BluepillF4 PCBs

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victor_pv
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BluepillF4 PCBs

Post by victor_pv » Sat Feb 03, 2018 5:55 pm

**UPDATED**

Seems like Squonk has the final design in the F4 board, and perhaps we can order the PCBs soon.
As mentioned in the AllPCBs thread, thanks to all the people that signed up with the link, I can order PCBs with the bonus.
Just found out while ordering that the bonus can't be used to pay for an order, but just to obtain a 10% discount, so the boards were not free.
Anyway I am ordering a bunch of 40 for the US, way more than I would assemble ever, so the offer stands to ship some to people willing to assemble some.


I live in the US, and have a diy reflow oven that has worked fine for me so far. I am not set for volume production though.
I can ship a bunch of bare PCBs to anyone in the US for the cost of shipping, that should be under $1 (I believe we don't need bubble envelopes for bare PCBs).

I can reflow a few with the passive components, and you are left to solder voltage regulators and MCU, since they are larger they are normally easy to solder with an iron if you have a bit of experience, but that will depend how many people ask for it, since like I said I'm doing it manually so it takes a good amount of time.

These are still prototype PCBs, so we may find flaws, you may find traces that you need to cut and run a piece of wire, you may even have to trash a board altogether if there is a short that kills your MCU, so ask for PCBs if you understand this is not to get a final commercial product, but rather to contribute with your time to check and test them, and each board will cost you a few $ in components and a few hours of your time. There are a lot of small 0603 components.

If you want to assemble a few and test them, please post here how many PCBs you think you will want.
If you can't deal with the 0603 components but think you can take care of the MCU, regulators, usb port if I reflow the 0603 components, say so, and I'll see how many I can reflow.

Bare boards will go first, and only I have enough time and after I assemble some for myself, may be able to reflow a few for other people.

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RogerClark
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Re: BluepillF4 PCBs

Post by RogerClark » Sat Feb 03, 2018 9:03 pm

I would just buy the minimum order of PCBs

IMHO with such a compact board,there is a high lightlyhood of there being a small but critical error, or perhaps a tolerance which is too tight for the cheap manufacturing plant

I worked in the electronics industry quite a few years ago, and virtually every board that was designed had at least one problem.
Sometimes this was minor and we could compensate in the firmware etc, but often we had to slightly modify the PCB at least once.

I know in this case , we have many very talented people looking at the PCB, but as it’s Sooooo compact and uses a processor we don’t use that often, I still think there is a chance the boards won’t fully function correctly.

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Squonk42
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Re: BluepillF4 PCBs

Post by Squonk42 » Sat Feb 03, 2018 9:07 pm

Of course, I agree with you Roger, same experience!

victor_pv
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Re: BluepillF4 PCBs

Post by victor_pv » Sat Feb 03, 2018 10:32 pm

The thing is, 5 boards cost $13. 55 boards cost $20.
If it works or it doesn't cost about the same. If I order 55 at once, and it does work, then there is 50 more to send around.

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mrburnette
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Re: BluepillF4 PCBs

Post by mrburnette » Sun Feb 04, 2018 4:33 am

victor_pv wrote:
Sat Feb 03, 2018 10:32 pm
The thing is, 5 boards cost $13. 55 boards cost $20.
If it works or it doesn't cost about the same. If I order 55 at once, and it does work, then there is 50 more to send around.
I know there was a good deal of interest originally and I was even interested in assembling one. But that like 90 days ago. Today, I am distracted with other interests and if I were to procure a board, it would likely never get assembled. Time changes everything.

I think the design effort for the board is fantastic and I think a completely assembled board would be highly desirable if in the $5 range, but with the ESP32 pricing now under $5 and the rPi_Zero-W at $5 (sale) here in Atlanta, I just do not see myself taking the time to 1) source and order the uC and 2) assemble the board.


I have really enjoyed reading the ongoing discussion and decisions made in the long main thread; enlightening stuff.


Ray

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Squonk42
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Re: BluepillF4 PCBs

Post by Squonk42 » Sun Feb 04, 2018 10:43 am

You can add the Onion Omega 2 to the list of cheap boards.

But regarding all other competitive boards, the situation has not changed much in 90 days: maybe the ESP32 is now a little bit cheaper, but it was already in the <$7 game then. I know this one and the smaller ESP8266 very well (I helped to support the Xtensa CPU in GCC), but the cons are the number of GPIOs and high power consumption. Great board though, I am also using it a lot!

As for the RPi0W, the situation is not that simple: if you can get some at MicroCenter for $5 (lucky you!), for most of us here in Europe, it is difficult to get one below $20 with shipping :cry:

I agree the STM32F4 only fills the needs for a niche market between these boards and the cheaper Arduino mini/micro and BluePill boards in the <$2 range.

But with a 168 MHz / 210 DMIPS Cortex M4 with single precision FPU, DSP instructions and its plethora of peripherals, the STM32F4 addresses applications requiring high-processing power and real-time control, such as flight controllers in drone applications, where they dominate all other MCU types by far.

Of course, assembling a board from scratch takes time, but it is fun and rewarding, and it is up to everybody to see an interest in it!

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Pito
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Re: BluepillF4 PCBs

Post by Pito » Sun Feb 04, 2018 11:16 am

Assembling such a board is fun for us who work with 0603/bga/qfn and are equipped with tools and with skills :)
99% of people who want to pay and play are unhappy when ie. even the pin-header is not soldered in already..
This board to assemble at home would require some experience, however.
Thus for US market you have to offer a fully assembled board for $5, as the Arduino Company and Raspberry Pi Foundation do :P
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Squonk42
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Re: BluepillF4 PCBs

Post by Squonk42 » Sun Feb 04, 2018 1:16 pm

Yes, most users will want assembled boards. This version is still a prototype to be tested even for its most basic functions (e.g. turn on power), so this is different. We will be able to deliver some PCBs to volunteers, but expect tears, sweat and blood. No guarantee whatsoever that it will work for application X, Y or Z.

Then once we have a working prototype, we can make plans to have them manufactured and shipped pre-assembled (W/ or W/O pin headers soldered) directly from China, as this is the only effective distribution channel: for Rpi0W, the main online distributors are charging a lot for shipping, and small online shops tend to bundle this with junk to get a minimum amount order of at least $10, then you get additional $5 shipping fees.

But the first step is debugging the initial prototype board!

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mrburnette
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Re: BluepillF4 PCBs

Post by mrburnette » Sun Feb 04, 2018 1:53 pm

Oh, my, my regrets for causing this thread to go off topic ... I seem to be a lightning rod for such things.
But with a 168 MHz / 210 DMIPS Cortex M4 with single precision FPU, DSP instructions and its plethora of peripherals, the STM32F4 addresses applications requiring high-processing power and real-time control, such as flight controllers in drone applications, where they dominate all other MCU types by far.
Those that follow my rants know that I am a big proponent of using high performance, low cost microcontroller boards in conjunction with RTOS higher level products for providing near-real-time data aggregation.

My intent on posting was to clarify why I wanted a board to assemble back at the start of Autumn '17 and now mid-way into 1Q18, I am no longer interested. My decision certainly should not reflect in any manner on the usefulness of the design. Many members seemed interested in having an initial board and in doing the evaluation, I am just removing my name from that desire so someone else can participate.

Ray

victor_pv
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Re: BluepillF4 PCBs

Post by victor_pv » Sun Feb 04, 2018 2:05 pm

Ray, and I think you make a good point, things move fast.
I decided to open this post because another forum member sent me a PM saying he would be happy to get some PCB and try to assemble to join in the effort of developing the prototype.
As long as people understand this is a prototype and the effort required, I think there is value letting more people test it, so we may move along faster, so I decided to open the thread to let people willing to join the effort know I can ship some bare PCBs to them, and if I have the time, I may be able to solder the SMD components in a few boards. While I can only work in a board at a time, if 5 other people is testing them at the same time I am sure we will move faster in finding any correction needed, or if there is no flaws in testing GPIO, peripherals, clocks, RTC, etc etc.
We are not yet at the stage of mass producing them, but perhaps we can get to that point soon. :D

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