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Messages - gelbanana
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Project logs / Re: USB voltage current monitor
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Project logs / Re: USB voltage current monitor
If shipped via HK would take even longer.
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Project logs / Re: USB voltage current monitor
Yup I used seeedstudio.
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Project logs / Re: USB voltage current monitor
Apparently, the amp meter does not like to be powered by the same source that its measuring.
So, I whacked together a veroboard with 2 CR2025 in series and a jumper as a power switch.
I've ended up with the board now twice its thickness. Well on the bright side its not drawing power from the USB host.
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Project logs / Re: USB voltage current monitor
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Project logs / Re: USB voltage current monitor
Not really,
Passive components are all 0805, the ferrite I've used are from the DP parts list.
Pin headers are 0.1" pitch
USB connectors are standard size.
The component values are listed on the schemetic or you can get the eagle files and generate the BOM list
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Project logs / Re: USB voltage current monitor
@ MickM I tried cutting slots for the usb ports but the tin starts warping and became flimsy. Its always fun to see peoples reaction when im using it in public transport
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Project logs / Re: USB voltage current monitor
That would mean an increased cost of BOM.
I thought of using this for Rpi as a power injector for ext hdd. Doesnt need the additional powered hub
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Project logs / Re: USB voltage current monitor
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Project logs / Re: USB voltage current monitor
@Brett Sure will post the files here when I get back.
BTW: All five boards been taken, that sure was fast.
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Project logs / USB voltage current monitor
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Unlike the others out there that uses polyfuse as a short-circuit protection, mine uses TPS2051C which is a Current-Limited USB Power Distribution Switch.
I chose it because:
1) ULVO at 4.5v
2) Output enable pin
3) Fault output pin
Currently, I'm using it together with a multimeter but in future there will be another board stacked on top of it. Running a mcu and a oled/lcd display.
The fault pin will be attached to the mcu interrupt pin. When the IC triggers a fault, the mcu will disable the output. And reset it by pressing a button. Just like a circuit breaker.
BTW I have 5 extra pcb to give away. If you're interested let me know, I'll send you one. Or perhaps a DP free pcb give away?
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General discussion / Re: Repairing a Weller Soldering station
Just a matter of time before someone figures it out.
[quote author="Alex555"]Maybe we need lower resolution pics. Some people are way too hyper observant.[/quote]
Beg to differ, I actually prefer images where you can really read the printed words on the paper
[quote author="presslab"]I see you have a vacuum gauge on there. If you could, I'd like to know what the maximum vacuum reading is if you cap off the ports with your finger. Thanks![/quote]
It can do about 0.5 bar max
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General discussion / Re: Repairing a Weller Soldering station
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General discussion / Repairing a Weller Soldering station
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The problem is that readings are way off and all over the place and you can see that the 7segments are actually flickering.
http://www.youtube.com/watch?v=Zs80QPODk_o
My first approach was to look for visual signs of component failure and everything looks fine. So, next is to probe the temperature control board. Check out the old school pcb routing.
The board gets its power from the 12vac through 1/2 wave rectifier, filter cap, 7805 regulator and another filter cap.
Initially, the voltage measured at the regulator was 7v at the input and 4.2v at the output. The filter cap was quite warm.
Tested the cap ESR was 0.7ohms and not shorted. My capacitor meter was only limited to 200uF max. So I concluded that the cap has lost its capacitance over time.
Replaced them with what ever I have in my junk bin and it works like a charm. Did some quick calibration with a thermal probe.
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I've decided to replaced all the caps just in case. Im actually surprised that there are very few ICs in one of these.
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Phillips caps. When was the last time you heard of them? I know they were acquired by some company, Vishay was it?
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An overall shot of the internal. The transformer is rated at 24v 280va. Which took up most of the weight.
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I've also took the opportunity to strip the old paint with a wire brush. Some fine sanding and elbow grease and finally a couple of clear coat. Tried to create the brush alu effect. Unfortunately, the desolder tool wasn't working, it dint get hot but the pump works fine though. Looks like another job for another time.
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