Design Mistakes You Must Avoid on Your New Electronic Product

Summary

In this informative video, John Teal of Predictable Designs identifies 10 common mistakes in electronic hardware development, covering both technical and general design issues. He emphasizes the importance of designing for manufacturability, correct wireless circuit design, early cost estimation, and independent design reviews. Teal also addresses specific technical pitfalls such as improper PCB trace width, decoupling capacitor placement, and enclosure manufacturability. His insights aim to help engineers avoid costly errors and streamline the product development process.

Takeaways

• 🛠️ Design for Manufacturability (DFM) is crucial as it can significantly impact the time and cost of bringing a product to market, and should be considered from the early stages of product design.
• 📡 Proper PCB layout for wireless circuits is critical for maximum power transfer. Impedance matching with a 50-ohm transmission line and LC matching circuit is necessary for optimal performance.
• 💰 Estimating manufacturing costs early can prevent costly redesigns later. It's possible to make accurate cost estimates before the final product design is complete.
• 🔌 Ensuring sufficient width for high current PCB traces is important to avoid overheating and to safely carry the required current.
• 🔍 Getting an independent design review can help catch and correct potential mistakes before they become costly in terms of time and money.
• ⚡ Decoupling capacitors should be placed as close as possible to the component pins requiring stable voltage to ensure clean and stable power supply.
• 📦 Product enclosures must be designed with manufacturability in mind, considering the limitations and requirements of production methods like high-pressure injection molding.
• 🔌 Careful design of PCB landing patterns is necessary, especially when components are not included in standard libraries, to ensure compatibility with actual components.
• 🔗 Understanding the use of different types of PCB vias (through, blind, and buried) and their impact on manufacturability and cost is essential for efficient PCB design.
• ⚙️ Correct PCB layout for switching regulators is vital for their efficient operation, and following the layout guidelines provided in data sheets can prevent common mistakes.
• 🔄 The video emphasizes the importance of avoiding common design mistakes to streamline the development process and ensure the success of new electronic hardware products.

Q & A

What are the common design mistakes discussed in the video?

The video discusses 10 common design mistakes, including failing to design for manufacturing, incorrect design of wireless circuits, waiting too long to estimate manufacturing costs, insufficient width for high current PCB traces, not getting an independent design review, incorrect use of decoupling capacitors, designing the enclosure for manufacturability issues, incorrect PCB landing patterns, designing a PCB with manufacturing or cost issues related to vias, and incorrect PCB layout of switching regulators.

Why is it important to consider manufacturability during the product design process?

Considering manufacturability is essential because it can significantly affect the time and cost of bringing a product to market. A product that is difficult to manufacture can slow down production and increase costs, which can be detrimental to the product's success.

What is the significance of a transmission line in wireless circuit design?

A transmission line is crucial for the maximum power transfer between a transceiver and an antenna. It must be designed with the correct impedance to ensure efficient power transfer and optimal wireless functionality.

Why is it a mistake to wait until the final prototype to estimate manufacturing costs?

Waiting until the final prototype to estimate manufacturing costs can lead to unexpected expenses and redesigns, which can delay product development and increase costs. Estimating costs early allows for adjustments in the design to manage expenses more effectively.

What factors affect the width required for a high current PCB trace?

The required width of a PCB trace for high current is affected by factors such as the trace's thickness (copper weight), whether the trace is on an internal or external layer, and the permissible temperature rise for that trace.

Why is an independent design review important before prototyping a product?

An independent design review is important to identify and correct potential mistakes or oversights in the design. It can reduce the number of prototype iterations, save costs, and shorten the time to market.

How should decoupling capacitors be used in PCB design for optimal performance?

Decoupling capacitors should be placed as close as possible to the pin requiring a stable voltage source. The output capacitor for the power supply regulator should also be placed close to the regulator's output pin to ensure a clean and stable voltage supply.

What are the challenges associated with designing a product enclosure for high volume production?

High volume production, typically using high-pressure injection molding, requires adherence to strict design rules. Unlike 3D printing, which is forgiving, injection molding does not accommodate complex or intricate designs without significant modifications.

Why is it a mistake to manually draw PCB landing patterns without verifying against actual components?

Manually drawing PCB landing patterns without verification can lead to errors in pin-to-pin spacing, which can make it impossible to solder parts onto the board. It's essential to verify the landing patterns against actual components to ensure a proper fit.

What are the implications of using through vias, blind vias, and buried vias in PCB design?

Through vias connect all layers of a PCB, which can increase board size and reduce routing space. Blind and buried vias, while allowing for more compact designs, have strict layer connection rules and can significantly increase the cost of prototype boards. They should be used judiciously and only when necessary.

What are the key considerations for correctly laying out a switching regulator on a PCB?

For a switching regulator, the PCB layout must follow strict design rules to ensure efficiency and proper operation. Components should not be randomly placed but arranged according to the manufacturer's recommendations, which are typically provided in the data sheet.

Outlines

00:00

🛠️ Design for Manufacturability (DFM)

John Teal, founder of Predictable Designs, introduces the concept of Design for Manufacturability (DFM), emphasizing its importance in the development of electronic hardware products. He discusses the common mistake of underestimating manufacturing complexity and cost, which can be as significant as the product development itself. The video aims to educate viewers on avoiding this and other design pitfalls, regardless of their technical expertise. DFM is crucial for reducing time to market and ensuring efficient production, contrasting the outdated approach where engineers developed products without considering manufacturing feasibility.

05:02

📶 Wireless Circuit Design and Testability

The second paragraph delves into the intricacies of wireless circuit design, particularly the critical nature of proper PCB layout for RF components. John highlights the importance of impedance matching for maximum power transfer between the transceiver and the antenna, requiring a 50-ohm transmission line and often an LC matching circuit. He warns against the common error of improper design, which can reduce wireless functionality range. Additionally, he touches on the concept of Design for Testability (DFT), which involves creating products that can be easily tested during production, as a subset of DFM.

10:03

💰 Estimating Manufacturing Costs Early

In the third paragraph, John addresses the mistake of waiting too long to estimate manufacturing costs, which can lead to financial surprises and potential redesigns that delay product development. He argues against the misconception that accurate cost estimation must wait until the final prototype, asserting that with experience, costs can be estimated early in the design process. This proactive approach helps in making informed decisions about product development and can prevent costly iterations later on.

15:04

🔌 High Current PCB Traces and Design Reviews

This paragraph focuses on the technical aspect of ensuring sufficient width for high current PCB traces, which is critical for components drawing more than 500 milliamps. John explains how trace width depends on factors like copper weight and layer positioning, with external layers being more capable of handling current due to better heat dissipation. He also stresses the importance of independent design reviews to catch and correct errors before prototyping, which can save both time and money by reducing the number of necessary iterations.

🛡️ Decoupling Capacitors and Enclosure Design

The fifth paragraph discusses the proper use of decoupling capacitors to provide a stable voltage source for critical components. John explains the necessity of placing these capacitors close to the pin requiring stable voltage and the output capacitor near the regulator's output pin. He then transitions to the topic of product enclosure design, highlighting the difference between the forgiving nature of 3D printing for prototypes and the stringent rules of high-pressure injection molding for mass production.

🔄 PCB Landing Patterns and Component Verification

John discusses the common error of incorrect PCB landing patterns, especially when using components not included in standard libraries, which can lead to soldering issues. He suggests a practical method of printing the PCB layout at actual size and manually placing component samples to verify the accuracy of the landing patterns, ensuring that all pins align correctly with the components.

🔗 Via Selection and PCB Manufacturing Costs

This paragraph examines the impact of via selection on PCB design and manufacturing costs. John explains the differences between through vias, blind vias, and buried vias, and how their use can either be restrictive or costly. He advises against using blind and buried vias unless absolutely necessary due to their potential to increase prototype costs significantly, while also noting that these costs are less significant in high-volume production.

⚡️ PCB Layout for Switching Regulators

The seventh paragraph focuses on the complexities of designing the PCB layout for switching regulators, which are more efficient than linear regulators but require careful component placement and connection. John emphasizes the importance of adhering to strict layout rules and consulting data sheets for guidance on proper layout techniques.

🌟 Conclusion and Further Learning Opportunities

In the concluding paragraph, John summarizes the video's aim to help viewers avoid common design mistakes and encourages engagement through likes or comments. He introduces himself as John Teal from Predictable Designs and invites viewers to subscribe to the YouTube channel and visit the websites PredictableDesigns.com and TheHardwareAcademy.com for more insights on developing, manufacturing, and selling hardware products.

Keywords

💡Design for Manufacturing (DFM)

Design for Manufacturing (DFM) is a process where a product is designed with the manufacturing process in mind to ensure it can be efficiently produced. In the video, John Teal emphasizes the importance of DFM in reducing the time and cost associated with setting up manufacturing, highlighting that it should be a primary consideration throughout the product design process. The script mentions that failing to design for manufacturing can lead to significant delays and cost overruns, making it a critical concept in the video's theme of common design mistakes.

💡Manufacturability

Manufacturability refers to how easily a product can be produced using manufacturing processes. The video script underscores the significance of manufacturability as a key factor in the product development process. It is mentioned that the complexity of manufacturing is often underestimated, and that it can be as time-consuming and costly as the product development itself. The concept is central to the video's discussion on avoiding common design mistakes.

💡Wireless Circuits

Wireless circuits are components of a product that enable wireless functionality, such as Bluetooth or Wi-Fi. The script discusses the critical nature of properly designing the PCB layout for RF (radio frequency) portions of wireless circuits to ensure maximum power transfer and optimal performance. An incorrect design can lead to power loss and reduced operating range, making this keyword essential to understanding the video's focus on design precision.

💡Impedance Matching

Impedance matching is the process of ensuring that the impedance of a transmission line is compatible with the impedance of the load it is connected to, in order to maximize power transfer. The video script explains that for wireless functionality, the impedance between the transceiver and the antenna must be matched, usually at 50 ohms, to achieve maximum power transfer. This concept is crucial for understanding the video's discussion on the technical aspects of wireless circuit design.

💡LC Matching Circuit

An LC matching circuit is a simple circuit consisting of an inductor (L) and a capacitor (C) used to fine-tune impedance matching. In the script, it is mentioned as a necessary component for optimizing the impedance match between the antenna and the transceiver in wireless circuits. The correct use of LC matching circuits is highlighted as a common mistake to avoid in the design of wireless products.

💡Manufacturing Costs Estimation

Manufacturing costs estimation is the process of predicting how much it will cost to produce a product. The video emphasizes the importance of estimating these costs early in the development process to avoid financial surprises and the need for redesigns. It is noted that successful tech companies know the approximate manufacturing costs before beginning development, which is a key concept in the video's theme of avoiding common design mistakes.

💡PCB Trace Width

PCB trace width refers to the width of the conductive paths on a printed circuit board (PCB). The script explains that for traces carrying high current, the minimum width allowed may not be sufficient, and the required width depends on factors such as trace thickness and whether the trace is on an internal or external layer. This concept is essential for understanding the video's discussion on the technical aspects of PCB design.

💡Copper Weight

Copper weight is a measure of the thickness of the copper used in the conductive layers of a PCB, typically specified in ounces per square foot or converted to mils (thousandths of an inch). The video script discusses how the copper weight affects the current-carrying capability of a PCB trace and is an important factor in designing PCBs for high current applications.

💡Independent Design Review

An independent design review is a process where an external party or a group of peers evaluates a design to identify potential issues and suggest improvements. The video script stresses the importance of conducting an independent design review to reduce the number of prototype iterations and associated costs. It is presented as a best practice to avoid common design mistakes and ensure a more efficient development process.

💡Decoupling Capacitors

Decoupling capacitors are components placed on the power supply rail of a PCB to provide a stable voltage source to critical components. The video script explains that for these capacitors to be most effective, they must be placed as close as possible to the pin requiring the stable voltage. Incorrect use of decoupling capacitors is highlighted as a common mistake in PCB design.

💡Product Enclosure

A product enclosure refers to the outer casing of a product, which houses and protects the internal components. The video script discusses the importance of designing the enclosure to be manufacturable, especially when using high-pressure injection molding for high-volume production. The concept is tied to the video's theme of avoiding common design mistakes by considering manufacturing limitations in the design phase.

💡PCB Landing Patterns

PCB landing patterns are the physical layout on a PCB where components are placed and soldered. The video script warns against common mistakes made when manually drawing these patterns, such as incorrect pin-to-pin spacing, which can lead to components not fitting properly on the board. This concept is crucial for understanding the technical aspects of PCB design and the video's focus on avoiding errors.

💡Vias

Vias are conductive holes in a PCB that connect signals from different layers. The video script discusses different types of vias, such as through vias, blind vias, and buried vias, and the implications of their use on manufacturability and cost. The concept of vias is essential for understanding the video's discussion on PCB design and the trade-offs involved in choosing the right type for a given application.

💡Switching Regulators

Switching regulators are components that convert one supply voltage to another using energy storage elements like inductors and capacitors. The video script explains that while switching regulators are highly efficient, they are more complex to design correctly, especially in terms of PCB layout. Incorrect layout of switching regulators is highlighted as a common mistake, emphasizing the need to follow strict layout rules as outlined in the data sheets.

Highlights

Importance of designing for manufacturing (DFM) to avoid delays and costs in product development.

The old way of separating engineering and manufacturing leads to inefficiencies.

Design for testability (DFT) as a subset of DFM for easier product testing during production.

Critical aspects of wireless circuit design including impedance matching for maximum power transfer.

The necessity of using a 50-ohm transmission line and LC matching circuit in RF designs.

Estimating manufacturing costs early to prevent redesigns and budget overruns.

The impact of trace width on PCB designs, especially for high current applications.

The benefits of independent design reviews to minimize prototype iterations and costs.

Misuse of decoupling capacitors and their placement for optimal power supply stability.

Challenges in designing manufacturable product enclosures for high-volume production.

Common errors in PCB landing pattern design and the importance of verifying with physical components.

The role of vias in PCB design and the distinction between through, blind, and buried vias.

Cost implications of using blind and buried vias in prototype boards versus mass production.

Switching regulators' efficiency and the complexities of their PCB layout for optimal performance.

Guidance from data sheets on proper PCB layout for switching regulators.

The video's aim to help eliminate common design mistakes in electronic hardware development.

Encouragement to subscribe for more insights on hardware development, manufacturing, and selling.

Transcripts

there are design mistakes that i see

made over and over again on the

development of new electronic hardware

products so in this video you're going

to discover 10 of the more common design

mistakes that i see and this includes

both specific technical mistakes and

also more general mistakes so there

really is something here for everyone

regardless of your technical level hi

i'm john teal founder of predictable

designs okay let's get started so the

first design mistake that i want to

discuss is failing to design for

manufacturing

people always tend to underestimate the

complexity of developing a new physical

product and they even underestimate more

the complexity of actually manufacturing

it

for many products it takes nearly as

much time and sometimes even more to get

manufacturing set up and running

as it does to actually develop the

product

manufacturing setup can also cost as

much or more than all of your

development cost

so it's really essential that

manufacturability be a primary

consideration during the entire product

design process

and this process is called designed for

manufacturing or designed for

manufacturability or dfm for short

nothing will slow down your path to

market more than designing a product

that you find out can't actually be

efficiently manufactured

the old way of thinking was that

engineers would develop a product and

then they would just pass it on to

manufacturing and manufacturing would

have to actually figure out how to

actually produce the thing and there was

really no interaction between

engineering and manufacturing

but that's a horrible way to develop

products which is why all successful

companies have now abandoned this whole

process

it's much better to develop a product

with manufacturing in mind from the very

beginning

but also don't forget about something

known as design for testability which is

all about designing your products so

that it can be easily tested during

production and this can be kind of

considered a subset of design for

manufacturability the next design

mistake that i want to discuss is the

incorrect design of wireless circuits if

your product has any wireless

functionality then the pcb layout for

any rf portions is going to be super

critical

unfortunately it's done wrong more often

than it is done right so be sure you

watch this one very carefully so the

maximum power transfer between a

transceiver so this could be bluetooth

wi-fi something like that for the

maximum power transfer between that

transceiver and the antenna their

impedance must be matched this means two

things two things are required

first is a proper transmission line

connecting the antenna to the

transceiver

this transmission line is fabricated on

the pcb specifically for carrying

microwaves which are just high frequency

radio waves in most cases the

transmission line is going to need to be

designed with the 50 ohm impedance for

maximum power transfer with the antenna

be sure that you understand that it's

not the resistance of the feed line it's

the impedance the complex impedance it

has between the feed line and the ground

plane that's underneath of it in

addition to using a 50 ohm transmission

line it is also necessary to usually add

some type of lc matching circuit so an

lc is just a simple circuit that

consists of an inductor and a capacitor

so this circuit allows you to fine tune

the impedance so you can get it exactly

right and you can optimize the the

matching the impedance matching between

the antenna and the transceiver so you

get the maximum power transfer

if this matching is not done precisely

then you'll end up losing power

along your feed line and what this will

do is reduce the the operating range for

your wireless functionality so it's

definitely something that you want to

pay close attention to

the next design mistake that i want to

discuss and this one is more general and

less uh it's not a specific technical

mistake like the previous one that we

looked at and this mistake is waiting

too long to estimate the manufacturing

costs for your product successful tech

companies always know approximately how

much a product is going to cost to

manufacture well before they actually

begin developing it otherwise how can

they know the product is actually worth

developing

if you're not a billion dollar tech

company the odds are that you will first

get your product fully designed and then

once you have that final prototype and

you're ready to start manufacturing then

you will finally estimate how much the

product is going to cost to manufacture

but what happens though if you discover

that your product is going to cost more

to manufacture than you expected

you could increase your sales price

target but that obviously has negative

consequences

you could also make some redesigns to

lower the manufacturing costs but

wouldn't it have been

made more sense to just design it right

the first time for understandable

reasons many people think that you have

to fully develop a product before you

can accurately calculate the

manufacturing cost and that is

absolutely untrue

with the right experience it is possible

to accurately estimate the manufacturing

costs for just about any product and

this can happen well before any pcb

layout or 3d modeling occurs the next

design mistake that i want to discuss is

insufficient width for high current pcb

traces

if a pcb trace will have more than

roughly about 500 milliamps of current

flowing through it then in most cases

the minimum width allowed for a trace

probably won't be sufficient

the required width of a pcb trace

depends on several things including the

thickness of the trace which is also

specified as the copper weight

and whether the trace is on an internal

or an external layer so if you have a

four

layer printed circuit board there's two

outer layers or two external layers and

then two internal layers and that makes

a difference on how much current it can

carry

for the same thickness an external layer

can carry more current for the same

width than an internal trace because

external traces have better air flow

allowing them to better dissipate the

heat

the thickness depends on how much copper

is being used for that conducting layer

most pcb manufacturers allow you to

choose from various copper weights from

about

0.0.5 ounces per square foot so that

that's typically the unit is it's in

ounces per square foot so anywhere from

about a half an ounce per square foot up

to about two and a half ounces per

square foot

if preferred you can convert the copper

weight to a thickness measurement such

as mils

and typically when designing printed

circuit boards you're thinking in terms

of mills and if you don't know a mill is

just a thousandth of an inch

when calculating the current

carrying capability of a pcb trace you

must specify the permissible temperature

rise for that trace

now i want to look at a more general

design mistake that i see repeated over

and over and that is not getting an

independent design review done

if you don't get an independent design

review of your product before you

prototype it then you may literally be

throwing money away it doesn't matter

how good of an engineer you may be or

how good the engineer is that you've

outsourced your product design to

no one is perfect and all engineers make

mistakes

shocking i know i can't believe that we

make mistakes but we do

so

getting custom prototypes made whether

we're talking the pcb or the product's

enclosure isn't generally cheap and the

more prototype iterations that you

require the more it will cost in total

it will also take longer to develop and

bring the product to market

one of the best ways to reduce the

number of prototype iterations required

is to get a second opinion called a

design review

successful tech companies always require

their engineers to hold design reviews

to seek feedback from as many other

engineers as possible

now we're going to look at another

design mistake that's a specific

technical design mistake that i've seen

made commonly on printed circuit board

designs and that is the incorrect use of

decoupling capacitors

critical components need a clean stable

voltage source to operate properly and

decoupling capacitors are placed on the

power supply rail to help in this regard

however for the decoupling capacitors to

work their best they must be placed as

close as possible to the pin that's

requiring the stable voltage

also it's critical to place the output

capacitor for the power supply regulator

as close as possible to the output pin

of the regulator for the next design

mistake that we're going to look at

we're going to jump back to the product

enclosure and this mistake is designing

the enclosure for your product so that

it's not actually manufacturable

3d printing is extremely forgiving and

you can really design and print just

about anything your mind imagines

but 3d printing is only for producing a

few prototypes it's not for production

high pressure injection molding is the

technology used for producing plastic

parts in high volume

unfortunately injection molding is not

at all for giving it is a technology

with that requires a lot of design rules

that must be closely followed

these

from the very available

the next common design mistake that i'm

going to look at is incorrect pcb

landing patterns

all pcb design software tools include

libraries of components that are

commonly used these libraries include

both the schematic symbol as well as the

pcb landing pattern

all is usually good as long as you stick

with using the components in these

libraries assuming that they're correct

but from in most cases problems begin

when you

have to use components that are not

included in these libraries this means

the engineer has to manually draw the

schematic symbol and the pcb landing

pattern it's really quite easy to make

mistakes when drawing a landing pattern

for example if you get the pin to pin

spacing

off by just a fraction of a millimeter

then it will make it impossible to

solder the parts on the board because

all the pins won't line up with the

actual part there's a really handy trick

to to help prevent this and that is to

print out your pcb layout on at a

one-to-one scale so that it's exact same

scale as the the final printed circuit

board

then order samples of all the various

components mainly the microchips and the

connectors the more critical components

and then manually place those parts on

your printed out pc

pcb layout

this allows you to very quickly verify

that all the landing patterns are

correct and match the actual part the

next design mistake that i want to

discuss we're going to jump back to the

pcb design again and this mistake is

actually designed into print a circuit

board that either can't be manufactured

or is just exceptionally expensive to

manufacture

and these mistakes will commonly center

around

the types of vias used so a via is just

a conducting hole in a pcb that connects

signals from different layers so if you

have a signal on layer one and you want

to continue routing it on layer four

then you would just via have a via which

is a hole with the conducting material

in it so that the electrical signal can

go from layer one down to layer four

and the most common type of via is known

as a through via and the name through

via comes from the fact that it goes

through all the layers of the board

here you in this image you can see a

cross-sectional view that shows three

types of pcb vias

this one here that's labeled number one

is a through via this means that even if

you only want to connect a trace from

say layer 1 to layer 2

if you're using a through via then all

the layers will also have this via this

can actually increase the size of a

board since the v has reduced the

routing space on layers not even using

the via itself there are two solutions

to this problem if if reducing the size

of your board is of most importance then

you can look at two

types of vias called a blind via

which is like here you can see as shown

that's mark number two in this image

where it connects

layer one to layer two

then the other type of via is a buried

via which is shown as number three here

and a buried via actually connects two

internal layers the problem with blind

and very vias is they have very strict

limitations on which layers they can be

used to connect and it's all too easy to

use a blind or buried via in a way that

can't actually be manufactured or

prototype be warned though that even if

you use blind and buried vias correctly

they will drastically increase the cost

of your prototype boards

many times their use will in fact double

the cost of your prototype boards but

keep in mind this this board increase

will become a lot less significant once

you're you're producing high volume mass

produced boards but it's it's mainly

going to be a financial obstacle when it

comes to the cost to prototype your

board in almost all cases it's really

best to completely avoid the use of

buried and blind vias unless you

absolutely must squeeze every

square millimeter out of that board uh

typically they're not worth the

additional cost

for what little bit of space savings

that they're going to offer okay finally

the number 10 most common design mistake

that i see

is incorrect pcb layout of switching

regulators

so a switching regulator converts one

supply voltage to another by temporarily

storing energy and then releasing it in

the to the output in a controlled

fashion

the storage elements used are inductors

and capacitors for switching regulators

compared to a simple linear regulator

switching regulators are extremely

efficient and waste very little power

however they are much more complicated

to use correctly

one of the biggest complexities of using

switching regulators is correctly

designing their pcb layout you can't

just randomly lay down the components

and connect them up with the switching

regulator there are very strict layout

rules that you need to follow for laying

out a switching regulator correctly

fortunately nearly all data sheets for

switching regulators will include a

section in the data sheet that will show

you the proper way to do the layout and

we'll typically give you an example of

how to do the layout correctly hopefully

this video has helped you eliminate at

least some of the more common design

mistakes that i see made if you have

found it helpful please give me a like

or a comment below i would really

appreciate it i'm john teal with

predictable designs i hope you found

this video helpful and i hope you have a

great day hey there this is john teal

founder of predictable designs if you

enjoyed this video and you want to keep

learning more about developing

manufacturing and selling new hardware

products then be sure to subscribe to

our youtube channel and also check out

the websites predictabledesigns.com

and thehardwareacademy.com