31
General discussion / Re: Nice & cheap finds at eBay
And heat your home in winter :-)
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Messages - sleemanj
And heat your home in winter :-)
32
Tools of the trade / Parallel Resistor Network Finder from Personal Stocklist
So anyway, long story short, I wrote my own equivalence finder that considers only those resistors you actually have, and figured somebody else might find it useful, so I put it on the interwebs -
Equivalent Parallel Resistor Network Finder Using Your Personal Stock List Of Resistors (it's a mouthful, but trying to be friendly to the future googlers here).
Caution, you should use Chrome for best results. Firefox works as long as firebug is disabled. No idea what IE will think of it all.
Scroll down the page to enter in the base values you have decades/partial decades of. Select the number of decades you usually keep. Enter in any holes in your decades. And any bumps outside of the decades. You can hit the "Save (sort of)" button and bookmark the result for next time.
Once you've described your resistor stock, you can search for a desired value (you can enter it in the usual various styles people use - 1.0, 3k7, 1.5M, 0R5, 0.5R, 762913 ... you get the idea), specify how much error you will tolerate, choose when the search should give you a less-precise but less-resistors solution, the maximum number of resistors per stack, and if there are no solutions within your error tolerance you can select a Last Resort option to look for a solution of two parallel stacks in series.
NB: The first time you hit Search it builds an array the possible stacks, so that can take a few seconds depending on the Maximum Stack setting.
Anyway, there you go, hope somebody else finds it useful :)
33
General discussion / Re: Shipping costs Seeed vs. Smart-Prototyping
That seems like an incredibly good price to me. Just going by the rates offered by Taobao agents they much closer agree with the Seeed prices you quoted.
34
General discussion / Re: Taobao Agent Experiences/Reviews for Electronics Purchas
I'm using Bhiner regularly (see my earlier review), despite the apparent more expensive shipping, I find it works out pretty well, they are good to deal with and their system works well. But remember, you are still dealing with Taobao sellers at the end of the day, and that Bhiner (or any agent) doesn't no squat about what you're buying, they can only do the most rudimentary check, and even then they might miss an item or confuse two items that look identical when they are checking the order.
Most of the time, it works out great, it's like Xmas opening and sorting a big box of stuff every month :)
But you do get some "mistakes" that you just have to chalk up to "eh, it's China, what do you expect".
Some of the "errors" in the order I have encountered:
A strip of 1206 LEDs missing - I'd ordered 5 different types, only 4 different types arrived, I think they probably got confused because one was "green" and one was "yellow-green" (or greenish-yellow if you prefer). If you are ordering a selection of the same things, try and find a seller that has already packaged and is selling it as that selection - eg, in this case, I later found a seller that has exactly the selection of 1206 LED's I wanted (RGBWY) being sold as a package, very unlikely to be any problem that way, but if you order individually, good chance one might not make it.
Miscounts also occur, one missing here or there, but usually balanced by an extra one of something else.
Something being sold as something it's not, I bought what I thought were something like ink brayers, and were being sold as something like that, for rolling soldermask ink onto pcbs. When they arrived they were (now very expensive due the shipping) clothes lint rollers. I later re-translated and read the comments from other buyers and one mentioned something like this. Take care that you are pretty sure of what you are buying.
Sometimes it works out the other way though, I thought I was buying 6 packs of 200 "1%" resistors (a 6 digit decade) for 0.84 USD/200, what arrived was 6 full boxes of 1000 "1%" resistors for 0.84 USD/pack (so instead of 1200 resistors I wound up with 6000!). Now to be fair this meant that the shipping was more than it should have been, and the "1%" is rather subjective (I suspect these are 5%, but a good number do hit within 1% or bang on, with my cheap multimeter), but still.
The wrong but similar thing gets sent. I ordered (as a test really) some SMD ULN2003 and MAX7219 chips. What arrived was DIP versions of the same. Not a big loss, except...
[attachment=1]
Yep, they were plugged into polystyrene and wrapped with clingfilm and tape.
Now I had specifically ordered SMD varients because I had anticipated that there might be poor shipping practice for DIPs, while SMDs come on tape (or whatever you want to call the individual plastic enclosure feed reel stuff) which at least provides a little "built in" protection.
Except I also ordered some L9110S (full bridge drivers) SMD, and they came like this...
[attachment=0]
You'd think that any seller who sells electronic components would at least try to look like they know what they are doing when shipping.
Then again, some sellers really really do a great job, I bought some Piranha led's of different colours, each colour came in a sealed and labelled anti static bag. Some buck converters, individually sealed into anti static bags, they don't even really need that.
All in all, buying from Taobao is kind of fun, there's deals to be had, and massive loads of time to be wasted just browsing the stores trying to "devise" your order to be as efficient as possible, and then having to start again because you stumble across something else that you just HAVE to get in there but you're already pushing up against the customs limit (here in NZ, $400) for a single order before your government will charge you taxes....
35
Project development, ideas, and suggestions / Re: Chinese Soldering Iron Driver (Warning/Info Search)
The handle cost me $1.99 USD + the various shipping & fees (the final price about $6.00 USD, part of a larger order)
The extra elements cost me $0.42 each + the various shipping & fees (final price about $0.91 USD, part of a larger order)
So ignoring my mistaken Hakko handle purchase, total cost to me was about $30 USD, plus the old laptop power supply from my junk drawer.
36
Project logs / Re: USB LED Matrix Controller Board
37
Project development, ideas, and suggestions / Re: Chinese Soldering Iron Driver (Warning/Info Search)
The following are the setting instructions in Simplified Chinese which I extracted from an image and cleaned up. Unfortunately it's still too hard to get a very useful OCR of this to work well, let alone machine translation.
Perhaps somebody who knows somebody who can read Simplified Chinese could translate this.
[attachment=1]
This is the "best" machine translation I could get,
Code: [Select]
Vibration Sleep
= TI2 mild control l do not change u
Coding or press
Type, 0 = imports TL2, non-0 = domestic T12
Potentiometer, non-zero
In seconds, the default time for the Chi cell
0: NC Sleep, Sleep: normally open, 2 setting [] = L0AD factory settings, non-0: Normal mode
Fixed temperature probe for thermal resistance, leave it 0
Type, 0 Single
Class l the seed storage Bu l group of people the m probe by the branded side deep sting Mian Mian temperature for summer and warm in normal operating doors ggg control recovery
The lie. The the L_ very few fq Shanzhunxunyan. Qiu
I believe that [s:]the first item (0)[/s:] item 4 is to do with selecting the sleep switch, either microswitch or vibration sensor. And I can see there is some sort of temperature probe setting, adjusting PID perhaps.
[attachment=0]
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Project development, ideas, and suggestions / Re: Chinese Soldering Iron Driver (Warning/Info Search)
Yep. It definately is. I did some more research on the matter after my post, and actually there's a mention here I think by Arhi that there is a big difference between the thermocouple characteristics in the Hakko 907 and the knock-offs.
The knock-offs are N-type (from memory) thermocouple and can be identified by a resistance around 2 ohm, the resistance of the Hakko's is much higher (60 ohm from memory).
Anyway I'm going to order a couple of the knock-off elements ("A1322") (for a buck a piece or something) to confirm, later in the month. But 99% sure that's what the issue is.
PS: Anybody reading from NZ who might want one, let me know, loosely thinking about importing a few for resale if they prove to be decent enough.
39
General discussion / Re: Taobao Agent Experiences/Reviews for Electronics Purchas
I'll have a look at some of these websites provided to see if they have some service to shop to HK at least for those items that are not excluded from shipping, where it's simply the seller that just doesn't want to bother calculating the shipping cost for Hong Kong.[/quote]
Many agents will ship to you domestically, mainly for English speaking ex-pats living in China/Hong Kong who can't deal with the sellers directly in Chinese.
Just make sure you tell the agent that it has to go through the agent warehouse before coming to you otherwise the agent might ask the seller to ship directly to you (and tell you it's not available when they refuse).
40
General discussion / Re: Taobao Agent Experiences/Reviews for Electronics Purchas
I clicked to sign in with Google, it seemed to created an account for me from my Google+ profile, no invite required. Haven't actually used them though, the quoted $1000+USD shipping charge for less than 1 gram of PCB rivets which could fit on my thumb puts me off a bit :)
41
Project development, ideas, and suggestions / Re: Chinese Soldering Iron Driver (Warning/Info Search)
"HI, it dont work with 907"
I thought the 907 handle was the usual handle for the 936 station. I don't think there actually is a 936 handle.
....oh...wait...a...second....
I wonder if by 936 they actually mean the Atten (and various other chinese brands) 936 handles, they have an inverted connector (where the Hakko has male, the Atten ones have female), I had assumed that these would simply be Hakko copies, but perhaps they have different thermistor characteristics too...
Hmm, I bet that's it actually. Will try and add an atten 936 handle to my next order, or perhaps from ebay.
42
Project development, ideas, and suggestions / Chinese Soldering Iron Driver (Warning/Info Search)
So a while back I bought one of these on Taobao...
[attachment=0]
http://http://item.taobao.com/item.htm?id=8686679296
68 Yuan, which with the shipping and agents etc came to about $17 USD in a larger order, worth a punt. Subsequently I found that these are also sold on eBay http://http://www.ebay.com.au/itm/Soldering-Iron-Station-Temperature-Controller-For-HAKKO-936-T12-T1-T13-Handle-/170969190905?pt=LH_DefaultDomain_0&hash=item27ce8ed1f9&_uhb=1#ht_7058wt_1399
The Taobao seller also has a mini version of it, and sells built up in cases also...
The silkscreen (and a display on the 1602 LCD) says it is "BG2001_V2" "By_LET".
Anyway, supposedly (in so far as Google translate would allow) this supports standard Hakko 936 irons (and the T12 type which seem to be the most common in China for some reason), also supports 4 presets, automatic sleep, DC input in a wide range, input via encoder or buttons. I have finally got around to wiring it up as best I can figure from the diagram. It detects a Hakko 907 handle as a 936 ok, and drives the element, unfortunately it just doesn't seem to be able to read the thermistor at all, the iron temperature readout seems locked to the ambient temperature (but the iron heats up in a matter of seconds, it's not a delay thing, the element is being driven flat out at 100% PWM).
It DOES know the thermistor is there, if I disconnect it, it reverts to T12 mode. I tried putting a pot in place of the thermistor connection and twiddling that flips between 936 and T12 mode around 300 Ohm I think (more becomes T12 and the iron temperature indication changes, less becomes 936 and the iron temperature display seems to lock to ambient [and drives at 100%]). So far as I know the handle's thermistor is working - at least, the resistance across it changes with the application of heat to the tip of the iron. I think the 907/936 irons are just a simple thermistor.
What I suspect, is that the controller simply doesn't support 936 handles (907 etc) properly, since it seems everybody in China uses the T12 based irons. All the images show T12 irons in use, none show 936. So yeah, a warning, if you want to use a Hakko 900 series handle, these controllers possibly don't work as best I can figure, despite what they sellers say.
I guess it could be a configuration thing that has to be twiddled - if you hold the encoder button when powering up you enter a config mode where there are 7 different options you can change, some of them I have worked out, but some are just a number without any sort of notion was to what they do (if anything). So, if anybody has bought one of these (I see the ebay seller has flogged off a few of them) and had success with a 907 handle, please post below!
43
Project development, ideas, and suggestions / Re: Corflute Project Enclosure
[attachment=0]
44
Project development, ideas, and suggestions / Re: Corflute Project Enclosure
45
Project development, ideas, and suggestions / Corflute Project Enclosure
So, I present, Corflute as a simple DIY project enclosure material, all you need is hotglue, and a knife :-)
[attachment=2]
[attachment=1]
[attachment=0]
Corflute is the (genericised brand name) fluted plastic board which real-estate and event type signs are made from. Indeed, I made my simple square enclosure out of old signs which I got for free, real estate companies usually give away their old signs, or just grab an event sign which has been left around after the date. Even if you can't find some old signs, this stuff is ridiculously cheap to buy.
I used 5mm variety, the really nice thing is that it's 5mm square, that is, each flute is 5mm on each side. This makes it very easy to cut to just the size you want, and makes the corners bend really nicely, just cut out the 5mm slice from one side of a flute, then bend, you get a nice curved corner.
At the join edge I left a 5mm flap to cover the end, then just hotglued togethor. For the caps on each end of the cube I cut a square of corflute to fit exactly inside the box, with a flap 5mm larger in each direction. The bottom I glued in, the top I left unglued, it's a tight "snap" fit to allow for access.
To hold the board, a couple of ledges were hot glued inside the box on which a shelf sits that the board is screwed to. I grabbed a handy spray can and painted the box before final assembly.
Working with corflute is very quick and easy, and it's also very strong, and doesn't look bad either, even for a ham-fisted fellow like me.