USB key activated by monostable multivibrator - Schematic and PCB layout

For encrypting some online transactions, I am using a PC connected USB key. A transaction never takes more than a minute or so, and for security reasons, this USB key then needs to be removed once transaction completed, or hackers could perform transactions if they have control over my PC, especially when I am not in front of the PC.

That continuous having to plug and unplug the USB key is bothering me, and I would like to make a small box in which this USB key is plugged in. It has a button, and when pressed on this button, the USB key (data bus) will be activated for approx. 2 minutes, and then automatically disable the USB data bus again. So the only thing I need to do just before performing the transaction, is single press the button, and forget about it.

As I lack the time to build it myself, I am looking for a freelancer who can design the schematic and PCB layout. Both schematic and layout MUST be natively drawn in ALTIUM or CIRCUITSTUDIO, and please advise both application and version you will be using while bidding. Converted files from other packages will not be accepted. Simulation could also be performed with LTSpice.

Functional description: A monostable multivibrator, build with MC74VHC1G132 (SOT353) smith trigger NAND gate (as I have those in stock), will be triggered by a single press of a button, this will activate a 2x2 USB SWITCH (a FSUSB30MUX, also already in stock). The state should remain active for a good 2 minutes, the time needed to approve an online transaction. All this will be powered from USB, which will be hard-wired to the device and permanently connected to my PC. Being able to provide a simulation model of the monostable multivibrator section would be a plus.

I assume you have sufficient knowledge to connect and select/add the remaining components to make it to a working schematic. I would like to review and approve schematic and simulation model prior to start of layout.

This is not an urgent project, but I care about good craftsmanship and attention to (functional) detail. Un-careful component placement or sloppy routing will be returned to sender…

MC74VHC1G132 => [login to view URL]

FSUSB30MUX => [login to view URL]

Evner: Elektronik, Elektrisk Ingeniørarbejde, PCB Design and Layout, Schematics

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Om arbejdsgiveren:
( 9 bedømmelser ) Taichung, Taiwan

Projekt ID: #32220325

Tildelt til:


Greetings, I am honoured to get this opportunity of being able to assist you. I have gone through your project brief and attached files as well which made everything clear regarding your project. I am an electronics Flere

$50 USD in 2 dage
(12 bedømmelser)

17 freelancere byder i gennemsnit $279 timen for dette job


Hi, I have almost 15 years of experience. I have read the details and have a few questions. Please get back to me to discuss it further. Thanks

$200 USD in 4 dage
(249 bedømmelser)

Best USB Design Expert at your doorstep! Dear Client, We can design schematic and layout PCB with "small USB Key box" using button in Altium for activated by monostable multivibrator. We have seen the attached docume Flere

$180 USD in 2 dage
(43 bedømmelser)
(148 bedømmelser)
(30 bedømmelser)

Dear Valued Employer, My name is Martin and I am an engineering physicist with extensive experience in the field of circuit design, circuit prototyping and PCB design. As I understand from the project description you Flere

$200 USD in 42 dage
(15 bedømmelser)
(47 bedømmelser)

Hello, client. I use Altium Designer 21.7.2. I hope to work with you because your project is very familiar to my past works. [login to view URL] I have 9+ Flere

$200 USD in 2 dage
(14 bedømmelser)

Hello, I am an electronics and telecommunication engineer and my major is wireless systems' design. I am experienced in hardware and embedded systems' design. I have designed/printed/tested many PCBs and I am quite exp Flere

$200 USD in 7 dage
(36 bedømmelser)

I have more than 9 years experience in embedded hardware design with eagle and altium design software with lt spice simulation also . So I can do your job within a time limit with your satisfaction.

$1390 USD in 15 dage
(7 bedømmelser)

hello sir, how are you. I read your proposal and i am interested in this project. I am an Embedded engineer (ARM, PIC, AVR, Arduino, SOC BLE (bluetooth) chips, ZigBee, WiFi, GPS, LED, LCD display etc.) and PCB designer Flere

$150 USD in 7 dage
(18 bedømmelser)

Hi I can design schematic and layout PCB with "small USB Key box" using button in Altium for activated by monostable multivibrator in a quality and timely manner. I have humungous experience in USB Key Based PCB des Flere

$140 USD in 2 dage
(2 bedømmelser)

Hi there, i have thoroughly gone through your project description, i am very much interested in working on your project because i'm an experts in this. I'm a senior engineer with rich experience in Electronics, Elect Flere

$200 USD in 5 dage
(7 bedømmelser)
(5 bedømmelser)

Hello. I have read your project description and i like the project USB key activated by monostable multivibrator - Schematic and PCB layout i'm an expert in arduino and expert in PCB layout in altium software up to 4 Flere

$250 USD in 7 dage
(11 bedømmelser)
(2 bedømmelser)

1 ) I have over 20 years of experience in PCB Layout, HW, RF, EMI, FW designs. we can complete various design and layout requirements and Android / iOS app development. # 8051 MCU / ARM Embedded system / Arduino / Flere

$250 USD in 7 dage
(2 bedømmelser)