Designing a PWM to Analog mini board for fans
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@fcwilt said in Designing a PWM to Analog mini board for fans:
That's a skill I have never tried. I have a hot air soldering station but the project I purchased it for got canceled.
You can try one of those practice kits instead. https://www.aliexpress.com/item/32909277203.html
A solder iron, flux paste, and solder are all you need. A cheap Chinese stereoscopic optical microscope makes even easier.
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@zapta said in Designing a PWM to Analog mini board for fans:
You can try one of those practice kits instead. https://www.aliexpress.com/item/32909277203.html
Great idea.
A solder iron, flux paste, and solder are all you need. A cheap Chinese stereoscopic optical microscope makes even easier.
I actually have all of those.
Frederick
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@Egon-Net, one option you have is ordering assembled from vendors such as JLCPCB.
https://jlcpcb.com/smt-assembly
You may need to make design changes to reduce cost and use their standard parts. https://jlcpcb.com/parts
https://www.youtube.com/results?search_query=jlcpcb+assembly
Just an idea.
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@zapta said in Designing a PWM to Analog mini board for fans:
@Egon-Net, one option you have is ordering assembled from vendors such as JLCPCB.
https://jlcpcb.com/smt-assembly
You may need to make design changes to reduce cost and use their standard parts. https://jlcpcb.com/parts
https://www.youtube.com/results?search_query=jlcpcb+assembly
Just an idea.
I don't think we are going to do so many boards to be an advantage. For the time being I will do the boards by myself, but maybe in the future I'm overwhelmed by all the people wanting the boards and I have to look something like that!
BTW, I'm already a costumer of JLCPCB
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PCB assembly is easier if all the SMD components are on the same side. Then it's easily done using a hotplate, solder paste, and a Mylar solder stencil (available in the UK from Hobbytronics).
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@dc42 said in Designing a PWM to Analog mini board for fans:
PCB assembly is easier if all the SMD components are on the same side. Then it's easily done using a hotplate, solder paste, and a Mylar solder stencil (available in the UK from Hobbytronics).
I know, but for low quantity runs I do it with hot air and without stencil, with very good results. And for this design, size is a constrain. If I were to do a bigger run, I'd rearrange the pcb to be one side only and get it done somewhere lije JLCPCB.
Thanks for the advice anyway
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It’s getting really nice
I’m pumped to get my hands on one! -
Please everyone wanting some pcb's PM me with:
- Number of PCB's required
- Bare PCB/DIY kit/assembled
- Where to send in the world
I want to do a small batch first (10 or so), but since I don't know how many boards you all may need, maybe a bit bigger batch could be enough. Once I have this numbers, I'll put a price for every option.
Thanks in advance to everyone!
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Just received one query... No one else wants to enter the first batch?
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@Egon-Net said in Designing a PWM to Analog mini board for fans:
Just received one query... No one else wants to enter the first batch?
You asked for a PM but I don't know what that is.
I do want some as I previously mentioned.
If the price is right I would want 25.
Frederick
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@fcwilt said in Designing a PWM to Analog mini board for fans:
You asked for a PM but I don't know what that is.
PM = personal message, so just chat
/Julien
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First batch ordered!
15 PCB are on its way
If there is no problem with the design, I'll order about 50 more, wich would be enough for all the boards everyone asked for.
Anyone wants to betatest a board from this first batch once arrives?
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@Egon-Net said in Designing a PWM to Analog mini board for fans:
Anyone wants to betatest a board from this first batch once arrives?
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@Egon-Net said in Designing a PWM to Analog mini board for fans:
Anyone wants to betatest a board from this first batch once arrives?
Be happy to.
Frederick
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@Egon-Net I’m in for beta testing if you need. We are also pretty close geographically
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Boards arrived!
They are VERY small and very cute
As soon as I get some spare time I will assemble the first one and perform some testing. If it all works ok, then I will move it to the betatesters phase -
@Egon-Net, looks very nice, with good clearance for the mounting posts.
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Ok, here it is! First board mounted!
I have to recognize the accuracy of TINA TI simulation. It warned me about an inestability, but I wasn't sure if it was a simulation error or the real thing. Turned out it was the real thing, TINA TI even nailed the shape of the inestability checked with a real oscilloscope on the real circuit. Luckily, I already found that a capacitor fixed the inestability in TINA TI, and it worked too in real life:
It's a shame that such a cute board needs something that cluncky , but hey, that's what betatesting is for.
The good news is the circuit works very well, the output is very smooth, and roge fans work perfectly. PWM selector also works as expected, allowing active high/active low/open collector PWM. And although the opamp is supposed to work from 4.5V, I tested it as low as 3.3V and it still worked ok! And the output beautifully tracks Vin on the fly.
The response from PWM changing is as fast as "I can't measure it visually" (about 0.3 sec according to the simulation) .
So from now on, time to request betatest units, knowing they will need that extra capacitor. I have components to build 10 boards, and 14 bare pcb's.
Regarding cost, this is what I thought:
Just a bare board: 4€/piece
DIY kit (without headers/jumpers): 8€/kit
Fully assembled and tested (with optional headers/jumpers): 15€/piece
( + shipping costs).@ZipZap , @marcelorider , @fcwilt still interested in betatesting?
Once betatesting is completed, I'll modify the board with only SMD diode and a new smaller SMD capacitor, so the board will be a little bigger but cute again.
Comments?
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Some oscilloscope captures, all at 250Hz, 4V PWM, 12V Vin.
(Apologies for my function generator, is quite rubbish)99% PWM (oscilloscope can't detect duty cicle reliably)
75% PWM
50% PWM
25% PWM
1%PWM
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Sounds all swell to me.
I'm still in on beta-testing, i would like an assembled board (because of a missing hotair-gun...).
For the final version, i would like eight (8) non-assembled kits.
