A funny story about multi sourcing components and the importance of testing before shipping!
I used a supplier on Aliexpress to purchase a few thousand switches in a few orders over a few months but their prices went up quite drastically after the last order (doubled!!) they weren’t the cheapest to start with but were reliable and friendly, worth the extra ££
I found another supplier who did a good deal for a full bag of 4000! Ordered them and waited, very quick delivery and friendly also (will buy again!)
I built my first test new keyboard with the new PCB and switches
It didn’t work. Well, actually, it did! Work perfectly…but in reverse :-p …..
If you mashed every key simultaneously then only released the key you want to press….it worked!! Yeah, the supplier sent me 4000 ‘inverted’ switches! My fault for not checking prior to ordering, they ‘look the same’ so ‘must be the same’ was a wrong assumption on my part! (At least they all weren’t the shift lock type!!)
It’s a VERY easy fix though (found after several panicked hours of testing and building Keyboards)…rotate the switch 180 degrees and it’s perfect!
In each kit I’ve included a small errata note and list of basic instructions to help. It’s an annoyance but for you guys it really just means the silk screen doesn’t quite match the switch orientation so just ask first. Look at the pictures and of any doubt, email/messenger/twitter/Reddit me 🙂
Some quick steps right now – photos to follow.. Suggest have two tabs open, this one and the other PICTURES tab for reference
Some videos are up on youtube also
SUMMARY- SOLDER PARTS ONLY IN THIS ORDER
Cut one leg shorter on the diodes – Use scissors . About 1-1.5cm is good
bend the short leg side to a right angle
Note the orientation of the diode – The F Key diodes have a diode picture on them. The white bar matches the location of the black bar on the diode.
put diode in holes and bend slightly to lock in
repeat for all diodes
Solder all diodes
clip the excess legs back
you have a few spare diodes so don’t be afraid to experiment on one or two to get the right bend / fit
Probably best to solder these in now before you forget
I’ve found it useful to PLACE the arduino on the headers (DO NOT SOLDER YET) so it keeps the headers parallel
Make sure the black part of the headers is on the underside of the PCB
Solder one pin of each header
SWITCHES – STEP 1, JUST TACKING IN PLACE
Pay attention to orientation
don’t worry about straightening the switches at this stage, the goal is to just ‘tack’ them in with a single solder blob to hold them in place. They can be wonky, it doesn’t matter.
DO NOT SOLDER MORE THAN 1 PIN OF EACH SWITCH IN ONE GO
The switches are easily heat damaged – they become ‘sticky’ and no longer move smoothly if the plastic is melted due to excessive heat. During the entire soldering procedure for the switches, do ONE leg, move to the next switch. when all are done, move back to the first switch and repeat.
I’ve damaged only 2 switches this way soldering the prototypes but it can happen if you’re not careful
Note that the white part of each switch is asymetrical. One side has a ‘dip’ / inset which guides the switch up and down. the other side is smooth
there’s a marking on the PCB to represent this dip / inset.
ALL switches go the same way
Get a sheet of paper
Insert the top row of switches into the PCB
Place PCB on sheet of paper and fold paper over the top, tightly
flip the PCB over
hopefully all the switches stay in place
Solder just ONE leg of each switch – any one – say the top right
Repeat for Row 2
DO NOT FORGET TO SOLDER THE ARDUINO HEADERS IN PLACE
Repeat for Row 3
DO NOT FORGET TO SOLDER THE ARDUINO HEADERS IN PLACE
Repeat for for row 4
(Hopefully you didn’t forget to solder the Arduino headers in place?)
and finally the space bar
SWITCHES – STEP 2, Straightening
This is probably the most important step to getting a good looking keyboard with all the switches aligned. Spend some time getting this right, you have a handful of ‘spare’ switches so now’s the time to make mistakes and fix them whilst there’s only a single solder blob on them
I’ll post a few videos shortly but there’s a technique.
Hold the board in the air
Use your index finger to push in, and slightly down on each switch whilst soldering the previous blob. The goal is to move the whole switch slightly so that it’s slightly at the top, or the bottom of its footprint.
when you melt the solder whilst pushing in and down, the switch will move slightly, sometimes you’ll hear a little click or snap as the solder melts
repeat this for each switch, pushing in and down slightly – when you look at the final position, there’ll be some of the pad visible at the top of each switch
NOW IS THE TIME TO TEST EACH SWITCH FOR SMOOTH MOVEMENT
of the 5 keyboards i’ve soldered, I’ve had two defective switches, this is partly the reason why there’s a few extras in the kit
of the 5 keyboards i’ve soldered, I’ve broken 3 switches by either over-heating, or trying to remove after putting them in backwards. unless you’ve got a hot air gun, they’re tricky to remove intact, hence check NOW whilst there’s only one solder blob!
When you get close to one side of the keyboard, you’ll have to fiddle a bit to keep pushing the switches in the same direction. I’ve found that changing technique a little and ‘flip’ the board lengthwise works. hold the board against yourself and use your thumb to pull the switch down instead of push
repeat the alignment technique for ALL switches!
SWITCHES – STEP 3, Final soldering
This is the easy / relaxing bit!
DO NOT SOLDER MORE THAN ONE LEG OF EACH SWITCH AT A TIME
do it by rows, clusters, however works for you, but here’s what worked for me
Solder ONE pad of each switch, then move to the next
once all switches are done, start from the beginning
Solder another pad, etc etc
A SMALL CHEAT – You only actually need to solder 3 points. Two on the ‘bottom’ of the switch – these are the electrical contacts. ONE on the ‘top’ – this is for mechanical stability. As you look at the keyboard, the bottom two pins are the important electrical ones. Pick any on the top
on my prototype, I found soldering all 6 pins tiring, so on my second version I just soldered 3 and it worked perfect. Up to you, but DONT SOLDER MORE THAN 1 PIN AT A TIME
Note the orientation of the Arduino by the Small USB socket and a mark on the PCB. Also the silk screen on the PCB will match the letters on the Arduino.
these need a little more heat to solder to the pins