Particle Update

I’ve been ignoring my Geiger counter for awhile now, but I picked it back up and made some progress again. For some reason, I just wasn’t getting the 555 based HV power supply to generate a high enough voltage. In frustration, I bypassed the 555 and fed a PWM signal in from a microcontroller board that I have laying around.

That fixed the problem. I still don’t know why I wasn’t able to the the 555 doing what it was supposed to do. I’ll have to spend some more time on that some other day, but for now, I’ve prototyped it out and I’m happily detecting particles. I whipped out the new layout and will send off to Sunstone.com for another set of PCBs.

I’ve also replaced the Atmel chip with a PIC. I don’t have anything against Atmel. I’m just more familiar with PICs. Once I’ve built a few of these, I’ll change to really small packages — QFNs or BGAs for the chips — to make the board a little more fitting with our assembly capabilities. The SOIC chips are fine, but our machines don’t even come close to breaking a sweat with things that big.

Duane Benson
We treat agoraphobia for PC boards

 

blog.screamingcircuits.com

ValueProto from Sunstone

I think I’m done with the Geiger counter layout. Now I just need to get the thing built up to see if it works. I’m pretty sure, but you never know. I have an idea … I’ll build a prototype. And … I’ll build it in as self-serving a way as I can. How might I build a prototype in a self-serving manner?

First, I’ll use my company (and our partner Sunstone Circuits) to build it. Second, I’ll write about it here. Technically, you’re not really supposed to review your own stuff, but I really don’t get to order things very often. I know all about Sunstones’s PCB fab services, but I haven’t used their ValueProto service so I’m using this as an opportunity to do so. This PCB looks like it should work for their “ValueProto” service as well as with Screaming Circuits’ “SimpleProto” service. Small quantity, no leadless parts. Perfect for the simple and value services.

DPAK in gieger I actually made a small change since I last wrote about this design. The particular high-speed, high-voltage transistor in the original design isn’t available in an SMT package. I could have still left that one part in through-hole, but I didn’t want to so I didn’t. This is one of the reasons I understand the difficulties of parts substitution. I found two similar parts. One in a SOT-23 and the other in a larger DPAK. I really wanted the smaller package, but the specs of the DPAK part were closer. The DPAK is quite a bit bigger than the SOT-23, but it fits.

When I pulled up the layout to take this screen capture, I notices that the “Q1” label was slightly on the big pad for the DPAK. That’s not good. When I find a last minute error like that, I usually take that as a sign to go back and give everything another once-over. I’m going to do that tomorrow, so stay tuned.

Duane Benson
Same bat-channel. Same bat-time. (Different real-time though)

blog.screamingcircuits.com

My Mistake — Naturally

I received my PCBs for this project from Sunstone yesterday at about 10:10. I quickly dropped them into my box of parts and delivered it to the receiving pile-of-boxes in our shipping.receiving department. At 11:40 a.m. yesterday, I received an email from our auditing department informing me of a BoM mismatch.

BOM mismatch Yes. I had made a mistake in my bill of materials. The board has a bunch of yellow LEDs and one red LED. I had mistakenly only packed up yellows. Our audit department caught my mistake and sent me a quick email. If I hadn’t have responded yesterday, I would have received another email at midnight. I could have just told the Downsized_0421110938a manufacturing folks to put a yellow LED in that spot, but the yellows are for a display and the red is a power-on indicator so I got my red LEDs and delivered them to receiving.

This morning I got my assembled boards all nicely wrapped in anti-static bags along with all my leftover parts in their original packaging. Next step, get some batteries and power them up.

Duane Benson
Thor, Dog of Thunder, is not allowed

http://blog.screamingcircuits.com/

Short Cuts Don’t Always Make Long Delays

The saga continues. I have my parts kit. The PCBs should be here from Sunstone tomorrow. When I placed the order on our website, I estimated that I’d have the parts and PCBs today. I knew it would be tomorrow, but I wanted to see how our communications goes when something is late. Obviously, an assembler can’t start building until the parts have arrived, so the Industry standard is to start the turn-time once everything is in the shop.

If a box is late and the sender doesn’t know it, unintended delays can be added into the process. Knowing this, we recently did a lot of work to improve our communications, on such issues as late parts, to help reduce delays. Sure enough, I dropped on over to the website and right on the top of the home page is a note that I have an issue (late parts) with my job. Tonight at midnight, I should receive an email telling me the same thing too.

On the subject of the PCBs, I sent Gerbers to Sunstone. That works just fine, but I’m always a bit nervous about the accuracy of my layer mapping. They double check, so I’ve never had problems, but I still get nervous.

If I’d waited a few days, like until today, I could have taken a short cut by just sending in my CAD board file — they just started accepting native CAD files. You can still use Gerbers, but if you use Altium, Eagle, OrCAD, National Instruments’ Circuit Design Suite, Ivex Winboard or PCB123, you can just send in the board file and save some time and hassle.

When I get the boards tomorrow, I’ll pack everything up and deliver it to the receiving folks. Then I’ll see how the rest of the build process goes from the other side of the fence, and I’ll see how we deal with extra parts. I did that on purpose also. With a couple of parts, I’m delivering several hundred more than I need. With a few other, just the requisite 5% over. It will be interesting to see just how I get the extras back.

Yes. I know. I work here, so I shouldn’t have any doubt about how all of this stuff works. I do know how it goes, but it’s always a good thing to, every now and then, check and see how well practice matches up with theory.

Duane Benson
Grip, Fang, Wolf! Guard the mushrooms!

http://blog.screamingcircuits.com/

Sunstone’s ‘Fab’ Design Tool

Sunstone is again acting as much like a software company as it is a quickturn PCB fabricator.

The board shop, which over the past few years has developed and honed its free CAD/DfM tool known as PCB123, today rolled out a conversion tool that features native file upload functionality.

In short, customers no longer need to export data in Gerber; instead, they can use one of a series of native data formats, including Altium, Eagle, OrCad, NI, and others (including, of course, PCB123).

It’s the second big development by the PCB maker in the past year, having already rolled out a parts library addition to PCB123 that supports some 500,000 components.

PCB123 won’t replace the big ticket CAD suites, of course, but for the types of prototype boards most designers need, it keeps getting better and better. And with its CAD conversion capability, Sunstone further extends its “ease” factor to those who don’t use the company’s own software.

Chowing Down

I don’t know how common the phrase “eating your own dog food” is. I know I’ve heard it before in some of those obnoxious business seminars. Not all business seminars are obnoxious. Some are quite helpful and actually, now that I think about it, I’m not really sure if I’ve heard the phrase in the obnoxious seminars or the useful ones. Maybe the so-so ones. Hmm.

Anyway, in case you haven’t heard the phrase (it may be a regional thing), it means to use your own product, or in our case, service. I’m not an engineer, but I play one on the Internet. Still, I design and build little things. Since generally what I build is hobby-related, I tend to solder them up myself, leaving our capacity here at Screaming Circuits for the paying customers. But right now, I’m doing something a little different.

SC Promo 042011 top layer I’ve got a little design that I’m going to use to help some folks better understand how things work around here. At first, I’ll just give it to some writers and editors (writers and editors, feel free to shoot me an email about it), but at some point, I hope to be able to have enough to send out to design engineers that want to get a feel for our process. It’s quite a simple board” a PIC microcontroller (18F25K20 SSOP), some switches, resistors, a bunch of 0603 LEDs and some bypass caps. One Schottky diode too. I’m putting together a sample kit just like the sort of kit we like to receive. The files will be on a Screaming Circuits USB drive. The PCB, fabbed at Sunstone.com, will be in there. All the parts, purchased from Digi-Key will be in individual bags; one per BoM line item.

The idea is for someone to take the kit as though it were theirs, create an account on our website, quote the job, place the order (no payment needed), upload the files and send in the kits. Along the way, that person will see what we like to see in a parts kit and how the whole register, quote and order process goes. Once they receive the working board back, all they have to do is decode the secret message it displays.

Back to the dog food. From my side of the Interpipes, it’s easy to say that things are easy. I sit back, drinking lattes and eating oatmeal while everyone else does the real work. But during this process, I’ll get a refresher course on what it’s really like to get a prototype built.

The other day, I sent the Gerber files off to Sunstone to get the PCBs fabbed and the parts order off to Digi-Key. Tomorrow, I’ve got to kit everything up. Stay tuned. Details as events warrant.

Duane Benson
Is this the kind that makes gravy when you pour water on it?

http://blog.screamingcircuits.com/

Parts Time

Sunstone this week released v4 of its award-winning PCB123 CAD tool.

The no-cost, license-free tool features parts outlines for 500,000 components, automated BoM and integrated DRC/DfM rules. But what’s most interesting is that users can automatically get availability and pricing info for each component registered in Digi-Key’s database.

This development is fascinating in two respects.

First, that a modest-sized PCB fabricator, not a billion-dollar EDA company, is pushing the envelope on electronics design software.

Second, for engineers who now must not only draw the electrical circuit but also lay out the board and order the prototypes, built-in parts procurement is a huge time saver. Which begs the question, why aren’t the big CAD companies offering this too?

Newark Electronics and Eagle CAD — Interesting

I just read that Newark purchased CadSoft, including Eagle CAD. I guess it’s probably old news to everyone but me. The press release about it that Newark posted on its website, Element 14, has a date of Aug. 13. I find this purchase an interesting development and I don’t quite know what it means, or if it means anything.

I guess partnering is becoming a trend. Certainly, we’re involved in some good partnerships (Sunstone, Digi-Key, NXP, National Instruments) and Sunstone’s PCB123 connects up with Digi-Key parts. It does make sense. The engineer’s job has just gotten more difficult with this recession and the ensuing reduction in support staff. That’s pretty much what our ECOsystem partnership is all about — taking the disparate tasks involved in getting a prototype built up and reducing the steps and complexity involved in the process.

The Eagle / Newark deal does have me very curious. For one, I hope the CadSoft folks got a good deal. Their product has done a lot toward lowering the barriers to electronics design and they deserve a lot for that. The big questions are for the future. Will Eagle remain as accessible as it is? Will Newark throw a lot of resources into it and keep it moving forward? Will it get good attention or will it be treated as an impulse buy and not be given focus or direction? Hmmm…

Duane Benson
What about Element 32?

http://blog.screamingcircuits.com/