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A project log for Soldering pen

Cheaper fine-pitch soldering setup with Wellers RT tips

hp-banjohatHP (@banjohat) 04/26/2016 at 12:394 Comments

One of the fundamental ideas with the soldering pen was to have a small package and a 3d printed casing for the whole project. I don't know how it happened but somehow I completely missed the fact that the jack connector was not in the same plane as the board. of course. therefore I decided to look for a very low profile connector instead.

The first and second revision of the PCB showed that the principle was working. I could (easily) make a soldering pen with a small footprint and a nice set of features. Now I could focus more on the mechanics of the project.

I've found the connector: CUI SJ-3502-SMT. It's only rated for 1A but so is most of the jack connectors I can find. My biggest problem: slotted holes!

It turns out that DesignSpark PCB can't do slotted holes! Argh! Somehow I've always managed to get around this until now, but this was very much needed. What should I do? A new CAD tool is not a very funny solution.

Anyway I decided to have a look and I found CircuitMaker - the 'free' version of Altium, that in return requires that you store your project publicly. Fair enough I'm all for open source anyway and having a platform to share from is not that bad. At least I knew that I could get my slottet holes.

Fast forward 2 days and I've found out that Circuitmaker gets compoent specifications and footprints directly from octopart. this is insanely nice - crazy nice! beacuse that means that when I'm done with a component it will be shared for everybody else to use. voilá, a single global component library. wow!

Also Circuitmaker, being Altium under the hood, of course works in 3D. So almost all components have 3d models attached.

Look at this:

Isn't that beautiful?

The new low-profil jack connector is clearly visible and I've changed the LED to a SMD version.

I'm really close to removing the programming header and replacing it with.... something smaller. I have an idea for something that could fit in that space..

Discussions

René Arts wrote 04/28/2016 at 13:13 point

Great log again! Have you considered using WS2812 SMD (Neopixel)/SK6812 led's? It could possibly free up some IO pins and even be possible to chain a few LEDs. 

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HP (@banjohat) wrote 04/28/2016 at 13:25 point

Thanks!

Yeah I've considered the idea. But I dismissed the thought again because I want to have the firmware as basic as possible. Also I'm not sure if the WS2812 will work without an external oscillator? 

Also the WS2812 would be larger than I really want it to be...

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René Arts wrote 04/28/2016 at 18:02 point

Good point of the oscillator. However the WS2812 is quite robust in the timing it accepts, I don't know exactly how robust. I'd think the 35/35mm version wouldn't be too large? Though indeed keeping it simple does the job as well. This soldering pen should solder after all... being fancy is not its main task. 

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HP (@banjohat) wrote 04/28/2016 at 19:12 point

Exactly ;)
Well, I'm thinking of putting an accelerometer on it - imagine a situation where the pen is powered by a battery in your pocket and you're soldering up under the roof (yes I'm doing things like that!) at that point it would be really nice to be able to just make a toubletap on the pen and make it turn on or off. Of course it should still have the hall sensor for normal operation. At this point it's only an idea but I really like it.

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