Need Electrical help (Soldering / Wiring)

Spoiler!

EDIT2:

Ok... apologies to anyone who spent time reading my post... I re-soldered (heated up, moved the pre-existing solder around a bit, applied a tiny bit of new additional solder) to my T switch, and now it works.... o___O so, conclusion is, something was indeed wrong with my solder joint, even though visually it looked fine, and a closed circuit SHOULD have been achieved regardless.... I'm still confused, and none of this makes sense to me personally. But I am glad it works now!

Thanks again!

09-09-2021, 01:43 PM	#1
PuYang I Will not Admit my Addiction to RS Join Date: Oct 2010 Location: Burnaby Posts: 578 Thanked 254 Times in 101 Posts Failed 6 Times in 4 Posts Member's Picture Albums	Need Electrical help (Soldering / Wiring) Spoiler! Hi, sorry, not sure what to categorize this under. I am at my wit's end! I am building a Hand-Wired keyboard, and am nearing the final stage, but ran into a few issues. I'm looking for feedback from people who know more about electronics, soldering, and wiring, etc, than I do. (I have 0 knowledge actually). Or have done hand-wired keyboards before (super niche, I know, so general electronic feedback is probably what I'm asking for). ----- For a little bit of context: 1a. Each key switch has 2 pins. One pin is wired along a ROW. And the other pin along a COLUMN. For example, keys QWERTY are on the same Row. 1QAZ are on the same Column. (These have been SOLDERED) 1b. A Diode is SOLDERED to one of the pins that leads to the ROW. (Switch > Diode > Row wire). No Diode needed for the other pin (Switch > Column wire) 2. The ROW and the COLUMN wires are then wired to the micro controller. (I did NOT SOLDER these wires yet). Each wire (in my entire build) are wrapped around their joint for 'decent wire on wire contact'. But I haven't soldered this step yet. 3. The micro controller has been flashed and confirmed working (bridging / creating a circuit on the inputs on the controller with a external wire simulates a keypress properly) I decided to test my keyboard before Soldering the Row/Columns to the controller. With the wires all making decent contact, I figure solder TECHNICALLY isn't needed? (correct me if I'm wrong). As a closed circuit is being made?? Ok, hopefully the above explains decently where I am at. NOW THE ISSUE: Plugging in the keyboard, everything works except for a few keys (T, 5, 7). And some keys work inconsistently (Y, DEL). (Pressing the keyboard switch doesn't trigger the keypress). Things I have tested / troubleshoot (For the T key): 1. Bridging or creating a circuit with an EXTERNAL wire on the Row and Column wires for the T key, does work and simulates pressing the T key. 2. Other keys in the same Row and Column as the T key are working. (Although 5 which is not working is on the same Column as T. But GB are on the same Column and do work properly). 3. I opened the switch to inspect for faulty switch. The inside of the switch is fairly simple, 2 metal... leafs? Contact each other to create a circuit when the key is pressed. Visibly, there are no issues. 4. I tried bridging from inside the switch using an external wire, DOESN'T WORK. But bridging the switch from below DOES WORK. Some photos of the build if necessary: Spoiler! https://imgur.com/a/3uM1ntl Apologies, attachments here kept failing... so IMGUR it is :S The photo shows how the board is wired from below, with the T switch highlighted. Again, bridging the ROW and COLUMNS for the T switch works and simulates the key press. But pressing the actual switch does not. ----- I'm hoping all of this made some sense xD... apologies for the long post. My question now is, if the switch is not faulty, and I CAN make the T key register by bridging along the Row / Column wires, why is it not working when I press the switch? Is my soldering job affecting it? As far as I know (in my super limited electronics knowledge), a circuit IS MADE when I press the switch. And if it works by bridging it from below, why wouldn't it work when I press the switch??? I mean, it can't get any simpler than that right? Metal touch metal = circuit = does it's job... Would re-soldering the switch (Switch, Diode, Row // Switch, Column) help? Why would it help? If it is already completing a circuit now, what difference would it make? Is there something I am not understanding? My solder joints look ... decent? In my opinion. I can't think of a reason why a 'bad looking' solder joint wouldn't work either. Since it's still completing a circuit regardless no??? Or am I totally wrong? Any help would be appreciated! Thank you so much in advance! EDIT: Ok, so I did a bit more trouble shooting, and have narrowed down the issue a bit more. When I bridge the faulty switch (T) at the switch pin BEFORE the diode, and then somewhere on the column wire, it does not work. Keys that are not faulty can be bridged BEFORE the diode and anywhere along their columns. This means something is wrong with my Switch Pin --> Diode. I will have to try resoldering that joint later tonight. My question now is, what would be the logical cause for this? Can a bad solder joint actually make this not work at all? (Prevent closing a circuit?) I don't think the solder joint looks bad at all, it looks like any other joint I've done. But I'll redo it regardless. EDIT2: Ok... apologies to anyone who spent time reading my post... I re-soldered (heated up, moved the pre-existing solder around a bit, applied a tiny bit of new additional solder) to my T switch, and now it works.... o___O so, conclusion is, something was indeed wrong with my solder joint, even though visually it looked fine, and a closed circuit SHOULD have been achieved regardless.... I'm still confused, and none of this makes sense to me personally. But I am glad it works now! Thanks again! __________________ <:D Last edited by PuYang; 09-09-2021 at 03:44 PM.