Meeting #5 Announcement - Locating Intrusions Using Fiber Optics

Update: A meeting recap.

EAST Knowledge is excited to announce it's fifth meeting. Jim Rulla will be giving a talk about how fiber optics can be used as sensors for locating intrusions. Come and learn something new! Come and share what you know! All are welcome!

What:	Locating Intrusions Using Fiber Optics
Who:	Jim Rulla
Where:	The Story Room at the Gresham Library (map)
When:	10:30am-Noon, Saturday, April 18th, 2015
Why:	Sharing what we know

Interferometers measure distances to within fractions of the wavelength of light. Put a couple of these incredibly sensitive devices on the fence around an airport, and you can not merely detect a would-be intruder — you can locate him. Put a pair on a pipeline, and you can not merely detect nearby digging that could damage the pipe — you can locate its source. You might even be able to detect — and perhaps even locate — leaks in the pipe.

The detection and location mechanisms are fascinating examples of clever engineering. I'll explain how these patented systems work and illustrate new algorithms that improve performance.

Coffee Break #2 - Recap

We held our second Coffee Break at the pleasant Cafe Delirium. As usual, we had a friendly group show up. We forgot to take pictures this time, but that's only because we were engrossed in our conversations. I attempted to gather notes about what was discussed, but I admit that I didn't start taking notes until late into our conversations.

• Discussed Jim Rulla's upcoming talk Locating Intrusions Using Fiber Optics. I hope to get an email announcement out in the next few days.
• Discussed some of the differences and challenges between the industry in China and industry in the US.
  • Discused some of the strange economics that come into play. For instance being able to do three turns of a circuit board (assuming you have the time and right quantities) using manufacturers in China with less money than it would take to do a single turn in the US.
  • Andrew "bunnie" Huang's efforts to reverse engineer a SOC From Gongkai to Open Source. Choice quote: "I want to be able to use a 364 MHz 32-bit microcontroller with megabytes of integrated RAM and dozens of peripherals costing $3 in single quantities, instead of a 16 MHz 8-bit microcontroller with a few kilobytes of RAM and a smattering of peripherals costing $6 in single quantities."
• Brought up how current chip manufacturing is handled by robots with the silicon wafers being placed and handled in large caddies (called FOUPs) where a single caddy of finished chips can represent several tens of millions of dollars. This reminded somebody of a video presentation that included a clip of an incident in a plant. (The whole video is worth watching.)
• Discussed the use of Cython which Pat may try to incorporate into a future talk.
• Pat brought up how you can combine Encfs with a Dropbox-like service to create an encrypted volume that is synchronized to the cloud without the cloud being able to see what is stored.
  • This is easily used under Linux with FUSE, but apparently there is an equivalent option under windows called Dokan.
• We briefly discussed the potential to use a Raspberry Pi as a media center PC. It was also mentioned how easy it is to change the "personality" of a Raspberry Pi by swapping SD cards. This allows you to quickly repurpose a Raspberry Pi.
• Some amount of discussion about how small technology companies can contribute meaningfully to local economic development. We stressed how small companies and individual consultants often service larger companies.

That's all I can remember for now. If there's anything you'd like me to include, please don't hesitate to mention it. Thank you to everybody who came out. And if you couldn't make it, we hope to see you next time at one of our regular meetings!

Coffee Break #2

Update: A meeting recap.

EAST Knowledge is pleased to announce it's second "Coffee Break"!

EAST Knowledge is going to try a repeat of our first "Coffee Break". The first had a lot of great discussions. We invite you to join us for coffee at Cafe Delirium. We have the room in the back reserved. We're going to hang out for a couple of hours, so feel free to come by, talk shop, show off what you're working on, ask questions and pick each other's brains. We look forward to seeing you there! All are welcome!

What:	Coffee Break
Where:	Cafe Delirium
	308 N Main Ave, Gresham (map)
When:	10:00am-Noon, Saturday, March 28th, 2015
Why:	Sharing what we know and what we're up to

Meeting #4 - Recap

To celebrate a year of EAST Knowledge, Pat Nystrom returned for meeting #4 where he showed off two things:

1. Recent work on his pick and place machine
2. A DIY solder mask application

Pat is an engaging, knowledgeable speaker and he gave a tremendous talk. As usual, we’ll do our best to capture the meeting in these humble notes, but we won’t pretend to do the speaker justice. You really have to see these presentations in person.

Pick and Place Machine

When Pat last talked at EAST Knowledge he showed us his nearly completed pick and place machine. Pat’s goal is to produce a low cost pick and place machine for hobbyists and prototype assembly. He wants to combine what people do best with what machines do best. His pick and place machine will allow the human operator to pick up parts, while letting the machine perform final placement.

However, before finishing his machine, Pat was contacted to perform some other work that had extremely tight deadlines and required PCB assembly of multiple boards. The deadlines were so tight that he would not have been able to have the PCBs assembled by a manufacturing firm, so Pat turned to his mostly finished pick and place machine to assemble the boards himself. However, he found that while his current pick and place machine had buttery smooth motion when manually operated (as intended), it did not have the fine control he desired for part placement while being operated manually.

Manual Pick and Place

So Pat put together a new pick and place frame. For the two axes, this has rigid arms with small rollers that can be manipulated with the fingers for fine adjustment. Each axis has just enough stiction to keep from moving while the other axis is being adjusted. Additionally, Pat outfitted the parts head (taken from the previous machine) with a digital camera that he could use to see where the part was while placing it.

The machine isn’t perfect. For instance, the camera doesn’t have a perfect view of the part needle, so getting used to where the needle would place the part required a small learning curve. Despite the limitations, the machine allowed Pat to stuff 16 boards with small scale parts in about 4 hours without the fatigue and mistakes he would’ve experienced had he been using magnifiers and tweezers. Additionally, he successfully completed the prototypes. It’s hard to argue with success.

For the future, Pat would like to add a second camera to the head to provide a better view, and a laser dot that will provide an easy way to see where the part will be placed.

Lessons Learned

Beyond the technical issues, Pat felt he learned some valuable lessons while working on the manual pick and place. Being forced to work quickly required him to come up with ideas that he could try out quickly. This rapid pace allowed him to discover bad ideas earlier and discard them. Whereas before he was trying to get to product completion quickly, he is now thinking more along the lines of iterating his way to product refinement. Additionally, the manual pick and place is useful as it is right now even without all the automation. Focusing on having a useful product at each stage of development also allows for rapidly trying ideas.

It appears that the pick and place machine itself feeds into Pat’s entire process. It allows him to rapidly try ideas on not just the pick and place machine but also on the other things he works on.

DIY Solder Mask Application

After showing us his work on the pick and place machine, Pat gave a demonstration of a method he has developed for applying solder masks to his prototype circuit boards. Pat mills his own circuit boards, but the method will apply to any circuit boards you may make or have made. While you don’t need solder masks just for a prototype board, having a solder mask:

• Improves the reliability of the board
• Increases the lifetime of the board
• Makes it easier to rework the boards

In short, it is often better to have a solder mask, so being able to apply a solder mask to boards you make yourself is a boon.

How it Works

Pat found a source of solder mask material that comes as a sheet. One side of the sheet is adhesive. This material is light sensitive, so Pat keeps it rolled up in a tube.

Required materials and tools:

1. Solder mask material
2. Solder mask stencil (it’s black everywhere you don’t want solder mask, i.e., over the component pads)
3. Exposure frame
4. Laminator (Pat used a Harbor Freight laminator)
5. UV Light source (Pat used a lamp that is normally used to cure finger nail polish)
6. Masking Tape
7. Exacto blade
8. Scissors
9. Latex gloves (mostly for cleanliness)
10. Canned air

Steps:

1. Warm up the laminator.
2. Wash PCB and dry with canned air.
3. Cut a piece out of the sheet of solder mask material to be bigger than your PCB. Pat used scissors to get a rough cut.
4. Using masking tape, attach to the dull side of the solder mask sheet, and pull off the protective covering. This exposes the adhesive side.
5. Apply the adhesive side to the PCB.
6. Use the exacto blade to trim off the excess material.
7. Run the PCB through the laminator. This will cause the solder mask material to adhere to the PCB surface.
8. Tape the stencil to the bottom of the exposure plate. Make sure the ink side of the stencil is away from the plate (which will be towards the PCB).
9. Close the exposure plate down over the PCB and align the PCB to the stencil.
10. Once the stencil and PCB are aligned. Clamp the exposure plate down so that the PCB won’t move.
11. Place the PCB into the UV light source for about 2 minutes. Let cure for another 5 minutes (optional).
12. Remove the PCB from the exposure frame, and lift the top protective sheet from the solder mask.
13. Use sodium carbonate and a brush to remove uncured solder mask material. Anywhere the UV light was blocked by the stencil should come right off.
14. Rinse the board again.
15. Enjoy your freshly solder masked PCB!

Pat was talking to the group as he demonstrated his method, but it looks like it only takes a few minutes of work to apply the solder mask.

Exposure Frame:

Stencil:

The UV source being applied to circuit board in the exposure frame:

The circuit board with solder mask applied. The green areas are where the solder mask stuck, and the copper areas are just the bare circuit board:

This was another excellent demonstration of Pat’s methods for quickly bringing his circuit ideas to life.