Shorty short finder branched and released as ShortyPen!

[clearchris]

News from eevblog:

https://gitlab.com/jdobry/shortypen/

https://www.eevblog.com/forum/testge...85/#msg4618285

ShortyPen.jpg

[stj]

time to see how much has changed.
(how much of the parts i got are now useless)
i already see the mcu is from ST in the pictures!

[clearchris]

The stm32 mcu is a great upgrade. As much as I have liked the arduinos, their time has long since passed. For a similar price to an arduino clone, you can get an stm32, an esp32 with wifi, or an rp2040, all of which are massive upgrades over the arduino.

[stj]

rp2040 has no cache and no tolerence for 5v on the inputs,
esp has hardly any pins.

i do have several stm32 Blue-Pill's handy though

[itstallion]

Hi,

I'm going to build a couple of these shorty pens and I've compiled a list of components available at Digi-Key. This should save someone else some time. Feel free to correct any incorrect components. They have everything except for U2 and U3. I'm getting those from Mouser as soon as they are back in stock. I'll keep updating this thread as needed.

Thanks
mark

BOM_shortyPen.csv.txt

[stj]

you should sell spare pcb's to u.s. customers.
the chinese pcb places will make you 5 or 10 pcb's for a couple of $ and kill you on the postage.
by selling spare boards you can recover your losses to the fucks at UPS/FEDEX etc.

[clearchris]

These boards are super small, wouldn't they fall under small-packet postage? It's not quick, but it's pretty cheap. But yeah, cheaper in quantity for sure.

itstallion: Have you had success soldering stm32 chips? If you have, do you have any tricks? I have not been successful.

[itstallion]

I'm going to be assembling this thing under a microscope so hopefully it won't be an issue. Hopefully. I may be a masochist as I didn't order the stencil. I've got some experience with Motorola and Arduino. This will be my first time with the stm32. I want to build a reflow oven one day. Anyone have any experience with one of those. Is it worth building one.

[clearchris]

Originally Posted by itstallion

I'm going to be assembling this thing under a microscope so hopefully it won't be an issue. Hopefully. I may be a masochist as I didn't order the stencil. I've got some experience with Motorola and Arduino. This will be my first time with the stm32. I want to build a reflow oven one day. Anyone have any experience with one of those. Is it worth building one.

It's not the accuracy that was the issue, I think the issue is overheating / destroying the chip. The chips absorb moisture, and that moisture tends to expand and destroy the chip during heating.

I haven't tried reflowing an stm32 in the reflow oven, but I do have a few chips in my dessicant pail. And yes, love my reflow oven, but I rarely do reflow in it.

I have a thread on here about my oven, I also put a lot up on hackaday.
https://hackaday.io/project/171619-n...-a-reflow-oven

The biggest trade off I think is that if you really want to do reflow, you want a small an oven as you can manage, and quartz heaters are definitely better. My oven (found on curb) has resistive heaters, but I added halogen lamps, which is mostly what I use. A built in fan is pretty much a must, as is getting the pans that come with the oven (unless you want to make one out of sheet metal). The bigger the oven, the harder it is to heat to hit those trapezoidal reflow curves, but the more versatile it is because you can put other things in it too.

Were I to do it over again, I'd probably gut the resistive heaters, they are just so slow heating, and use 4 halogens instead of the 4 resitive heaters and 2 halogens. I'd also strongly consider buying a meter or two of silicone foam for insulation instead of the ceramic. Doing the hybrid relay / SSR setup was a total win, having the heater individually selectable has been great, 90% of the time, I run the single bottom halogen only. Ramp speed is quite reasonable, and easy to shield sentitive items (filament spools, desiccant, mobile phones, etc) from direct heat. I wish I knew how to speed control the AC fan though. It's currently full blast or off.

Using klipper (3d printer firmware) was an amazing success. It works so well, whenever I want the oven to do something new, I just write a new gcode script and upload it to the oven. It works so well, I haven't touched the software after the initial install, it's still running probably 3 year old code at this point.

[diif]

I'd put the PCB on a hot plate, then flip it over to hand solder the display and buttons.

[itstallion]

I think I'll run all the components through a pre heat before soldering them. That should help with the moisture issues.

I have some experience with Klipper. Interesting use of Klipper.

[clearchris]

Originally Posted by itstallion

I think I'll run all the components through a pre heat before soldering them. That should help with the moisture issues.

I have some experience with Klipper. Interesting use of Klipper.

If you purchase the stm32 chips from a reputable place, it will come with a moisture indicating paper, and it will tell you if you need to pre-heat (if you follow their processes exactly). I'd probably do it anyway.

Yeah, the oven was state of the art a few years ago, but since then, I have heard from others who have made their own KlipperOvens. Yeah, detractors will say that it's a lot of hardware for an oven, you could get by with only an MCU, but IMHO, it's worth it for the feature set, and for how very little I had to code. At that point I had been using klipper for years, I didn't even have to figure out klipper.

[stj]

you wont find st chips easily,
even the chinese have had to adapt a lot of designs to use licensed clones


btw, has anybody tried make a small reflow oven out of a so-called "air fryer" ??
it seems to me that if you have air moving around the heating would be more even.

[sam_sam_sam]

Originally Posted by stj

btw, has anybody tried make a small reflow oven out of a so-called "air fryer" ??
it seems to me that if you have air moving around the heating would be more even.

Now this is an interesting idea I need to try this when my convection oven takes a shit to experiment with this idea

The only thing that I might have to do is use a more accurate temperature controller for best results

Because the cheaper models use a mechanical thermostat switch to control the temperature

The more expensive ones use some type of temperature control that seems to be more accurate controlling the temperature because I have both versions of the convection ovens and you do get different results depending on what food you using it for

[stj]

i assumed you had ripped out the control and fitted a pwm drive anyway.
most diy ovens are arduino controlled

[clearchris]

My convection toaster oven does have a fan in it, the temperature is very stable, can easily hold 1c, and I bet part of that is electrical noise on my ancient max type-k reader chip. I wouldn't bother if the toaster oven doesn't have a fan.

From the way I understand air fryers, they move a lot of air out, so I don't know that they could reach the target temperatures quickly enough. However, I haven't really looked into it. If they are all quartz heaters or other heater with fast response it might be possible.

I thought stm32 chips were available again? Is there still a shortage? Maybe I have some to trade