New project - MSFS C++ USB interface

[Ioannis]

I think you are OK since the min pad to pad is 0.127mm and the PIC selected is 0.2mm

See here: https://jlcpcb.com/capabilities/pcb-capabilities

Ioannis

[Demon]

I think you are OK since the min pad to pad is 0.127mm and the PIC selected is 0.2mm

Ioannis

Except I have to be able to solder the prototypes.

I edited the BOM an PKP files as they instruct to get a better cost estimate for 5 10x10 panels. Over 50% is shipping.

Have you used their assembly service? I don't see any billing for the actual parts being assembled (Components is blank).

I have 2 capacitors, 2 resistors, in 1206 SMD format. I didn't see any way of telling them the specs of the components except for the value (my caps are ceramic, resistors are thick film - no mention of voltage, watts, tolerance, etc).

[Demon]

Ioannis (or anyone else who knows),

Have you noticed if they care how many holes are in a PCB?

[Demon]

This is what you get when you ask for specs from a company on the other side of the world.

[Ioannis]

I have used the assembly twice.

First time was on a small PCB with 5 or 6 components for 5 pieces. The PCB had a through hole connector that seemed hand soldered. Anyway it was OK all of them and worked fine.

The second attempt was more complicated PCB with a square PIC and more components (SMD and Through hole). I did a mistake on the selection of LED's. I chose the ones that light from the side and their engineers spotted the mistake, sent me email to explain the problem and the solution, and after I accepted it, I received the 20 pcs that were almost all working fine. One had a cold solder and was easy to fix.

Right now I am preparing my third order and I see that prices of PIC dropped enough, comparing 5-6 months ago.

My problem is that they have tons of passive components to choose from many (unknown) suppliers!

I had similar replies as you Robert about specs or other questions... Yes, communication might be difficult at times. Or most of the times!

About holes, no. I did not had to count them. There seems no limit or charge on this.

Ioannis

[Demon]

... One had a cold solder and was easy to fix.
...
My problem is that they have tons of passive components to choose from many (unknown) suppliers!

I had similar replies as you Robert about specs or other questions... Yes, communication might be difficult at times. Or most of the times!
...
Ioannis

Ok, so I can't just blindly trust them and slap these into a unit. I have to double-check each piece, cause if there's a problem, I'm the one that's gonna get yelled at.

Yeah, I suppose I'm gonna have to do a trial run of each circuit at first and measure the devices, then run a battery of destructive tests to see how far I can take them before PUFF the Magic Dragon shows up. Thing is, I doubt we can trust them to always provide the same material unless it's specified and documented somehow. Like capacitors, we could get a batch of 20-25V on the 1st run, then get 10V later on. You can't ask for a remake if it's not documented on the order.

What if we include it in the BOM, with a message to confirm with us? I mean, it's pretty easy for us to test the voltage and watt limit on capacitors and resistors.

- maybe extra columns at the end?

Volts, Tolerance for capacitors.
Watts, Tolerance for resistors.

So far, all my communications with Asia has been positive. They use a translator similar to google. When in doubt, always ask for confirmation.

I had a conversation just this summer with one lady. They're ordinary people just like us; except they're stuck in a dictatorship.

Robert

[Demon]

Ioannis, check this out.

Couple switches, buttons, resistors and LEDs, along with a truckload of holes:




The exact same circuit without the holes:




I guess they've moved away from milling the boards with endmills, but have moved on to waterjet (this is my first guess) or laser.

This is great news for me 'cause I'm going to need a lot of holes.

[Demon]

I think you are OK since the min pad to pad is 0.127mm and the PIC selected is 0.2mm

See here: https://jlcpcb.com/capabilities/pcb-capabilities

Ioannis

I've been playing with their online quote, and I noticed some irregularities when you get a quote on way, then backtrack and do it another (like with and without assembly, or when you change from single boards to panels). It seemed as though they forget to reset some variable and I got different prices.

So I got in the habit of always starting from step 1, and submitting the starting ZIP file. That way I had more predictable results.

Overall though, it is EXTREMELY economical to print with them. My small board costs me $100 CAD for 500 with shipping including assembly of 2 SMD resistors and 1 SMD capacitors. That's $0.20 each; making my own PCB boards is not even close to worth it.

I'm going to solder the switches/buttons/rotary switches/rotary encoders as well as the JST XH connectors to start. I'll see about the PIC MCUs main board later; gotta start somewhere.

[Ioannis]

I noticed that also. Some settings are revert to default so, yeah. Prices are not same.

Regarding assembly, for passivess like resistors and capacitors, you have so many to choose and the possibility to select one that is out of stock is too high! Also most of the brands are unknown to me with so many parameters to check. But the prices are in either case low.

On the other hand for MCUs, things are not so nice about prices or stock.

For 10 or 20pcs I did not bother and paid the extra money to have a PIC16F assembled.

Ioannis

[Demon]

I noticed that also. ...

For 10 or 20pcs I did not bother and paid the extra money to have a PIC16F assembled.

Ioannis

Good, I was hoping I wasn't seeing things the other night.

Yeah, that liquid solder paste and an air gun is changing the game. It's a lot less complicated for shaky hands like me to solder tiny MCU legs.

[Demon]

You really have to go through the entire estimate process to get the actual shipping fee, as well as customs and taxes. In the sample I tried, it went from $0.15 each to $0.30ish each.

I'm using clean ($2.10) and de-panel ($4.19) as well, that way boards should be relatively ready to use when they arrive. These fees were the same whether I did 3x3 or 10x10 panels (I didn't change the quantity, these were for 5 panels, I assume it'll increase for more panels).

It's kinda cool how they maintain an update of the entire production process. I made a small order of 5 units of single boards, just to learn how things work from A to Z. My real order will most likely be for 5 of 10x10.

[Ioannis]

Yes, it is very impressive the workflow!

Ioannis

[Demon]

It would figure that the very next day that I send my order, I find an even better way to debounce pushbutton switches using 74HC14 ICs. I hadn't seen this one before. I had only seen the RC design. Oh well, live and learn.

https://hackaday.com/2015/12/09/embe...uttons-part-i/


About not knowing which brand or specs of components used by JLCPCB; I scan their database for components IN STOCK using search parameters like RESISTOR 1206 10K 250MW then sort their output on descending price.

https://jlcpcb.com/parts/all-electronic-components


I looked for a known brand and picked their component with the lowest tolerance percentage; I used Yageo for this project (mainly cause it's the only one that I recognized).