#USB Zener diode

[rhic2cnel]

https://www.futureelectronics.com/p/electromechanical--circuit-protection--tvs-diodes/pesd1can-215-nexperia-6297154

USB Zener diode, Transient voltage suppression, Bidirectional TVS diode

PESD1CAN Series 70 V 17 pF SMT CAN Bus ESD Protection Diode - SOT-23

[bri2takerr]

https://www.futureelectronics.com/p/electromechanical--circuit-protection--tvs-diodes/sm6t36cay-stmicroelectronics-6152925

USB TVS diode, Bidirectional Zener diode, diode circuit, Diode arrays,

SM6T Series 600 W 36 V Bi Directional Transient Voltage Suppressor - DO-214AA

[brnrd2oss]

https://www.futureelectronics.com/p/electromechanical--circuit-protection--tvs-diodes/usblc6-4sc6-stmicroelectronics-7131158

USB TVS diode array, Transient voltage suppressors, ultra-high-speed interfaces

USBLC6 Series 4 Line 6 V Uni / Bi-Directional ESD Protection - SOT-23-6

[dnie2litth]

https://www.futureelectronics.com/p/electromechanical--circuit-protection--tvs-diodes/sm6t36cay-stmicroelectronics-6152925

Transient voltage suppressor, diode circuit, High voltage tvs diode

SM6T Series 600 W 36 V Bi Directional Transient Voltage Suppressor - DO-214AA

[mrioo2ress]

https://www.futureelectronics.com/p/electromechanical--circuit-protection--tvs-diodes/sm712-02htg-littelfuse-9049160

Transient voltage suppression diode, TVS diodes for USB, TVS diode application

SM712 Series 31 V 600 W Surface Mount Asymmetrical TVS Diode Array - SOT-23-3

[jnth2konn]

TVS diode array, TVS Zener diode, Electrical high voltage, Bidirectionnel TVS

SM6T Series 600 W 36 V Bi Directional Transient Voltage Suppressor - DO-214AA

[knnd2riman]

TVS zener diode, diodes, voltage surge suppresseur, Bidirectionnel TVS diode

SMBJ Series 600 W 32.7 V Bi Directional Transient Voltage Suppressor - DO-214AA

[ensts2see]

Voltage suppression, diodes, tvs diode application, tvs diode capacitance

SMCJ Series 30 V 1500 W SMT BI-directional Transient Voltage Suppressor

[jimn2ness]

High-voltage transients, tvs diode array, TVS zener diode, Bidirectional TVS

USBLC6 Series 4 Line 6 V Uni / Bi-Directional ESD Protection - SOT-23-6

[cry2baca]

https://www.futureelectronics.com/p/electromechanical--circuit-protection--tvs-diodes/pesd1can-215-nexperia-9227406

What Is a transient voltage suppression, usb protection circuit

PESD1CAN Series 70 V 17 pF SMT CAN Bus ESD Protection Diode - SOT-23

[andmaybegayer]

Business in the front, party in the back. Yes, I'm leaving the button like that. It's fine.

This is a Qualcomm Quickcharge Trigger, based loosely on this design, but only rigged for 12V.

When you press the button, it negotiates up from 5V to 12V from any QC 2.0 compatible charger.

Why? The 12V supply that runs my desk is a noisy, cheap pile of garbage that whines at 18kHz all the time, and my hearing is still good enough to hear that all goddamn night. Finding quiet 12V supplies that don't develop inscrutable hums a few months down the line is a crapshoot. On the other hand, cellphone chargers are usually impossibly quiet. I have a loose QC phone charger that I don't need for anything else, so if I can convince it to pump out 12V I can use that to run my desk. Hence, this pile of junk.

Tested and working, all I have to do is press the button to get it to put out 12V. Eventually I might get a 9V zener diode and an LED and set up an indicator that tells me if it's in 12V mode, but for now I'll lean on the fact that I built it and I know how it works.

This is NOT fully wired correctly, as in if you plug the USB cable in upside down it will not trigger correctly. Fixing this is not too hard but would require me to fuck around with the protoboard more than I already have and dealing with protoboard is miserable. I'll just put some alignment markers on the cable I'm using I guess.

I'll have to sit later with a hacksaw and cut this section of protoboard out. Bleh. Building a case for things like this is what makes me wish I had a 3D printer. The exposed pins on the bottom are a short risk so this will get a chunk of cardboard two-way taped to the bottom.

If you ever get a chance to stock up on industry standard barrel jacks, do it, I use these things everywhere.

Quickcharge is a dying protocol, being replaced almost wholly by USB-PD, but USB-PD requires putting an actual microcontroller in the mix whereas this can be done fully analogue, and I believe that even QC 3.0 is still simple enough that a human with some buttons and a few resistor ladders could query basically any voltage it can supply (which is many)

[adafruit]

yaaarrr! a Circuit Pyrate is ready to be your best mate on the hacking seas

⚓️🏴‍☠️🤖🔧💻🔗🐍🔋📚💡🔌✨🌐💬📌🔄🔍💼📊

we recently sold out of our stock of Bus Pirates https://github.com/BusPirate/Bus_Pirate and when we booked a reorder we found it's currently unavailable with no ETA for re-stocking. it made us think about revisiting this design, perhaps using an RP2040 instead: with native USB and CircuitPython and PIO it might be easier to add new protocols! we did do a "Circuit Pyrate" draft many years ago but it was based on the SAMD21 and we quickly ran out of space - another thing the RP2040 would excel at.

parsing data is something that Python does very well, and tannewt already has VT100 control code support for the REPL status bar, so we're having a go at re-implementing the UX in native python by instantiating a secondary 'data only' CDC UART endpoint https://learn.adafruit.com/customizing-usb-devices-in-circuitpython/circuitpy-midi-serial#usb-serial-console-repl-and-data-3096590 The default REPL can then be enabled or disabled with the onboard slide switch.

here's our draft that uses the same sizing and header location but of course all different parts. two challenges: the RP2040 is not 5V-tolerant like the PIC24J but it's also not guaranteed for high speeds, so we put a 1K+3.6V zener diode on the 4 GPIO pins that ought to let it work OK with 3 or 5V devices. secondly, the pin mux distribution for I2C and UART doesnt match the same as the original chip so we may have to PIO bitbang those interfaces. we're going to have to do a bunch of pin twiddling to find out the limitations of this design. we add a separate Stemma QT port, NeoPixel, and LEDs for both power outputs. fun fact, did you know that the bus pirate is CC-0 http://dangerousprototypes.com/docs/Bus_Pirate_v3.6#License a rarely seen license for OSHW!

our current pondering is how to best mimic the 5V tolerant inputs of the PIC24J - the 1K + 3.6V zener will definitely do the job but can slow down the IO quite a bit on those high speed SPI lines. because we want full bidirectional support for each pin and be able to enable/disable optional 10K pullups to 3V (internal) or 5V (external) we can't us the TXS0104 series: has built in un-disableable pullups. this app note has a few tips we're perusing https://ww1.microchip.com/downloads/en/DeviceDoc/chapter%208.pdf - #11 looks like it may work..any suggestions?

[innersuitbeard]

TVS Zener diodes

My study was about TVS Zener diodes, USB Diode array and Circuit Protection Devices, TVS Diodes, PESD1CAN,215, Nexperia.

[vsplusonline]

TP4056 1A Li-ion lithium Battery Charging Module Charging Board Charger TP 4056 - Mini USB

New Post has been published on https://apzweb.com/tp4056-1a-li-ion-lithium-battery-charging-module-charging-board-charger-tp-4056-mini-usb/

TP4056 1A Li-ion lithium Battery Charging Module Charging Board Charger TP 4056 - Mini USB

Price: (as of Jan 01,1970 00:00:00 UTC – Details)

TP4056 1A Li-ion lithium Battery Charging Module Charging Board Charger TP 4056 In the product image there are 2 similar items joint together, there will be only one item sold in this listing. Power: Medium Power Brand Name: TP4056 Usage: Zener Diode Structure: PNP Special Function: Common Point Contact Diode Frequency: High Frequency Type: Power Module Construction: Planar Type Material: Silicon Install Style: SMD Function: Power Triode Model Number: TP4056.

Onboard MINI USB head can directly link computer USB port charging The charging board can also be powered by pin (IN + and IN-) Reserved the TEMP pin header, and can be used as a lithium battery temperature detection PCB board size: 3.73 (cm) x1.5 (cm)/1.46”X0.59” Input voltage: 4V-8V maximum output charging current: 1000mA

[cdrsample-blog]

CDR Sample For Electrical Engineers

CDR Sample for Electrical EngineersIn Australia, there is an intense interest of the Electrical Engineers. The presumed organizations in Australia additionally respects the capable Electrical Engineer from different countries, where countless talented and qualified designers come to Australia consistently from various countries over the world to fill in. The Electrical Engineers from overseas with a wish to enhance their career in Australia are required to go through a CDR assessment by EA to get selected in the employment code: ANZSCO 233311. The engineers with four years of Bachelor’s degree in Electrical Engineering can apply for the post of Electrical Engineers. 

CDR sample for Electrical Engineers includes all the required reports such as Curriculum Vitae (CV), Continuing Professional Development (CPD), three Career Episodes (CE), and Summary Statement. The content of the CDR Report Samples is given below: CDR sample for Electrical Engineers includes all the required reports such as Curriculum Vitae (CV), Continuing Professional Development (CPD), three Career Episodes (CE), and Summary Statement. The content of the CDR Report Samples is given below: 

Curriculum Vitae (CV): Resume on the basis of a professional template.

Continuing Professional Development (CPD): The sample of CPD clarifies the Engineering Knowledge of the applicant – 470 words.

Electrical Engineer Career Episode Sample 1: “Battery charger system” – 2036 words

Electrical Engineer Career Episode Sample 2: “Transformer protection system” – 2076 words

Electrical Engineer Career Episode Sample 3: “Induction motor speed control system” – 1952 words

Electrical Engineer Summary Statement Sample: Detailed explanation of all the competency element – 2379 words. 

Electrical Engineering CDR Sample  

1 Project Name: Battery charger system 

This project was titled  “Battery charger system”. The engineering activities that the author did during the project are as below:

· To study and review the mechanics, feasibility, and factors to consider to design the charging system of lead-acid batteries.

· To select a component like a resistor, Zener diode, battery for the system development. 

· To develop the workflow mechanism and design the battery charger system

· To design the filter capacitor, bridge rectifier, and internal transformer

· To simulate the designed system using MULTISIM

·  To test and analyze the charging process of the developed system.

Problem & Solutions:

Some of the major problems that were encountered by the author during the “Battery charger system” along with their solutions are defined below:-

1.Problem 1 career episode 2 and its Solution

During analyzing the circuit charging module Arthur came across some problems regarding the charging module of the circuit. When the input was provided, the very high gain was obtained for the operational amplifier, and the operational amplifier produced the larger output. Due to the large output voltage,  the Zener diode connected to the output terminal of the operational amplifier was not functioning. This resulted in the fluctuation of the circuit.After study and research, Arthur found that there might be a problem regarding the connection between resistance capacity and an operational amplifier. Then Arthur checked the connection and found that there was no such issue regarding the resistance capacity and amplifier and circuit connection. The Arthur reviewed the limiting process of the output voltage of LM741 and found that using the register from the output of LM741 to the inverting terminal of LM741. Then the Arthur calculated the value of the negative feedback of the register and connected the register to the output of LM741 to the inverting terminal of LM741. Furthermore, the circuit performance found that there is a smaller output voltage of LM741 and gain was also decreased.

2. Problem 2 career episode 2 and its Solution

The output current and voltage was smaller than the actual voltage when AC to DC conversion took place. When the input signal was 230Vrms to AC-DC converter, the output was 12v, which was smaller than the actual voltage. So to take necessary steps, the Author studied the different research papers and found that the issue might have raised due to the element of AC to DC converter. During the analysis, Arthur found that the issue was raised due to the transformer. Secondary winding was bigger than the smaller winding, which caused less output voltage. To solve this the Arthur calculated the transformer ratio, which was 0.0073. Then, Author changed the primary winding of the transformer and found that the voltage from AC to DC converter was 16Vrms. The output of the AC to DC converter was given to the charging circuit.

3.  Problem 3 career episode 2 and its Solution

During the simulation, author faced a problem regarding the input voltage limit. Arthur found 40v output from the output of the voltage limiting circuit, which was greater than the expected output value.The Arthur found that the Zener diode value was greater than the expected value. When the output value of a more zen diode was greater than the actual value, the control transistor Q2 turned on the transistor Q1, the charging circuit disconnected from the input. Then Arthur changed the Zener diode value as per the calculation. When the output value of a more zen diode was greater than the actual value, the control transistor Q2 turned on the transistor Q1, the charging circuit disconnected from the input. Then |Arthur changed the Zener diode value as per the calculation and found that the voltage limiting value of the circuit was 15v. Electrical Engineering CDR Sample 2Project Name: TRANSFORMER PROTECTION SYSTEMThis project was titled as “TRANSFORMER PROTECTION SYSTEM”. The engineering activities that the author did during the project are as below:

•        To study and review the power system and protective method.

•        To select the component like microcontroller, relay and step down transformer based on the design of the system.

•        To design the hardware and software program for the system model.

•        To perform the connection of the components like relay, microcontroller and transformer for the development of the system.

•        To simulate the designed system in Visual basic 6.0 and Proteus software.

•        To test and analyze the performance of the overall circuit.

•        To perform the administration of the whole procurement process for the materials required in the project.

•        To inspect, monitor and supervise the activities on the site ensuring they were in accordance with the targeted budget, quality, environmental standards, and company regulations. 

Problem & Solutions:

Some of the major problems that was encountered by the author during the “Transformer protection system” along with their solutions are defined below:-

1.       Problem 1 career episode 2 and its SolutionInitially, the current sensor sensed the wrong value for the current that leads to isolating the transformer form power lines in normal condition. So to solve this issue, Arthur performed research regarding the issues and also consulted the project supervisor. From the research, the author found that the high-value resistor was for a current sensor, which increased voltage drop, and as a result, the power loss increased for the system. To solve this issue, a low and appropriate resistor for the circuit was used. Then again, the Author tested the voltage value from the current sensing device, but the issue was not solved. So Arthur further found that the accuracy of the sensor changed due to the use of the high-temperature coefficient resistor. So the Arthur mitigate this problem by using the resistor of low-temperature coefficient and by using low inductance resistor which solved the issue regarding the current sensor.2. Problem 2 career episode 2 and its SolutionArthur found a problem regarding the trip coil. The trip coil was not energizing as per the requirement of the system that caused the relay failure. To resolve this issue, Arthur found the mechanism of testing the failure of the relay so that damaged relay can be found. Using USB controlled tools, the Author found the damaged relay by measuring the resistance of the paths between different pins of the system. Then replaced the damaged relay with the new ones. When the fault occurred the relay operated and reclosed itself automatically when the fault cleared. Using this method problem regarding the relay was solved.3. Problem 3 career episode 2 and its SolutionLikewise, Arthur found that the relay encounters a mechanical problem, due to which there was poor protection. To solve the issue regarding the Relay, Arthur used TRIAC as a member of THYRISTOR family, which can be used for transformer protection. Due to the absence of the moving part, TRIAC will lead to less maintenance and a longer life span of the transformer. Due to the high load voltage in the transformer, the relay was facing the problem regarding sensing the abnormal condition to solve this issue, Arthur decreased the load voltage of the transformer. Electrical Engineering CDR Sample 

3 Project Name: INDUCTION MOTOR SPEED CONTROL SYSTEMThis project was titled as “INDUCTION MOTOR SPEED CONTROL SYSTEM”. 

The engineering activities that the author did during the project are as below

·        To study and review the speed control mechanism in the induction motor.

·        To select the component like multilevel inverter, induction motor, drives and switching device for the development of the system.

·        To design and develop the block diagram and workflow of the system model.

·        To design the control unit to control inverter and use AC supply for bridge rectifier.

·        To simulate the design system using MATLAB.

·        To test and analyze the performance of the system. 

Problem & Solutions

Some of the major problems that were encountered by the author during the “INDUCTION MOTOR SPEED CONTROL SYSTEM” along with their solutions are defined below:-

1.     Problem 1 career episode 3 and SolutionThe problem regarding the voltage fluctuation occurred when the load draws periodic variation in the current supply. So, the fluctuating current has developed the fluctuation in the supply voltage. This current has also caused a drop in the voltage of the system. The Arthur also found that the variation in the load has caused the voltage fluctuation in the system along with an issue regarding the harmonic in the AC Supply. To solve this problem, the Author added the small capacitor, so the reactive network power is strengthened and allowed the finer tuning requirements of reactive power. After adding the capacitor, the power factor was enhanced, and the reduction of voltage fluctuation was seen. This method also increased the active power and increased the stability and efficiency of the system.

2.     Problem 2 career episode 3 and SolutionRipples were seen in the system when the rectified signal was feed into the controlled multilevel inverter. To solve this issue, Arthur used the capacitor, but this resulted in the unexpected output of the system. This issue was raised because of the multilevel inverter or control unit. To solve these issues, a detailed study of the component was performed. Arthur found that during the rectification AC signal was converted into the DC signal, which was not pure because they contained ripples. So capacitor in the inverter was introduced, but the issue was not solved. After further research, the size of the capacitor also affect the DC Signal and produces ripples. So the size of the capacitor was increased as per the requirement of the system.

3.     Problem 2 career episode 3 and SolutionThere was an issue which was caused due to the series connection of the power devices which was made in order to handle the large voltage and power in the system. To solve this issue the device was integrated gate bipolar transistors, gate turns off thyristors and integrated gate commutated transistors. After this adjustment, there was a problem regarding the unequal dissemination of applied voltage across the series-connected device. Arthur found that due to less blocking voltage compared to the applied voltage that issue occurred. Arthur rechecked the model and datasheets of all switching devices and transistors and reconnected the component, and these solved the problem regarding the unequal dissemination of applied voltage.  

[terabitweb]

Original Post from Talos Security Author:

By Patrick Mullen.

We want to thank everyone who stopped by the Cisco Talos booth at DEFCON’s Blue Team Village earlier this month. We handed out these badges at our area where we had Snort rules challenges, reverse-Capture the Flag and recruiters ready to answer attendees’ career advice questions.

Unfortunately, there were two bugs in the board as created, which should be expected when it was created in such a short time, but we have a guide for how you can fix these. Once these bugs are fixed, you’ll have a fully functional Digispark clone that can be used for several projects, including impersonating a USB keyboard, as our example sketch does. You can also attach leads to the open jumpers to get full access to all of the pins from the ATtiny85 to drive your own projects.

Power is provided directly by the USB port when used as a USB device, by a USB charger, or via J2 at the top of the board. The center pin is GND, the right pin is for regulated for five volts, or the left pin can handle anywhere from 5V to 20V. During Defcon, we powered it with a nine-volt battery for convenience. The first bug is really easy — diode D1 on the lower right of the board has the line indicating the direction for the cathode on the wrong end due to using a faulty schematic.

The second bug took a bit more creativity to overcome, but the actual assembly isn’t too difficult and makes the build that much more fun. The issue is that the schematic for the USB port was rotated, so we need to tweak the circuit so everything connects to the right place. I think the end result adds character to the badge and is quite effective.

Tools needed:

Small straight slot (flat head) screwdriver

Soldering iron with a small tip

Solder

Small wire cutters

Small needle-nose pliers are helpful

Multimeter, or at least a continuity tester (beeps when two connections are attached)

A magnifying glass can be useful to check your work

Arduino IDE for programming the chip

Parts list:

ATtiny85 w/ Digispark bootloader. Bootloader is needed for programming over USB

8 pin DIP chip holder

5V power regulator

Through-hole mini USB connector

(2) 3.6V zener diodes

(1) Schottky diode

(2) 75 ohm resistors (or 100 ohm or 66.5 ohm as in schematic)

(1) 1.5k ohm resistor

(2) 330 ohm resistors

(2) LEDs

(1) 0.1 uF capacitor

(1) 4.7 uF capacitor

For reference, this is the board schematic. Note this schematic has the diode from USB 5V pin to the 5V rail upside down. The line indicating the cathode should be pointing up toward the 5V rail, not toward the USB port. But other than that, this is the best schematic I’ve found and is released under the creative commons license.

Prepare the board

To rewire the USB port in a way that is easier to build the board, we are going to have to cut one of the lines on the board.  If you want to be fancy, you can do this by drilling through the board, but scratching through the conductor (“line/wire”) with a straight slot screwdriver is more than sufficient.

Be careful to not hit one of the other lines and if you have a continuity tester (or a multimeter set on resistance and verify infinite resistance aka open connection), it’s always good to verify you’ve done so successfully and completely.

The line we want to cut (viewed from the back of the board) starts from the bottom-most connector of the USB jack, but cut it *after* the connection hole, before the ‘T’ junction.  See the photo since I’m not getting paid by the word and don’t want to write a thousand of them.  Note the multimeter is demonstrating there is no connection between the pin on the USB connector and that connection point on the board after our “cut.”

Prepare the USB connector

Thankfully, one of the USB connections is not used and this allows us to modify the jack to get rid of the unused pin and then create a bridge on the board to bring the pin that is used over to the circuit where it was originally supposed to be connected.

To remove the unused pin, flip the USB connector over so the pins are on top and the “open-end” is to the left. The pin you want to remove is the top left one.

I had great success by using the small straight slot screwdriver to bend the pin toward the “back” of the connector (to the right in the photo), then using needle-nose pliers to wiggle it back and forth until it broke off cleanly.

Solder on the USB connector

NOTE: We are going to need to bridge a connector here and to keep everything you need within the kit, we’re going to use part of a lead from one of the components.

Put the USB connector into the holes from the front side of the board and flip the board over.  You can use the power regulator (the black component with the metal fin) to keep the board level while you solder.

Solder the two positioning holes on the left to keep the connector from moving while soldering the pins.

Put one of the legs of the burnt orange / brown capacitor into the hole on the left with the pin sticking through it. Again, a picture helps here. All we are doing here is using a bit of that nice, thin wire from the capacitor to bridge between the two connectors on the left.

Solder all FOUR of the pins from the USB connector. DO NOT SOLDER THE EMPTY HOLE. These pins and these holes are really small.  Now would be a good time to clean your soldering tip and make sure you don’t use too much solder and bridge connections.

Cut the leg that you soldered into the hole about halfway up the leg. You don’t need much of the leg to go through the board when you solder the capacitor into the circuit, and you only need enough to reach to the open connection on the USB port.

Bend the cut leg over to the open connector, lay it across the connector being careful not to short any others, and solder it in place. Using your screwdriver can provide extra leverage and precision to bend the bridge all the way to the board.

Soldering on the “normal parts”

You can now solder on all components except the three diodes. The diodes are the “glass-looking” red things with the black line and the black with silver line component.

Notes for assembly — be aware that some parts are unidirectional.

The LEDs are unidirectional. The long leg goes through the hole with the square contact around it. NOTE: The two LEDs have square contact on opposite sides. 

The yellow capacitor is unidirectional. The long leg goes toward the “+” toward the bottom of the board. The burnt orange/brown capacitor can go in either way. The capacitors are connected in parallel, so it doesn’t matter which goes into the C1 or C2 connection.

R4 and R5, near the power regulator, are 330 ohms. In the kit, they are the fat resistors with orange-orange-brown stripes. Note the gold stripe on the resistors refer to the tolerance/”quality” of the resistor and doesn’t really matter for this circuit.

R3 and R1, the top two resistors below the USB connector, are 75 ohms, with purple-green-black stripes. If your kit does not include these resistors (we bought every 75 ohm resistor at Fry’s in Las Vegas), 100 ohms is a common size that will also work.  

R2, the bottom resistor on the right side, is 1.5k ohms and has brown-green-red stripes. 

The big blue resistors in the kits are not used. They were supposed to be 66.5 ohms. They are 66.5 *thousand* ohms. Oops.

The chip connector has a notch on it that lines up with the break in the silkscreen to the right.  This is used to indicate pin 1 on the chip. Do not have the chip in the socket while soldering it in place. Do not forget to trim the ends of the leads off after soldering.

The power regulator (the black thing with the metal fin) has a line on the board on the left side that indicates where the cooling fin goes. When connecting this component, I find that leaning it to the right when soldering it on will give you a little extra room to bend it over to the left so it’ll lie flat when finished.

Soldering on “funky bits”

Now, we need to reverse the 5V and GND circuits. I think steps 1 and 2 below make more sense if you see what the circuit will look like before reading it, so this is what you should have after step 2:

Take one of the zener diodes (the little glass-looking things with the red underneath and the black stripe).  The black stripe lines up with the stripe on the circuit board printing.  But, because this is the “funky” section, we’re going to connect it “weird.”

Insert the zener diode into the *left* diode slot, U3, but stick it in so it points straight up, with the black line down against the board.

Solder it in the straight-up position.

When you cut the lead on the back of the board, SAVE THE CLIPPING.  We’ll need it in a moment.

Leave the diode in this position for now.

Take the other zener diode, and bend the end with the black stripe as if you were going to mount it normally, but leave the other leg straight.

Insert it into the top connector of U2 (so the stripes match) but angle it to the left so it crosses the U3 silk screening before you solder it on.

You may find that with the other components on the board, and the relative sizes of the wire and the hole, that it’s easier to solder this component from the top if you leave yourself room after the bend.  Cut off the extra in the back of the board and solder from the back for a good connection if necessary.

Bend the loose leg of U2 so it goes around the bottom hole of U3 and across the top of the chip holder.  This is easier with needle-nose pliers.  We will be soldering this leg to the bottom leg of U3, so don’t worry about keeping a distance from the wire.

Connect the zener diodes together

Returning to U3 (the zener diode on the left), bend the remaining wire forward, through the bottom hole for the diode, and solder it into place.  Using needle-nose pliers to make the bend and insertion may make it easier.  Be gentle so you don’t snap the diode in half.  There’s no reason to get this too tight and risk breaking the component.

Solder the bottom leg of U2 to the bent leg of U3. Don’t forget to make sure that U3 is soldered into the board as described in the previous step.

Connect the zener diodes to GND

Solder the leg you removed from U3 into the top connector for D1, with the leg sticking straight up out of the board.  We are going to bend it so we can connect it to the tail of U2 (which has been bent around the bottom wire from U3).

Bend the leg up to meet the long lower leg from U2 and solder them together.  You should now have a connection from the top of D1 to both diodes, at the bottom of U3.

Solder the schottky (black w/ silver stripe) diode

For this one, the silkscreen is backward because the schematic I was using had this diode backward, so ignore the marking on the board. We are using the long legs of this diode to make a long connection to fix the circuit without needing additional wire. With the fix, the proper connection is for the end with the silver stripe to connect to the bottom of D1 and the other end to connect to the bottom of U2.  Feel free to tuck this in as much as you can, but make sure you are clear of any wires touching.  If you’re feeling particularly frisky, you can use the diode itself as an insulator against the connector for U2 that goes around the chip carrier, or some electrical tape.

Insert the chip

There is a little dot on top that indicates pin 1. That goes toward the end of the chip carrier with the indent (to the right of the board).

This is what the completed circuit should look like:

Programming the board

I’m going to outsource the programming of the board now to this YouTube tutorial. Remember, this board uses the ATtiny85 chip and is a Digispark clone. If you have any issues, search for those names online and you should get what you need.

Everywhere the creator of this video says “Digispark board,” hear “Talos Defcon 27 Blue Team Village badge” because they are the same.

Open the Arduino IDE and load the Digispark board managers (1:48 in the video).

Load the drivers (3:54 in the video).  Hopefully, with our board and the bootloader we have installed, this step will be easier for you.  He provides information and links if you have troubles.

Load the Arduino IDE (7:24 in the video).  If you want to do the blink sketch he talks about, you’re welcome to do so.  Or just go right to the excitement and do the next step instead!

Copy and paste this sketch

Now you can upload the program. Don’t forget to unplug the badge (if necessary) and plug it in when the IDE tells you to (as described at 9:07 in the video).

Now that your badge is programmed, you no longer need the Arduino IDE or drivers to control other computers. Just plug it in, wait five seconds while the board initially identifies itself as an Arduino then disconnects and reconnects as a keyboard, and watch it do its thing.  LED1 is a status light as programmed in the sketch — it turns on when it starts typing and turns off when it’s completed all of its commands.

If you want your badge to send different commands, change the lines that call the function type() and tell it to type something else. Please note that these chips have extremely tiny memories and unfortunately the DigiSpark library takes up a lot of room so you don’t have a ton of text you can type, but you do have a fair amount. If you look into trimming the installed size of the code you should be able to get more program onto the chip.

Some other notes on the badge:

If you get female lead connectors and solder them to J1 and J2, you can use the ATtiny85 to do whatever you want, as long as you only need a few data lines and a small memory.  You can, of course, solder to the leads directly if you want, but by putting in female leads you can make a reusable circuit.  Note it is probably not a good idea to drive the data pins however you want while connected to a USB data cord.

J2 is for external power, so you can run the board while not connected to USB.  The middle connector is ground.  The connector on the right is for 5V *only*.  The connector on the left can run 5V-20V DC.

You can also power the circuit using a USB charging cable, but as stated above, it’s not recommended to be connected to the computer USB data port if you’re running a sketch that is not specifically for driving USB data, like a keyboard.

You can program it either through the USB as you did above or by using something like an Arduino UNO as an ISP as described in this video.

If you want to change the bootloader (or if you get a stock ATtiny85 that doesn’t have the boot loader we installed on the ones in the kit), directions are in this video.

We hope to continue and do other badges in the future, hopefully, next time without bugs! We hope everyone had a great time at Hacker Summer Camp and look forward to next year where we’ll have all new challenges, badges and other fun things to poke at.

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Go to Source Author: Talos DEFCON badge build instructions and use Original Post from Talos Security Author: By Patrick Mullen. We want to thank everyone who stopped by the Cisco Talos booth at DEFCON's Blue Team Village earlier this month.