DIY : tsnm (Touch Sensing Note Memory) by Doboz

[soggybag]

I’m just starting to build this. I notice IC 1 and 2 do not have a dot or a notch. From the picture above and general experience,

I’m guessing that pin 1 is in the lower left if you’re reading the part number horizontally left to right? can someone confirm this for me before I start soldering.

[mutedial]

slope side of the IC on the left, top (left) pin is pin 1 (i.e. your placement looks correct to me)

[soggybag]

Thanks for the reply. The two sides don’t really show much of a slope or I can’t see it.

[mutedial]

they are small — i usually use a loupe etc — but if you hold it up flat you’ll see one long side is angled and the other side is not.

[soggybag]

Thanks for pointing that out. I was looking for the bevel on the left or right. Now I see it along the bottom.

[infovore]

A note on orientation - in general, we describe the pins as being on the ‘left’ or ‘right’ - the slope is on the ‘left’ side, with pin 1 at the top left. Don’t ever rely on silkscreening - print - on the top of a chip to confirm which way up it is. the only thing you can rely on is that slanted edge. (Or, in the case of DIL parts, the notch or dot).

[soggybag]

Slowly making progress. These 0603 resistors are really small! My biggest worry is I’ll drop one and not be able to find it. Soldering is not that hard. It’s more work just maneuvering the piece into place and holding it steady while applying the iron. You really need a magnifying glass!

[grey]

Yeah, 0603 is easier with some magnification. There’s a decent amount of space between components though, so it’s not too bad.

Sticky solder flux is very helpful.

[soggybag]

The act of soldering the parts is not so hard. Dealing with getting a tiny part, the size of a crumb, out of the package and into position is a little nerve wracking.

There is a lot of room on the pcb which helps. Everything could have been done on the same size board with through hole components.

I don’t know if this bugs anyone else but, I’m a little annoyed at the amount of trash. I’ll throw away an anti static bag the size of a small sandwich, a cardboard business card, a packet of desiccant, a smaller plastic ziplock bag, and a tiny plastic tray all for a single transistor or IC much smaller than my pinky fingernail.

[kburwash]

Haha ya I have a box full of baggies, in case I ever become a drug dealer.

[grey]

I’m a little annoyed at the amount of trash.

Holy shit, this.

I have two projects that I’m waiting to start, and I have a pile of boxes 50x the 12hp of modules they’ll go towards. It’s by far my least favorite part of DIY, and there doesn’t seem to be a better way aside from buying in bulk if you’re building a whole run of modules, which most of us probably aren’t.

[bmoren]

it’s true that there is a lot of trash from supping parts there is only 2 obvious things to do:
buy more parts in bulk
save the bags / boxes and re-use them

If you’ve ever gotten a module from me in the FS/FT section, it’s likely been wrapped up in some anti static bag that was reused. I’ve also been repackaging parts for kits into the bags that are sitting in my studio. I even used the bags recently to sort and store some SD cards. I suppose it’d not a perfect solution, but It’s better than trashing it all.

[soggybag]

The SMD stuff is new to me. I’m getting the hang of it. I’m using a soldering iron. I really need a smaller tip. The one I have works, but tip seems a little too blunt for this kind of work.

Flux is important. I have been using liquid flux. I also bought some paste which I might test.

You really need very little solder on the tip. Just a tiny bit, if you can see solder on the tip it’s pro too much. Like vermouth and gin.

Some fine tweezers are essential for getting parts on to the board. I use a dental tool to hold the part in place then touch the pad with the iron. I have a magnifier lamp that helps see what’s going on.

I don’t fully trust my work yet. The parts are so small it’s hard to inspect the joints. I tes each resistor with the multimeter at traces connected to it after each is soldered.

[zuliani]

Urg yes, all the time! Almost always with the same plate, which I now just avoid. Poor plate!

[soggybag]

When testing I look for tw points on either side of the part. I can usually find another point by following the track. If one end of the part connects to the ground plane you can test that side from any ground connection.

This works for resistors and diodes. It probably won’t work for capacitors. My meter doesn’t caps through the probes. I might be able to rig something up. Though, I’m gaining confidence in my ability to solder SMD so might skip testing the caps.

[grey]

I didn’t test anything, but I was very careful about part placement. Worked fine.

Again, can’t stress it enough:

Sticky solder flux is you best friend for those tiny components if you’re hand soldering. Holds everything in place for you. All you have to do is get it from the packaging to the board then nudge it into place.

On an unrealted note: My sticky notes have mostly cleared up? I don’t know if recalibration/settings made any difference or if I’ve just gotten better at not doing what makes notes stick, but my unit has been behaving for the past while.

[soggybag]

What am I missing here? I’m guessing these get soldered to the pads on the touch board. The alteration is off on the bottom set of pins!

Do I need to cut one off and solder it to the end? Or maybe a set of three might make this easier?

[soggybag]

Seems like it might be good to solder the jacks and rotary encoder first? Trying to align with the LED matrix?

[bmoren]

I’d do a set of 3, but they should line up with the pads.

[soggybag]

I can put them in a socket before soldering.

1. Jacks and rotary encoder need to placed on the board, no solder.

2)Then the touch board positioned. Next solder the jacks and encoder, maybe visually align the LED holes with the holes in the touch board as much as possible.

3. Next, take it apart, and solder the header that connects the board with the PCB.

4. put the right angle pins in the header and mount the PCB and hope everything aligns with the pads.