…mike

Try getting a quote from Lintek on your uCurrent boards to see how they compare to the NZ manufacturer.

IMP still do local manufacturing, but they can also source PCBs from China.

By the way, there are still at least 3 PCB Manufacturers who locally produce boards in Australia: Lintek, IMP and Artronic Productions.

I had forgotten about Artronics, and aren’t Lintek very high-end and uncompetitive for regular boards?
And I was under the impression that IMP off-shored now?

By the way, there are still at least 3 PCB Manufacturers who locally produce boards in Australia: Lintek, IMP and Artronic Productions. I have been using Lintek for over 5 years and their quality is absolutely superb (and they also use the LPI Component Overlays). Lintek make their boards in a completely different way to other manufactures through a process of electrodepositing the copper to the board rather than etching it. This results is very precise track geometries. (http://www.lintek.com.au/unrivalled.html)

There is another prototype service I have recently used called Dorkbot PDX (http://dorkbotpdx.org/wiki/pcb_order), where you pay a flat rate of USD 5 per square inch (you get three copies of each board for this price), with a USD 15 postage fee. The boards are manufactured in the USA, and the quality is also very good (except for the component overlay which uses a silkscreen process). However it can take 3 to 4 weeks to receive the Dorkbot boards.

“Murphy was an optimist…”

I’ve seen that on a T-shirt somewhere…

I love the EEVBlog – I’ve probably learned more about electrical/electronics engineering from you in the last few months than I did while getting my electrical engineering degree!

In this video, you mention Murphy yet again. I thought I would share MY favorite – “O’Malley’s Law”.

O’Malley’s law states: “Murphy was an optimist…”

Keep up the good work, and best of luck to you!

As nearly everytime, again a very nice video, btw. how long does it usually take to produce such a video of 26mins?

What would you guess why are they doing PWM on the original led?

Regards from Germany,
Manuel

It is in fact serial programmable, but only 300Hz agile in each direction (with 32 bit resolution, none-the-less), so not useful for much more than calibration against a GPS locked source.

The unpopulated switch-mode section is for one of the options that allows for the device to be powered from a single 20-35V supply instead of 5V,15V.

The thing on top of the crystal looks to me like a PTC heater. These are barium titanate heaters that can be doped to severely lose conductivity at a specific temperature, so they’re essentially self-regulating heaters. They’re often used for QRSS oscillators as well, since it is a very easy way to oven-regulate a crystal.

Also, note that holes in HASL treated boards may be smaller diameter as the HASL plates the inside of the holes as well. Manufacturers are supposed to account for that, though, but they might always use the bigger drill so they don’t have to have option-specific drill adjustments. Also, some manufacturers have a limited set of drills and will round up, so the fact that one board’s holes were bigger than the other might have been a coincidence of available tool sizes.

Can’t wait for the power supply kit, looks awesome

It would also explain both the more transparent nature as well as the perfectly smooth edges – this is not an old-fashioned silkscreen process, at the very least. The dot-matrix effect you see on the chinese boards is due to the mesh used to create the screen for the printing.

Nice boards, by the way.

It could be that the LCD can’t shunt enough current through the SDA pin to bring it all the way to 0v. Maybe you could try a weaker pullup resistor.

Check out their forums as their userbase are always coming up with fixes.

It is stated that actually a reverse mounded LED is already used.

Great on moving production to a more professional way. I believe that the real benefit of this effort is to make the product available to more people and not just to bring the price down.

My recently bought uCurrent is still on it’s way so I can only judge the performance of the product based on reviews, but I think that the current price is more than ok.

On the other hand I would had re-named the revision as the PCB design was actually modified. Maybe use different revision numbers, on for the electrical design, one for the PCB and maybe one for the case / mechanical design.

Regards Charlie.

I want to work with i2c.
Will I need to upgrade?
Andy

I like the whole design process and i think it is great to hear some of the other considerations, such as case size etc.

However to some extent i mirror DCflux’s comment about the higher voltage ability. Having said that though im looking forward to putting some theory into practice and looking at extending that capability myself, you can never have enough supplies…

did you also consider to use a reverse mounted battery indicator LED? (something like Digi-Key 160-1456-2-ND)

Maybe you also need to change the hole size and the pads of the LED.

I assume that your assembler is currently using normal LEDs and flips them?

I would like to add my advice:

Write or email thank you notes! Personalize the note by bringing up something that you went over in the interview. Very few people send thank you notes so it will help you standout.

Be careful not to talk to much. Yes you have to sell yourself every chance you can but try to zero in what they are looking for. Take the time to fully understand what the position requires and work towards convincing them that you are the best fit. Don’t be afraid to let a moment of silence pass.

Be aware that a large part of what the interviewer is looking for is, how will this person fit into my existing group. Try to bring up how you have worked in teams and what role you had.

Use a good firm hand shake with a look in the eyes.

If presented a business card take the time to look it over and be appreciative that you have been handed it.

Just some of what I have learned over the years…Good luck new EE’s.

Bill

It should theoretically be cheaper, but like you said, you have to buy more parts because some will go to waste… what kind of savings are we looking at?

this blog is very gooooooooooog
very very thanks

But heads up, I think I see an error in the RevB schematic. Check it out: shouldn’t the opamp U3B (for current limiting) have its inputs the other way round? Unless I’m missing something, currently when measured current is lower than the setting, the opamp output goes high and the transistor clamps the voltage down, down, down…

Your benches will eventually need some diagonal bracing or corner gussets to stiffen them up so it’s best to add them now before the joints get sloppy.

If you ever need to work on mechanical assemblies with sharp edges and screw heads, a piece of short pile high traffic carpet such as found in movie theatres will prevent damage to the bench and keep the unit from sliding around.

Most motors in vacuums that plug into wall outlets in the US, speaking in relative integers similar to those used in discussing “digital products,” are AC motors… so they are more like alternating 1′s and -1′s. (For Non-Electrical Folks: Current flows one way [1] then reverses [-1] while still forcing the motor the same direction.) This is certainly NOT digital.

BUT I suppose –using that same “digital speak”– a motor ‘might’ be constructed such that it ran (that is, it rotated) using the “+1″ of AC current fast enough to allow for the motor to gain speed while receiving current (let’s call this “1″ phase), and spin hard and fast enough to turn right past a non-coiled, non-electromagnetized, or turned off portion of the motor (call this the “0″ phase) and right back to the charged “1″ phase that’s receiving EM current.

So then, THIS motor I just described technically now runs on 1′s and 0′s — TADA! It’s digital… AND it’s exactly 1/2 as efficient in speed and up to 1/2 as energy efficient since it would be turning itself completely OFF 60 times per sec (60 Hz in the US) and then having to electrically “restart” the motor 60 times a sec., too.

BUT Why would the “Brilliant Genius” Mr. Dyson built a half-efficient motor? Maybe the same reason a 4th grade science student would… he didn’t understand it!

Only other explanation… just like most other replies, it’s just like any other brushless motor but the Marketing folks know that many (or most) people just don’t know even the most Basic Science.

With that many chips on the bus you will have quite some capacitance. If you want to maintain reasonably clean rising edges you will need a bit of current there.

When routing : use the dasiy chain constraint on SDa and SCL and place the pull up resistors at the last point (farthest away from the cpu) . If the bus is getting to be reasonably long ( let’s say over 10 inches) i typically split the pull ups and put a pair at both ends ( simply double the resistance value at this point. I put two sets of 4k7 giving me 2.35k effective per line ) from a 3.3 volt rail i get nice clean edges with a drive current of slightly over 1.2 milliamps.

just my 2 cents

shift-drag just doesn’t cut the cheese in 3d view.

I am using more and more step files in my designs. a lot of manufacturers have these avialable now for all their parts ( Molex , tyco , Bud and Hammond for their enclosures ) and you can find ton’s of stuff in 3dcontentcentral.com. Most of the time, if you call a manufacturer, they will email you step files. It is becoming more and more prevalent.

are you going to build / review this succer ? and make video…

thanks

However, you should leave your ignorant racist slur off the forum, JeffS.

Keep up the good work,
Allan

thanks for this series of tight technology teaching videos. They cover analog circuitry, SPI, I2C, rotary encoders, signal limiting, overload/reverse current testing and in the future possibly timing issues with I2C or software-SPI. Much we can learn from.
Go on with it!

cheers

Olaf

In a perfect world a single chip would do everything (and it does happen), but where’s the fun in that?

If I was teaching some students and wanted them to get a glimpse of the design process this is what I’d have then look at. I learned some things myself. What more can you ask for?

Fantastic job, keep it up.

…mike

http://timewitharduino.blogspot.com/2009/09/introducing-duino644.html

fchk

fchk

Probably time to put it on separate pages.

Any word on getting a kit put together for this?

I’d love to have one of these but I think your target design was for a maximum output of 10 volts and alot of times I work on stuff that is 12 and 13.8 volts, would it be possible to make it output at least 16V but preferably 20?

http://eevblog.com/uploads/uSupplyBenchRevB.pdf

Please, oh, please.

fchk

Kapton tape’s fairly expensive – I know we used to pay $80 for one roll of it (the thin stuff), so that huge roll and all the other rolls probably account for a good chunk of the cost…

Impressed with the quality of the stuff though.

If so you would be able to post a date when the next batch will be available so that way when a person orders a device / kit they will already know when it should ship out to them.

I of course would pad the date. Everybody loves getting stuff early. It’s always a pleasant surprise however nobody likes getting things late hence the padding.

As for the taking peoples money before you have something to deliver. That’s something you have to work out on your own. I can think of many examples of businesses doing it both ways and for entirely legitimate reasons.

If you really don’t feel comfortable with it you can put it into an escrow account rather than using it to pay for the next (or current) order.

I just see a classic supply and demand problem. It’s obvious there’s more than enough demand since you seem to sell out within minutes to hours with each order. Supply seems to be the issue and I’d rather see you make more money. I’m somewhat surprised their isn’t a secondary market already for the uCurrent devices given the demand.

Just my two bits worth. Take it for what it’s worth.

I really want one. It’d be great buy one + two kits of the new power supply series when it is out. But I’d like to save on shipping by ordering them all together.

Do you think I should sign the list or wait till the power supply kit comes available?

Thanks

Marius

In case of a LDO regulator, the reference voltage[REF] must be applied on inverting(–)
input of the error amplifier because the PNP transistor inverts the phase by 180°, thus the overall feedback should be 180°(negative feedback). Of course, the middle point of the resistive divider should be tied to noninverting(+) input.

No offense meant.

Mihai

this uCurrent is a great idea. It’s remarkable that no one has published such a circuit before.

Best regards,

Thomas

Which appears to have the info needed to make the output variable from around 1K to 15M even has a DOS program for configuring the frequency.

Cheers

Maybe you page doesn’t work with Safari. Amateur-ville.

Dale B

This is the video for the exact same talk… kinda nice to see the slides

Jerald Thomas
jeraldamo@gmail.com

Anyway, it'd avoid having to hold things in front of two different cameras when doing live shows, plus I imagine it'd be more convenient to have your camera on a tripod than using the built-in one on the laptop.

The capture sticks appear as a plain old video capture source in Windows, and should be usable with whatever software you use for the live shows.

Concerning freq references, it would be also clever to avoid the rubidium, and to lock a 10 MHz VCXO on a GPS pps output… advantage : the same uC cold also be used as a freq. meter.

I personally like the idea of RepRap where the printer is built from 3d printed parts and stuff you can buy locally. Also you can print the parts for a RepRap and give them to other people who want to build one, or print improved parts for your own RepRap.

And I thought my Lpro 101 was cheap.
Thank you for the hint, at these prices I immeadetly had to buy one.

I also have a Gps locked Rbidium source from Ebay, but I am not sure if that is more stable than the Lpro 101. Furthermor I do not have the equiment to test the stability. If you have any ideas how to test the stability of an oscillator it would make a great tutorial.
Phase noise measurements would be interesting also.

Cheers
Michael

You may find the details in this link of use in your attempts to understand and control the unit.

Cheers,

Ross

http://www.vk3um.com/Fe-5680A4.pdf

This was also the first time I actually saw the print bed in someone’s hands and wow, it’s tiny! The Ultimaker version is gigantic in comparison. Makerbots new printer seems to be going in the direction of the Ultimaker setup (I know the Ultimaker wasn’t first but it’s my only reference) though and will get a larger print area which is great.

Once you get this thing assembled I’m sure you’ll find yourself coming up with stuff to print that you never thought you’d need. I know I do Right now I’m designing a custom enclosure for a little project I’m working on. The satisfaction you get from designing something on your computer, get it over to the printer, hit print and a few minutes later you have it in your hand… it’s amazing.

And no, I wont be getting any money for mentioning a competing printer so don’t even go there

So whilst I think that they are quite expensive, as to whether they are “overpriced”, well, you’d have to look at the actual BOM cost and profit margins. I don’t have that data. But if they are overpriced, then there is a big market waiting to be tapped for a lower cost / lower margin model.
It’s open source, so anyone can do that….

Good Luck, David in Jakarta

Have the guys at Peaktech in Germany ever sent you anything for review Dave?

I’m very satisfied with my Peaktech multimeter and they’re coming out with an portable LCR meter that does 100 KHz as well next week (in theory).

Would be really nice to see how it compares against the Agilent, being at a cheaper price but with similar characteristics:
http://www.peaktech.de/productdetail/kategorie/lcr-messer/produkt/peaktech-2170.html

On sheet 13 is the pinouts and commands used to talk to it.

If that’s under the foam — no doubt the foam is intended to act as thermal insulation to protect it from thermal shocks.

My daughter got one for Christmas. She loves it. As everyone has already mentioned, the e-ink screen is superior for reading. I no longer use my iPad for reading — and just “borrow” hers after she goes to bed.

@ $99 going to get one for myself.

p.s. Target web site won’t sell Kindle. You have to go into the store for the special price. I live in the Bay Area.

I absolutely love your show. Keep on going!

Excellent video series. Will you be addressing the design of a dual tracking power supply with + and – floating outputs?

Thanks,
Michael B.

This was very useful.