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Are you buying the powersupply kit ?

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No
Perhaps

Author Topic: Do you want to buy the powersupply kit ?  (Read 45181 times)

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Offline plunger

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Re: Do you want to buy the powersupply kit ?
« Reply #75 on: January 12, 2012, 09:34:47 pm »
Alrighty, for my first power supply I'll get something in the 0-30v 0-5A range. But I'm not buying any cheap ebay stuff  :P
 

Offline McMonster

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Re: Do you want to buy the powersupply kit ?
« Reply #76 on: January 13, 2012, 12:22:29 pm »
You willl quickly find out that a good brand PSU can cost well over six times more than those cheap ones. ;)

I don't think it's really wrong to get a cheap one for start. Just make sure it has current limiting, not shutdown on excess current.
 

Offline rr100

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Re: Do you want to buy the powersupply kit ?
« Reply #77 on: January 13, 2012, 08:16:10 pm »
I designed it for a specific reason you have not really seen yet.
Hah, sorry but I might've just guessed what's that reason. So, I'm trying to reverse engineer some high capacity Li* batteries (with their own "black box" BMS); I'm using in the process two multimeters, two PSes, two rheostats and a bunch of car bulbs for load (who had the bright idea to put "intelligence" in a battery?!). Anyway I've figured out the algorithm that would eventually work. And I heard a "PIIING". Fortunately only in my head. There are two reasons for which a programmable precision PS would be nice to have:
1. except for just dropping the voltage with the load a PS might need to be smarter. You might want to control how the voltage is dropped with the load or even more you might want to control how the PS behaves IN TIME. Example of particular algorithm (which in fact I needed today and I simulate by hand): when the load goes to X Ampere  drop the voltage then raise it slowly until you reach a predifined value. We have smart loads, time for smart PSes
2. now while I wait for the thing to charge it would be nice to have the power integrated over time and count the energy that was put into the system. This is probably what Dave wants, especially with precision low current measurements and the previous blogs about charging stuff and portable devices, etc. Is this it? Is it? I promise I won't tell  8)
 

Offline all_repair

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Re: Do you want to buy the powersupply kit ?
« Reply #78 on: January 16, 2012, 04:27:30 am »
Rough use or charging need, I think Dave kits shall not be able to compete with the Chinese made supplies.  I had many of those, as well several HP PS.

If Dave power supply can be use as a voltage and current standard to check my multimeters, and as a bonus use for the calibration sources for the 4-20mA instruments as well as some voltage calibration, I would definitely get at least one.

But as a kits, I wonder how to adjust for the accuracy.
 

Offline EEVblog

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Re: Do you want to buy the powersupply kit ?
« Reply #79 on: January 16, 2012, 05:25:19 am »
2. now while I wait for the thing to charge it would be nice to have the power integrated over time and count the energy that was put into the system. This is probably what Dave wants, especially with precision low current measurements and the previous blogs about charging stuff and portable devices, etc. Is this it? Is it? I promise I won't tell  8)

Nope, try again.
It's not as complex as you think.
In fact, the main driver is so simple, some might even say it's a pointless or silly feature.

Dave.
 

Offline Armin_Balija

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Re: Do you want to buy the powersupply kit ?
« Reply #80 on: January 16, 2012, 06:27:18 am »
Didn't care about all the complaints people were going on about. I ordered all the parts in dave's video and plan to build it up myself. First starting with the original PSU and then going to see if the uSupply is too complicated for me.

Thanks Dave!
 

Offline shebu18

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Re: Do you want to buy the powersupply kit ?
« Reply #81 on: January 16, 2012, 07:15:07 am »
kind of silly question, when do i use de uCurrent, or why would i use it? You have there 3 conections, V+, V- and sense. Where does sense go? If you answered any of my questions in a blog video then tell mi which and i watch it again.


I also ordered all the components and now i will start to build it when they arrive.


Thanks.



 

Offline EEVblog

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Re: Do you want to buy the powersupply kit ?
« Reply #82 on: January 16, 2012, 08:12:57 am »
kind of silly question, when do i use de uCurrent, or why would i use it? You have there 3 conections, V+, V- and sense. Where does sense go? If you answered any of my questions in a blog video then tell mi which and i watch it again.

There is a whole PDF article on it:
http://www.eevblog.com/projects/ucurrent/

Dave.
 

Offline vk6hdx

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Re: Do you want to buy the powersupply kit ?
« Reply #83 on: January 16, 2012, 08:38:12 am »
There is a whole PDF article on it:
http://www.eevblog.com/projects/ucurrent/
Dave.
The Links on that page all go to http://alternatezone.com and seem to be broken at the moment.. is that site down?
 

Offline Chet T16

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Re: Do you want to buy the powersupply kit ?
« Reply #84 on: January 16, 2012, 08:39:03 am »

Nope, try again.
It's not as complex as you think.
In fact, the main driver is so simple, some might even say it's a pointless or silly feature.

Dave.

Boobs? Fingers crossed!
Chet
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Online IanB

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Re: Do you want to buy the powersupply kit ?
« Reply #85 on: January 16, 2012, 08:59:40 am »
The Links on that page all go to http://alternatezone.com and seem to be broken at the moment.. is that site down?

It was working for me earlier today, but it does seem to be dead right now. I would try again later, perhaps it is just temporarily offline.
I'm not an EE--what am I doing here?
 

Offline EEVblog

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Re: Do you want to buy the powersupply kit ?
« Reply #86 on: January 16, 2012, 10:25:20 am »
The Links on that page all go to http://alternatezone.com and seem to be broken at the moment.. is that site down?

It was working for me earlier today, but it does seem to be dead right now. I would try again later, perhaps it is just temporarily offline.

I now recall my provider sending an email about site outage for maintenance, so that must be it.

Dave.
 

Offline Blue

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Re: Do you want to buy the powersupply kit ?
« Reply #87 on: February 01, 2012, 04:31:32 pm »
The poll is still open for a few days.  :)
 

Offline MikeJuszkie

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Re: Do you want to buy the powersupply kit ?
« Reply #88 on: February 07, 2012, 05:45:13 pm »
I totally want one maybe even a second one to mod and keep the first one original. I am in the works of designing my own power supply that is digitally controlled via Arduino  but it will be driven differently and have separate specs. Once I saw this build I figured I would get my hands dirty in my spare time in between class work and do one of my own.
 

Offline kiyotewolf

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Re: Do you want to buy the powersupply kit ?
« Reply #89 on: February 08, 2012, 05:13:16 am »
For people worried about the cost of customs, why not sell the thing as all the custom circuit boards by themselves, some of the hard to find components included in the package, then order parts directly from Digikey or whoever, using a parts list?

Break it up into a smaller money figure, by shipping the custom boards, whatever stuff should be sent along that's important, or proprietary, then let the user get the rest of the parts, direct from a supplier?

<.< I don't know if that would be better or worse than just the entire kit, all at once.



~Paul
 

Offline electrode

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Re: Do you want to buy the powersupply kit ?
« Reply #90 on: February 08, 2012, 05:17:11 am »
Depends how much stuffing around Dave is willing to do. He could take on the Adafruit strategy, which is generally 3 options:
- Full kit
- PCB only
- Pre-programmed microcontroller

15 different options, or a checkbox for every single part for Dave to manually count out and package is not gonna happen...
 

Offline kiyotewolf

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Re: Do you want to buy the powersupply kit ?
« Reply #91 on: February 08, 2012, 05:23:57 am »
Having a choose your own adventure option is just idiotic, .. make it modest, option one being the PCB's and a few goodies, or the full on Delorean.



~Paul
 

Offline EEVblog

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Re: Do you want to buy the powersupply kit ?
« Reply #92 on: February 08, 2012, 05:58:42 am »
Depends how much stuffing around Dave is willing to do. He could take on the Adafruit strategy, which is generally 3 options:
- Full kit
- PCB only
- Pre-programmed microcontroller

15 different options, or a checkbox for every single part for Dave to manually count out and package is not gonna happen...

Yes, the less options in my shop to order, the less hassle it is.
The only reason Adafruit and similar online shops survive and do what they do is because they have a full time staff of dozens or more and almost fully automated ordering, labeling, and invoicing systems built up over many years.
I have the problem of not wanting to be a retail kit business/store, but I also enjoy providing the kits and bits for projects directly myself. So there ends up being this rather annoyingly large intermediate region of success between selling kits/products in the dozens/hundreds, and selling in the thousands, and the "surge" of orders when I announce something.

For instance, assembling, testing, packing, and shipping my batches of 50 uCurrents takes several full days of work.
The next batch of 200 will take proportionally longer again, probably the best part of a weeks full time work to shift those units. A lot of work, but just manageable without impacting the blog much.
Bigger numbers than that, or multiple items in a bigger online store and I'm in trouble.

And then there is the customs hassle, where it really isn't worth my while to ship a blank PCB worth $10 or $20 internationally because of the paperwork involved. I can't just pop it in an express satchel and send it. And likewise for multiple items in a shopping cart. It is much easier and more streamlined if everyone orders just the same thing (e.g. I print out labels in batches, wrap and pack things in batches etc). If everyone wants something different in their order then I have to process and pack orders one-by-one to ensure it's not goofed up.

I ditched the uCurrent kit because most people didn't want it, and it was a hassle to kit up the SMD parts. But I like the idea for the PSU.
It's likely I'll pay someone to kit up these PSU parts for me, as I can't see that being a good use of my time.

Of course you could argue that none of this a good use of my time and I should just offload the whole she-bang to Adafruit or Seedstudio and take a small commission. But then the personal joy of it is gone, and someone else gets the majority of the profit.
Likewise if I start hiring someone say part-time.

I guess it's just suck it and see!

Dave.
 

Online IanB

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Re: Do you want to buy the powersupply kit ?
« Reply #93 on: February 08, 2012, 07:21:25 am »
And then there is the customs hassle, where it really isn't worth my while to ship a blank PCB worth $10 or $20 internationally because of the paperwork involved.

I don't know if it's different in Australia, but isn't it only necessary to fill out the standard customs declaration form and attach it to the outside of the package? For one off shipments you can fill this out by hand at the post office, but for multiple shipments presumably you can print out the forms at home from a template? (The disadvantage is that printed forms may get more attention from the customs inspectors on arrival than hand-written forms, but hey, what are you gonna do?)
I'm not an EE--what am I doing here?
 

Offline EEVblog

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Re: Do you want to buy the powersupply kit ?
« Reply #94 on: February 08, 2012, 07:31:44 am »
I don't know if it's different in Australia, but isn't it only necessary to fill out the standard customs declaration form and attach it to the outside of the package? For one off shipments you can fill this out by hand at the post office, but for multiple shipments presumably you can print out the forms at home from a template? (The disadvantage is that printed forms may get more attention from the customs inspectors on arrival than hand-written forms, but hey, what are you gonna do?)

Yes it's a form I fill out. I have a name/address stamp that helps a lot. But it's also standing in line at the post office and then standing there as they scan and enter each one into the system, weight it, record my ID (yes, another stupid thing no doubt driven by Uncle Sam), print the label and put on various stickers, for each package.
Some employees are more efficient at it than others  ::)
I'm trying to get a way to streamline this, but they are giving me the run-around. So it may get better...

Still not as easy as sticking something in a pre-paid satchel and popping it in the box as I do for local stuff.

Dave.
 

Offline markus_b

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Re: Do you want to buy the powersupply kit ?
« Reply #95 on: February 08, 2012, 07:57:28 am »
Seeedstudio provide a service they call 'Propagate' (Propagate description) where they distribute a device (or kit ?) according to your design. They handle everything, including payment and shipment.

Looks very interesting to distribute a design to a small to intermediate population.
Markus

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Uncle Vernon

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Re: Do you want to buy the powersupply kit ?
« Reply #96 on: February 08, 2012, 08:00:34 am »
I'm trying to get a way to streamline this, but they are giving me the run-around. So it may get better...
Use a decent international Courier and they do it all and pick up from your doorstep. Cheaper too, just avoid the cowboys.
My suggestion (for what it's worth) is to price a few, you may be surprised.
For national deliveries air couriers are definitely cheaper and quicker than Auspost.

Quote
Still not as easy as sticking something in a pre-paid satchel and popping it in the box as I do for local stuff.
Not having to go to a post office, isn't easier?
« Last Edit: February 08, 2012, 08:03:11 am by Uncle Vernon »
 

Offline IanJ

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Re: Do you want to buy the powersupply kit ?
« Reply #97 on: February 08, 2012, 08:06:34 am »
Hi all,

I probably wouldn't buy the kit, but I'm seriously thinking about the design as a basis for a home built PSU. I'm quite looking forward to extending the design to say 3-rail variable. It's been a long time since I built a PSU and it'd be a great wee project.

Ian.
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Offline sonicj

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Re: Do you want to buy the powersupply kit ?
« Reply #98 on: February 08, 2012, 08:19:51 am »
Back when I used to ship a lot, I made a template for CN22 customs forms. Copy, paste, print.
-sj
 

Offline EEVblog

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Re: Do you want to buy the powersupply kit ?
« Reply #99 on: February 08, 2012, 09:43:49 am »
Use a decent international Courier and they do it all and pick up from your doorstep. Cheaper too, just avoid the cowboys.
My suggestion (for what it's worth) is to price a few, you may be surprised.
For national deliveries air couriers are definitely cheaper and quicker than Auspost.

If an international courier can beat Australia posts prices then I'd love to see it.
$12 or so for delivery of the uCurrent to the US.
Yes, a pre-paid international courier satchel would be ideal. Aust-post do offer such things via courier service but the price is ridiculously expensive.

Quote
Quote
Still not as easy as sticking something in a pre-paid satchel and popping it in the box as I do for local stuff.
Not having to go to a post office, isn't easier?

I have to go to the post office anyway for my PO box, and it's only a short walk from the lab or a stop on the way to/from.
Couriers actually have the annoyance of having to be there all day to hand over the stuff.

Dave.
 


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