Introduction: HackerBoxes 0018: Circuit Circus

Picture of HackerBoxes 0018: Circuit Circus

Circuit Circus: This month, HackerBox Hackers are working with analog electronic circuits as well as techniques for circuit test and measurement.

This Instructable contains information for working with HackerBoxes #0018. If you would like to receive a box like this right to your mailbox each month, now is the time to subscribe at and join the revolution!

Topics and Learning Objectives for this HackerBox:

  • Build a microprocessor-based component test device
  • Hone PCB assembly and soldering skills
  • Understand the use of various electronic components in circuits
  • Review test and measurement techniques for those components
  • Complete a ten lesson Modern Electronics course
  • Complete a ten lesson Analog Electronics course
  • Explore applications and limitations of sound card oscilloscopes
  • Exercise techniques to prototype circuits on breadboard

HackerBoxes is the monthly subscription box service for DIY electronics and computer technology. We are hobbyists, makers, and experimenters. And we are the dreamers of dreams.

Step 1: HackerBoxes 0018: Box Contents

Picture of HackerBoxes 0018: Box Contents
  • HackerBoxes #0018 Collectable Reference Card
  • Electronic Component Test Device (Solder Kit)
  • Modern and Analog Electronics Kit
  • 140 Piece Wire Jumper Kit
  • 830 Point Solderless Breadboard
  • 3.5mm Audio Breakout Module
  • 3.5mm Audio Patch Cable
  • Two 9V Battery Clips
  • Exclusive "Elite Technology" Iron-On Patch
  • Exclusive HackerBoxes Quad Decal

Some other things that will be helpful:

  • Soldering iron, solder, and basic soldering tools
  • Two 9V Batteries
  • Computer with Sound Card
  • (optional) USB Sound Card **
  • (optional) Digital Multimeter

Most importantly, you will need a sense of adventure, DIY spirit, and hacker curiosity. Hardcore DIY electronics is not the easiest hobby, but when you persist and enjoy the adventure, a great deal of satisfaction may be derived from persevering and getting your projects working. Just take each step slowly, mind the details, and don't hesitate to ask for help.

** Sound Card Note: Step 11 discusses optionally using a USB Sound Card.There happened to be a number of these on hand as surplus at HackerBoxes HQ. We threw them in FOR FREE as a bonus gift in a limited number of RANDOM #0018 HackerBoxes. If you did not receive one, please note again that they were randomly given out freely (without impacting the budget for the box). They are not included on the contents list above and therefore cannot be considered a "missing item". If you would really like one, they are available for purchase here. Thank you for understanding.

Step 2: Automata, Penguins, and Clowns

Picture of Automata, Penguins, and Clowns

The Exclusive HackerBoxes Quad Decal is designed to be separated into four miniature decals each perfectly sized for project enclosures, mobile devices, laptops, or toolboxes.

The Glider Symbol is featured on one of the miniature decals. It is a pattern of five dots arranged within a grid. That specific pattern travels across the board in Conway's Game of Life (a well known cellular automaton). The glider has been proposed as an emblem to represent the hacker subculture, since the Game of Life appeals to hackers and the concept of the glider was born at almost the same time as the Internet and Unix. The Wikipedia entry explains that this emblem is in use in various places within the subculture but it is not universally liked. If you do not like it, hack it. Either way, we suggest that you get a "Conway's Game of Life" program or app and play around with it. ALife!

What's up with the clown? The clown fan art and the "Circuit Circus" theme are allusions to the iconic Circus Circus Hotel and Casino in Las Vegas. Perhaps we will see you in Las Vegas this summer for DEFCON25?

Step 3: Modern and Analog Electronics Kit

Picture of Modern and Analog Electronics Kit

The HackerBoxes Modern and Analog Electronics Kit contains over 80 electronics components. Many of these can be useful while experimenting with the Electronic Component Test Device.

These components along with other contents of HackerBox #0018 comprise everything needed to perform all of the experiments in the Modern Electronics and Analog Electronics online courses presented later in this Instructable.

Step 4: Electronic Component Test Device - Introduction

Picture of Electronic Component Test Device - Introduction

We all know the annoying challenge to identify the exact parameters of a component in the old junk box. Conventional approaches of identification and measurement are generally difficult and time-consuming. This test device is here to save the day using a very clever microcontroller-based design. Best of all, it is supplied in kit form so you get to build it yourself!

Once completed, we will automatically detect and identify pinouts for NPN and PNP transistors, FETs, diodes, dual diodes, thyristors, and SCRs.

Resistances up to 50MΩ can be measured with a maximum resolution of 0.01Ω. Three test points allow simple testing of potentiometers.

Capacitance of 25pF-100mF can be measured with a resolution of 1pF. Equivalent series resistance (ESR) is measured for capacitors over 90nF.

Bipolar Junction Transistor measurements include the collector-emitter current amplification factor, the base - emitter threshold voltage, the collector-emitter leakage current, the base-emitter threshold voltage, and the high current gain. Darlington transistors are identified. Protection diodes for power transistors and FETs are detected.

FET parameters measurements include gate-source threshold voltage, drain-source resistance, and gate-source capacitance.

Additional features:

Frequency measurement 1Hz-1MHz

Period measurement up to 25kHz

DC voltage measurement up to 50V

Square wave frequency generator at various frequencies

10bit PWM generator (1% - 99%)

Digital Thermometer (DS1820) Reader

Temperature / Humidity (DHT11) Reader

IR Sensor Protocol Decoder (uPD6121 and TC9012)

IR Encoder


Processor: Socketed ATMEAG328P (28 pin DIP)

Color Display: TFT with 160x128 pixels and 16-bit color depth

User Input: Rotary Encoder with Pushbutton

Input Power: 6.8-12VDC at Barrel Connector OR 9V Battery

Current Consumption: Approximately 30mA

Step 5: Electronic Component Test Device - Bill of Materials

Picture of Electronic Component Test Device - Bill of Materials

Start building the kit by unbagging the components into a small tray and carefully familiarizing yourself with each component.

There are 24 axial-lead resistors having 12 different values. They all look very similar. We suggest taking a few minutes right now to look up and carefully note their values onto the paper tape attached to the resistors. The resistors are not interchangeable. If each resistor is not placed into its proper location on the PCB, the test device will not function.

This resistor code calculator is very handy. Be sure to switch to the "5 stripe" tab. Some "process of elimination" might be necessary when two sets of color stripes look very similar.

Step 6: Electronic Component Test Device - Transient Voltage Suppression

Picture of Electronic Component Test Device - Transient Voltage Suppression

The component tester kit includes three tiny surface mount components - an 0805-sized 100nF capacitor, an 1812-sized P6KE6V8 Diode, and a SOT23-sized SVR05-4 diode array. These are completely optional components to support Transient Voltage Suppression (TVS). The tester will work fine without them, so unless you have a microscope and SMT experience, we strongly suggest you start by throwing these components away.


The purpose of the TVS protection circuit is to improve the likelihood that the microcontroller input pins might survive discharge current when a charged capacitor is connected to the test inputs. Even with the TVS circuit installed, protection is not guaranteed. Therefore it is very important that capacitors always be discharged before measuring with the competent test device.


The three SMT components should be soldering first. The capacitor and the single diode are not polarized and may be soldered in either direction. The 6-pin diode array however has a polarity markings that should be aligned with the makings on the PCB silkscreen.

Step 7: Electronic Component Test Device - Small Components

Picture of Electronic Component Test Device - Small Components

Start by soldering in the 24 resistors. Make sure they have been correctly identified by their color bands. Be very careful to place the correct values in the correct positions on the PCB. Resistors are not polarized and may be inserted in either direction.

After a through-hole component is soldered, the lead should be carefully clipped from the rear very close to the PCB surface. Always wear safety glasses when snipping wire leads.

Next insert the 9 ceramic capacitors being sure to match the values printed on the capacitors to the PCB markings. These capacitors are not polarized and may be inserted in either direction.

The two electrolytic capacitors look like black barrels. They are the same value, but their leads are polarized. One side of the cap has white stripe. This is the negative side. The other lead is the positive side and should be aligned with the "+" marking on the PCB.

The Red LED is polarized. The longer wire lead should be inserted into the square metal pad hole.

The five TO-92 devices are semicircular in cross-section. Match the orientation of this shape up with the outline marked on the PCB. Note that there are four completely different types of devices in TO-92 packages, so be sure to match the numbers printed on the packages with the designations on the PCB.

Finally, the 8MHz Crystal is not polarized.

Step 8: Electronic Component Test Device - Larger Components

Picture of Electronic Component Test Device - Larger Components

Next insert and solder the larger components. These are fairly self-explanatory, but here are some pointers:

The three blue screw terminals should each be oriented so that the side ports face the edge of the PCB for inserting leads.

The arm of the ZIF (zero insertion force) socket should be left in the UP position while soldering.

The DIP28 socket should be soldered in without the chip inserted. Align the half-circle marking on the PCB to similar shaped formed into one edge of the socket. Once the soldering cools on the socket, the chip can be inserted according to the same semi-circular pin-one marking.

The 8pin display socket gets soldered to the main PCB. The 8pin male header is soldered to the backside of the TFT display for mating with the socket.

Two brass standoffs and four bolts are used to stabilize the display module once it is inserted.

Four brass standoffs and four bolts are used to form feet on the rear of the main PCB. These feet prevent the trimmed leads of the soldered components from scratching the desktop, as they can be quite sharp.

The 9V battery clip leads are soldered into the holes labeled 9V at the left side of the PCB. The red lead goes into the "+" terminal.

Step 9: Using the Electronic Component Test Device

Picture of Using the Electronic Component Test Device

Once power is applied to the Component Test Device, it can be powered up by pressing the rotary encoder down (there is a push-button integrated into the encoder). There is a calibration process than can be performed by shorting the three test points together. You can optionally skip the calibration for now and jump right into trying out some components to test in the next step.

A highly detailed document entitled TransistorTester with AVR microcontroller and a little more is frequently updated and available online. This document covers the design, use, and theory of operation for the various incarnations of these instruments. Definitely check it out.

This page has a whole variety of related resources in different languages.

Step 10: Ten Lesson Online "Modern Electronics" Course

Picture of Ten Lesson Online "Modern Electronics" Course

Everything you will need for the PyroElectro Modern Electronics online video course is included in the HackerBox Modern and Analog Electronics Kit.

While exploring the lessons on resistors, capacitors, inductors, diodes, and transistors, take a second to test the component under investigation using the Electronic Component Test Device.

Once you learn more about how each component functions in a circuit, you might want to go to the big document for the Electronic Component Test Device and review the theory of operation to discover how the tester is able to interrogate the device under test using a simple AVR microcontroller. Many of the techniques are very clever and demonstrate useful approaches for your future design or test work.

Lesson 9 on the 555 Timer is a great opportunity to play with the frequency measurement function of the Electronic Component Test Device.

Much respect for the work done by PyroElectro on these lessons.

Step 11: Ten Lesson Online "Analog Electronics" Course

Picture of Ten Lesson Online "Analog Electronics" Course

Everything you will need for the PyroElectro Analog Electronics online video course is included in the HackerBox Modern and Analog Electronics Kit.

Note that the 3.5mm audio patch cable can be cut in half to create two sets of "probes" for use with the Sound Card Oscilloscope discussed in this course. The stripped wire leads should be tinned with solder for easy manipulation without fraying.

While the exact circuits shown in the course are presumed to be safe, it is worth noting that the sound card inputs on your computer are only designed to handle a range of around -0.8V to +0.8V. When dealing with larger voltage ranges, the signal will need to be scaled down as to not overload the sound card inputs. Here are some excellent notes from Make and also from Daqarta.

If you plan to experiment broadly with sound card oscilloscopes and want to have some extra insurance against damaging your sound card, you might want to pick up an inexpensive USB Sound Card for some added electrical isolation.

The particular oscilloscope software suggested in the course is specifically for use with Windows. For Linux, there is a similar program called xoscope. For OSX users, there are various notes online about using Audacity as a sound card oscilloscope. For those who work with MATLAB or GNU Octave, look into the audiorecorder() function!

Much respect for the work done by PyroElectro on these lessons.

Step 12: Hack the Planet

Picture of Hack the Planet

Thank you for joining our adventures into modern analog electronics test and measurement. If you have enjoyed this Instrucable and would like to have a box of electronics projects like this delivered right to your mailbox each month, please join us by SUBSCRIBING HERE.

Reach out and share your success in the comments below and/or on the HackerBoxes Facebook page. Certainly let us know if you have any questions or need some help with anything. Thank you for being part of HackerBoxes. Please keep your suggestions and feedback coming. HackerBoxes are YOUR boxes. Let's make something great!


MikeM515 made it! (author)2017-10-24

This was pretty fun to make! I am learning to use a 3D printer I bought and made a case for it that I found on Thingiverse (

jumson made it! (author)2017-09-14

I enjoyed this so much I made Instructables about it! One for how to Assemble it, and another showing some Testing:



kaigoth made it! (author)2017-08-20

Enjoyed this kit, thanks HB!

Jbrid867 (author)2017-06-22

Hey so i just finished mine and having some strange, probably assembly based behavior. The screen illuminates but no text appears except, *sometimes*, it begins flashing "Short probes!"... Im able to get there kind of by randomly playing with the function menu (at least, I think thats how I get there). I short them, it keeps flashing "short probes" for a while then gives me the Hi/Lo resistance, then displays C0, then shuts off.

Any advice would be helpful, even if it's just "you might need to start over".

Jbrid867 (author)Jbrid8672017-06-22

It seems my button pressing probably wasnt doing anything. It shows me battery info if I wait long enough then switches to the short probes calibration step

GavinW38 (author)Jbrid8672017-07-01

Have you figured out the issue? mine does the samething and now it is just showing 1-3 >100nF

Jbrid867 (author)Jbrid8672017-06-26

anybody wanna chime in? otherwise imma consider it and myself a failure

Jbrid867 (author)Jbrid8672017-06-23

also it says hi and lo but Ri_Hi=~120 and Ri_Lo=~2k, so I'm not sure what it means and cant find it in the docs.

Other strange behavior: After turning on, sometimes it doesn't go to calibration. The LED turns off as well as the screen, momentarily, before the backlight comes back on.

I attached some images if that helps

BobM16 (author)2017-06-30

Completed mine, but I think perhaps the micro may be faulty. On initial power-up it waits until I depress the encoder to start, but then never responds to a depression of the encoder. Can move through the menu after it times out after the first measurement, but cannot select any of the menu items. I do see that the encoder push button is not shorted, as the LED blanks each time the encoder is depressed. What did I screw up?

RichW36 (author)2017-06-22

I have a problem with the audio cable included in the kit. The wires are so small and I am having a hard time knowing which is the insulation and which is the wire. I dont think that this wire was intended for what we are using it for and the one that is in the instruction video looks like it would be much easier to use. I would like to buy a cable already done that way i could get down to finishing the courses.

HackerBoxes (author)RichW362017-06-22

Tinning the thin wire with solder can build it up so that it is easier to work with.

Note that you can also use a "3.5mm Audio Breakout Module" and an uncut 3.5mm cable to "breakout" the audio cable pins onto a solderless breadboard. It requires more parts, but it is certainly "easier".

bitanalyst made it! (author)2017-06-10

I had a lot of fun putting the component tester together. I managed to solder the surface mount components with a pair of tweezers and some flux.

My tester seems to always want to run the calibration process when I power it on. I haven't figured out how to stop that from happening yet. I also have a hard time getting to the menu. Interesting device though!

barduinor made it! (author)2017-05-01

Cool build.

Anyone sharing a box for 3d print?

marchah (author)barduinor2017-05-28

dr0mi0 made it! (author)2017-05-28

Not really a case, but a simple base to use with the transistor tester with a minimalistic approach, allowing easy handling and keeping all electronics exposed to view.

AnandS80 made it! (author)2017-05-20

My First Soldering Kit and i had lot of fun.

park_ind_ent made it! (author)2017-04-30

Transistor Tester kit complete and now on to making a case for it. First version on the printer.

tbrannam (author)park_ind_ent2017-05-15

Care to post the file?

park_ind_ent (author)tbrannam2017-05-15

You can find it on thingiverse at:

kshowell (author)park_ind_ent2017-05-02

Nice :)

TimGTech (author)park_ind_ent2017-05-01

That pretty sweet.

rob_hunt (author)2017-05-06

I used to work on an SMT assembly line, so I figured I'd try assembling the component tester with the surface mount parts.. I soldered everything up, cleaned the board, plugged in the battery and... .nothing. Completely dead. Turns out if you put the diode network on backwards the board won't work. At all. It also turns out that it's really really hard to read the markings on that part if you get any flux on it. So... I re-cleaned the board and found my error. I had to remove one of the screw terminals so I could get to the diode network. I got it turned around and my component tester works now(!) Thanks Hacker Boxes - I've been wanting one of these for a long time.

jeasterl (author)rob_hunt2017-05-09

the diode network is a pain to solder but i can do it if i can figure out how it is oriented i cannot see a mark for orientation does the lettering orientat it ie. dose the "V" mark the first pin (and the dot) like most dip packages (pin 1 is lower left when reading the lettering)

that has got to be the smallest part i have ever concidered soldering i started electronics at the end of tubes and the begining of ICs

rob_hunt (author)jeasterl2017-05-09

it's really hard to see but the pin one indicator on the diode network is the dot. It needs to point to the same pin as the dot on the pcb

jeasterl (author)rob_hunt2017-05-09

found the dot it was where i thought it should be under the "V" in the lettering easier to solder then i thought, some paste solder and plenty of flux it's a beutiful thing

ArielB19 (author)jeasterl2017-05-13

it was easy for me to find the marking on the chip, but not on the board.
the "1" pin had a weird symbol, but i tracked the ground path the be sure.
"1" is away from the screen if anyone still wonders...

jeasterl made it! (author)2017-05-10

1 melted led later and it works

seaprimate made it! (author)2017-05-08

Only works when I hold it down, sometimes it will stay on for a second or two, but otherwise turns off. I originally desoldered, resoldered the LED because I read people had problems with the polarity, but I had it right the first time. There are no shorts or bridges that I can see, is that a capacitor issue? Also, when using a 9v battery rather than the barrel connector, the screen is dimmer, and never goes to menu. I'm out of ideas

seaprimate made it! (author)seaprimate2017-05-08

this is the same one where the 9012
transistor gets hot. Verified 9v with the dc power supply
with multimeter. Not sure if transistors can short internally, or if a
bad capacitor can cause this unsteady power. It acts as if batteries
were dying, even though it's from a steady dc power suppl. I also noticed that after frequent attempts to keep it on, it works better and better each time, eventually staying on and working normally through all the menu options, though once power is disconnected or I leave it alone for a while, it's back to not doing anything and have to go through the same repetitive process shown in the video

I'd love to hear any ideas on how to troubleshoot this.

seaprimate (author)seaprimate2017-05-08

Situation Solved!
Turns out it was a bad cap.
** It got easier to turn on the more I held the button down, like it was charging, but when left alone, the tester acted like it would discharge and go back to not wanting to turn on.
** I hooked my ammeter in line with the battery, and would watch the mAs used slowly and steadily drop while I held the button. Leave it alone for a while, and the mAs needed had crept up.
** Suspected it was a capacitor. Checked them both with my multimeter One would slowly move to infinite resistance like it was supposed to, the other one closest to the power supply had no resistance, meaning it wasn't working.
** Replaced the bad cap with one that came in the Modern and Analog electronics kit. After the first few tries of doing what it used to do, it now works exactly like it should, with both the dc from a wall plug transformer, and with a regular 9v battery!!!

So if the LED is in the right spot, but still having trouble, check the capacitors next with your multimeter, if the ohms aren't rising from 0.00 - O.L, you've got a bad cap. Now to 3d print a case!

KevinB482 (author)2017-05-05

Does anyone know what the pin mapping is for the TFT? I am trying to get it to work with the Arduino TFT examples. I've also tried the Adafruit ST7735 libs/examples too. Any thoughts?

Hi Kevin -

This doesn't exactly answer your question, but I just got done posting a short post on how to update the MCU code on my site. Nothing fancy, just a starting point, but it works....mostly :)

You might be able to get the info you need from the C files used in the directories I mentioned in the tutorial. Hope you get it working!

djcc2012 made it! (author)2017-05-05

Done! OK, I skipped the SMT parts. I had a lot of fun putting this together. Now on to testing!

HackerBoxes (author)2017-05-05

We're looking into this for you to see if we can figure it out. Just as a random note, when a transistor is drawings too much current (overheating) it may likely be due to one of the resistors around it not being the correct value.

g2em3 (author)2017-05-04

Help needed on the encoder.

I understand the 2 pin and the 3 pins get soldered.

What do I do with the 2 Tabs on the sides?

Do I need to stretch them out and inset into slots on PCB and Solder?

Do they not get used and I fold them out of the way or break them off?

HackerBoxes (author)g2em32017-05-05

Yes, the tabs on the sides of the rotary encoder should go into the corresponding slots on the PCB.

HackerBoxes (author)2017-05-02

Wow... It is super awesome to see all these testers getting built. Even the ones that don't quite work yet. Remember, "The path to expertise in electronics is beset with smoking heaps of gear and dreadful tangles of spaghetti code and cables." There is no shame in lifting the ocasional trace or letting the magic smoke out. Speaking of awesome builds, the live streaming build from Josh (of Practical IoT) is EPIC. Thank you so much for sharing that to the rest of us. Check it out here:

DCGuy (author)2017-04-28

I got my box today and am as excited as always! I made the tester in under an hour, but it only seems to power on if I hold down the encoder. Any ideas where to begin the troubleshooting for that? I get the menu but holding and turning does not change the menu selection and continuing to hold only shows the battery voltage.

kshowell (author)DCGuy2017-04-30

Same outcome with mine. I have checked for bridges , none found. I have not tried powering from barrel socket. Will check further tomorrow after work. It was a fun build :)

kshowell made it! (author)kshowell2017-05-01

Tried desoldering the LED and reversing orientation. No change for me. Decided to power from the barrel socket instead of the on PCB input leads. Put the LED back to original orientation. Works like a charm. Pulled the barrel plug and powered from soldered lead ... will not power. So I removed the wire leads from PCB and am powering from barrel socket. I will do some circuit tracing to try and solve why the other input pads will not power. But I am happy that it is working. Just sharing what worked for me. Hope this helps.

DanielB749 (author)DCGuy2017-04-30

HA.. got the same thing.. and my guess is that your led is also not turning on. So what you should do is prolly reverse the LED. The pos side should go to the left and the neg to the right. I think it was backward in the directions. I have no idea why it sorta powers up if the led is in backward but that was my issue.

eburman (author)DanielB7492017-05-01

Same thing happened to me. I had it in mind that the flat side of the LED was the cathode (-) side. So that's how I soldered it in place. WRONG! Brief flash of the OLED screen then nothing. So I looked at the LED more closely. The LED die is usually attached to the anvil and that's the true cathode side. If you look closely you can see that through the lens. So yeah I had it backwards. I reversed the LED and Viola! It's alive! Working as advertised!

DCGuy (author)DanielB7492017-05-01

Your guess is correct, it wasn't coming on. I'd already guessed the silk screen may show it backwards and was going to try that. Tonight I will know if that fixes the issue. Thank you very much for taking the time to confirm that!

DCGuy (author)DCGuy2017-05-01

Apparently the silkscreen on the LED is reversed. Once I desoldered the LED, reversed it, and put it back, everything works like a champ! Thanks guys, you saved my sanity.

BryceH18 (author)DCGuy2017-05-01

I added an additional 5 volt regulator to bypass the one on board and connected straight to pin 7 of the ATMEGA and it works just fine. It now just comes on when I apply power.

BrendonS12 (author)DCGuy2017-04-30

I am having the same issue

BobM16 (author)DCGuy2017-04-28

Check for solder bridges with a magnifying glass first. This is the easiest and most common problem. Check first on the encoder, 28 pin socket, and the two electrolytics.

bdennis4 (author)2017-04-29

im having some trouble with my component tester. when i press and hold the encoder button i see what looks like black and white cheese on the screen. when i release the encoder it shuts off. no other functions work. i used my microscope to solder the smd components and carefully checked the entire board for jumped or dry solder pads

eburman (author)bdennis42017-05-01

Check to see if the LED is reversed. I didn't see black and white cheese (whatever that is) but the screen came on briefly, solid white, and then black. Like you I thought maybe something was wrong with my surface mount components but they were looking good. So I checked the LED and I suspected that something was wrong. I reversed the leads and everything sprung into life!

NoviceAttempts (author)bdennis42017-04-30

I had the same symptoms, turns out I had the processor in backwards.

About This Instructable




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