joint again. When the solder is hot, apply a little pressure to the top side of the pins to push them into place. Remove the soldering iron and let cool before releasing the pressure.
Examine the LCD from the side. If the pins aren't more or less perpendicular to the LCD board touch that pin 1 again with the soldering iron and straighten them. Do this before you solder any other pins, or it will be very difficult to fix later.
Step 3: Solder pins 2-6 completely, then go back to pin 1 and finish soldering it.
Step 4: Using a small screwdriver or a knife, pry the black plastic retainer off the pins. Wiggle it up a little on each side until it comes off.
The height of the pins isn't terribly important but should at least 2mm but no more than 6.6mm.
Step 5: Solder pins 11-16 using the same procedure as Steps 1-4. There should be 4 unpopulated LCD pins in the middle.
Step 6: Check the height of your pins by trial fitting it through the HeaterMeter PCB and with the blue potentiometer inserted into the board as well. The pins should not extend past the height of the potentiometer. Check this before soldering either of the components to the HeaterMeter board.
Or just measure them like a normal human would. They need to be at least 2mm but less than 6.6mm. Simply clip any that are too tall with your wire cutters.
The LCD is ready to be installed and this short and simple process reduces the size of the finished device by more than 15%!