Portable flexible electronic circuit board Wearable Application introduce

Engineers at the University of California San Diego have developed a flexible wearable sensor that can accurately measure a person’s blood alcohol level from sweat and transmit the data wirelessly to a laptop, smartphone or other mobile device. The device can be worn on the skin and could be used by doctors and police officers for continuous, non-invasive and real-time monitoring of blood alcohol content.

The device consists of a temporary tattoo—which sticks to the skin, induces sweat and electrochemically detects the alcohol level—and a portable flexible electronic circuit board, which is connected to the tattoo by a magnet and can communicate the information to a mobile device via Bluetooth. The work, led by nanoengineering professor Joseph Wang and electrical engineering professor Patrick Mercier, both at UC San Diego, was published recently in the journal ACS Sensors.

“Lots of accidents on the road are caused by drunk driving. This technology provides an accurate, convenient and quick way to monitor alcohol consumption to help prevent people from driving while intoxicated,” Wang said. The device could be integrated with a car’s alcohol ignition interlocks, or friends could use it to check up on each other before handing over the car keys, he added.

“When you’re out at a party or at a bar, this sensor could send alerts to your phone to let you know how much you’ve been drinking,” said Jayoung Kim, a materials science and engineering PhD student in Wang’s group and one of the paper’s co-first authors.

Blood alcohol concentration is the most accurate indicator of a person’s alcohol level, but measuring it requires pricking a finger. Breathalyzers, which are the most commonly used devices to indirectly estimate blood alcohol concentration, are non-invasive, but they can give false readouts. For example, the alcohol level detected in a person’s breath right after taking a drink would typically appear higher than that person’s actual blood alcohol concentration. A person could also fool a breathalyzer into detecting a lower alcohol level by using mouthwash.

Recent research has shown that blood alcohol concentration can also be estimated by measuring alcohol levels in what’s called insensible sweat—perspiration that happens before it’s perceived as moisture on the skin. But this measurement can be up to two hours behind the actual blood alcohol reading. On the other hand, the alcohol level in sensible sweat—the sweat that’s typically seen—is a better real-time indicator of the blood alcohol concentration, but so far the systems that can measure this are neither portable nor fit for wearing on the body.

Now, UC San Diego researchers have developed an alcohol sensor that’s wearable, portable and could accurately monitor alcohol level in sweat within 15 minutes.

“What’s also innovative about this technology is that the wearer doesn’t need to be exercising or sweating already. The user can put on the patch and within a few minutes get a reading that’s well correlated to his or her blood alcohol concentration. Such a device hasn’t been available until now,” Mercier said.

How it works

Image

The alcohol sensor consists of a temporary tattoo (left) developed by the Wang lab and a flexible printed electronic circuit board (right) developed by the Mercier lab.

Wang and Mercier, the director and co-director, respectively, of the UC San Diego Center for Wearable Sensors, collaborated to develop the device. Wang’s group fabricated the tattoo, equipped with screen-printed electrodes and a small hydrogel patch containing pilocarpine, a drug that passes through the skin and induces sweat.

Mercier’s group developed the printed flexible electronic circuit board that powers the tattoo and can communicate wirelessly with a mobile device. His team also developed the magnetic connector that attaches the electronic circuit board to the tattoo, as well as the device’s phone app.

“This device can use a Bluetooth connection, which is something a breathalyzer can’t do. We’ve found a way to make the electronics portable and wireless, which are important for practical, real-life use,” said Somayeh Imani, an electrical engineering PhD student in Mercier’s lab and a co-first author on the paper.

The tattoo works first by releasing pilocarpine to induce sweat. Then, the sweat comes into contact with an electrode coated with alcohol oxidase, an enzyme that selectively reacts with alcohol to generate hydrogen peroxide, which is electrochemically detected. That information is sent to the electronic circuit board as electrical signals. The data are communicated wirelessly to a mobile device.

Putting the tattoo to the test

Researchers tested the alcohol sensor on 9 healthy volunteers who wore the tattoo on their arms before and after consuming an alcoholic beverage (either a bottle of beer or glass of red wine). The readouts accurately reflected the wearers’ blood alcohol concentrations.

The device also gave accurate readouts even after repeated bending and shaking. This shows that the sensor won’t be affected by the wearer’s movements, researchers said.

As a next step, the team is developing a device that could continuously monitor alcohol levels for 24 hours. Source:ucsd

Flex PCB experts give their suggestions in FPC design

This post will discuss some FPC drawing requirements.
And our flex PCB experts also give their suggestions in FPC design.
Go deep to read about Flex PCB design experts recommends Seven FPC drawing requirement guideline.

1. The Basics

First and foremost, there are several board elements that must be included in your design. These include:

Layer count

Finished board thickness

PCB materials used

Surface finish

These may seem like obvious requirements, but they occasionally go overlooked. When that happens, the PCB manufacturer will need to follow up for clarification, delaying turnaround time.

2. A Drill Symbol Chart

The drill symbol chart indicates all of the finished hole sizes, as well as the hole size tolerance, for your circuit board design. The standard finished hole size is +/- .003,” but this is never assumed, so this measurement must be stated on your design drawing.

“The dimensional drawing should define the rigid to flex interfaces.”

3. Dimensional Drawing

The dimensional drawing identifies a number of critical measurements for the PCB design. Notably, the dimensional drawing should define the rigid to flex interfaces, noting where these two types of material meet. While the typical outline tolerance is +/- .010″, it is imperative for the designer to determine and clearly state whether this meets their specific needs. If a pallet or array is needed for the design, a dimensional view is also required.

4. Board Construction and Layer Order

This documentation differentiates between layers comprised of rigid material and layers containing flexible material, such as copper weights. Without these drawings, the PCB manufacturer will need to follow up with the customer, delaying turnaround time.

5. Notes

Along with the flex PCB drawings themselves, you’ll need to present accompanying notes when submitting your circuit board design. These notes should encompass a broad range of specific details. For example, your notes should state:

Class, wiring type, and installation use requirements

Electrical test requirements

Packaging and shipping needs

The notes should also include specific design requirements, but that point deserves its own section.

The more detailed your notes, the better.The more detailed your notes, the better.

6. Specific Design Requirements

In many cases, particularly when it comes to prototypes in areas like the Internet of Things, you’ll have unique PCB design requirements that do not fit into any of the above categories. In order to maximize quickturn benefits, these need to be presented as part of the design drawings early in the design process. Communication between designers and fabrication houses before designing begins and throughout the manufacturing process will speed the process even more, allowing for no confusion or delays.

7. Flexibility

This last drawing requirement isn’t what you think. We’re not focused on the flexibility of the PCB, but rather the design itself.

Writing for Engineering.com, Kagan Pittman noted that it impossible for engineers and designers to accurately predict all of the potential ways that a circuit board design could go awry.

Sometimes, designers will refuse to alter their designs, even when the PCB fabrication partner offers manufacturability or reliability suggestions. Industry expert Al Wright told Pittman about one such instance he ran into where the client, instead of adapting, went to another manufacturer. As a result, the PCB produced was completely faulty. If you’re not sure whether the suggestions made will be applicable to your design, ask the fab house to elaborate on the potential issue.

The purpose of these drawing requirements is to help you make the most of your partnership with a PCB manufacturer. If you’ve chosen an industry-leading PCB firm to work with, then you should absolutely take advantage of the expertise and guidance they offer. That means you need to be flexible and open to suggestions. Source:Sierra