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Hacker Public Radio

Your ideas, projects, opinions - podcasted.

New episodes Monday through Friday.

In-Depth Series

Hobby Electronics

Building electronic devices and kits, repairing electronics and learning about components and their uses.

What's in the Box! Part 1 - NYbill | 2019-05-28

NYbill opens a mystery box that arrived in the mail.

No spoilers. But, it involves soldering…

Pics for the episode:

Windmill is on the Fritz - Ken Fallon | 2019-02-15

In this episode Ken uses Fritzing tool to keep track of how a winter model village windmill is wired together. Leading to identifying the problem component.

Fritzing is an open-source initiative to develop amateur or hobby CAD software for the design of electronics hardware, to support designers and artists ready to move from experimenting with a prototype to building a more permanent circuit. It was developed at the University of Applied Sciences of Potsdam.

First impressions of the Odroid-go - dodddummy | 2018-12-10

I ramble on about my impressions of the Odroid-go, a 32 USD handheld system similar to a gameboy built to run game system emulators and various other free software. It’s also built to be harcked.

The summary is this is an easy to put together kit requiring no soldering, and runs classic console emulators pretty well. Well worth the 32 USD plus shipping in my opinion. Claims 10 hours of game play and that seems about right so far for me.

The systems emulated out of the box are:

NES, Game Gear, Gameboy, Gameboy Color, Sega Master System, ColecoVision. Other systems of similar or earlier vintages have emulators that you have to install separately and boot into to run. I don’t think it will emulate newer systems. No Gameboy Advance emulator and I don’t see a Mame emulator. However, I do think this ‘might’ support Mame for some of the early arcade games like Asteroids and Space Invaders.

Blinking LED - Ken Fallon | 2018-09-21

During the New Year Show Ken soldered a component tester. Unfortunately this did not work.

NYBill offered to fix it and he succeeded in his show hpr2591 :: International Troubleshooting. When he shipped it back he included two 555 timers with the message: Now, figure out how to make LED's blink with those 555's!

In this show Ken uses the online guide FLASHING L.E.D. USING 555 TIMER By Trilesto to do this.

Raspberry Pi Temperaturator - b-yeezi | 2018-08-21

Items used

  • Raspberry pi 3 B
  • 0.25 watt resistors
  • Reusable breadboard
  • One Wire thermal probe
  • Various jump wires

International Troubleshooting - NYbill | 2018-07-09

NYbill troubleshoots a DIY kit of Ken Fallon's.

The new toy:

AmScope SE400-Z
(The microscope has a nice working height underneath it so you can get your hands and tools in there.)

The offending chip:

Pics for the episode:

Electronics Calculator Kit - NYbill | 2018-03-22

NYbill talks about building a $16 electronics calculator kit.

Kkmoon DIY Calculator Kit:

Pics for the episode:

Just to save anyone from searching for some secret mode on their calculators, I misspoke. I mention using my TI calculator in “Degree Mode”. I meant to say “Normal Mode”. It just happens to say DEG on the screen in tiny letters. What can I say, I’m easily distra

Oh look at that!

The Lost Episode Part 2 - NYbill | 2017-10-24

A follow up to “The Lost Episode”. Flashing the blank Atmega328p chip to get bring a nonworking Transistor Tester Kit to life.

There are a lot of these kits out there. Different shapes, colors, and capabilities. In my case the kit was called a: 2578AY-AT. The firmware for this particular kit is: mega328_color_kit.

    lsusb (get bus and device ID numbers.)
    sudo chmod +777 /dev/bus/usb/*bus_ID/*device_ID

    avrdude -c ‘your programmer’ -p ‘your chip’
  • In my case:
    avrdude -c usbasp -p m328p

Avrdude should communicate with the programmer and verify the chip is ready to receive instructions.

From here Avrdudess helped as I was able to use the ‘verify’ options after a write to see there was an error. Avrdudess also let me correct the error by changing the E-lock value to 0x04. Then the flash would write.

Remember to write the hex file first and the eep file second as hex would over write a eep file if it was written first.

The Lost Episode - NYbill | 2017-10-05

NYbill puts up a ‘Lost Episode’ recorded in October, 2016. A comment for Ep. 2369 asking if I have ever built one of the many Transistor Kits available jogged my memory. I still had the recording so, I’ll just throw it up. I’m not sure how many pics I can find for the episode. I’ll put up what I can.

And just for Mike Ray, I’ll leave in some bench noises I would usually edit out. ;)

The soldering vice being used:

Solder sucker:

The kit (This looks like the one I ordered. But, it's been about a year gone by now. This one shows firmware running on the chip in the pics. You can take a gamble on it if you’d like):

Pics for the episode:

Little Meters - NYbill | 2017-08-31

Listen to more things clicking and beeping!

NYbill does a quick review of two more inexpensive multimeters, ANENG models AN8002 and AN8008.

Bonus noises! I recorded next to an open window on a gusty day. Oops…

Building a Digital Clock Kit - Dave Morriss | 2017-07-06

Building a Digital Clock Kit


In April 2017 my son and I decided to each build a digital clock. I had been interested in the idea since seeing Big Clive build one on YouTube, and I think my son had been similarly motivated.

He found one, which I have linked to below. It's smaller than the one shown by Big Clive, comes from ShenZhen China, and costs $5.35 (about £4.18) postage free. It takes a long time to arrive, so patience is needed!

There are many digital clock kits on eBay, and lots of YouTube videos showing how to build them. I think it's a great project for someone wanting some soldering practice which is a little more demanding than a beginner project.

One type to avoid, I think, is the surface mount type. The one I have uses a through-hole PCB, but I have seen some that provide SMD (surface-mounted device) components. That type of soldering is beyond me at the moment (though my son has been teaching himself to do it).

Long notes

I have provided detailed notes detailing the unpacking and building of this device, with photographs. These are available here.

Bad Caps - NYbill | 2017-06-15

NYbill talks about repairing a motherboard.


Even though I go into a bit about different types of capacitors I didn't plan on this being an episode about capacitors themselves. Even though I mention some different types. Bonus, there are also Trimmer Caps.

And yes, I know LCD's don't have a trace. The old school CRT user popped out there. You all knew what I meant.

Also, I know I mentioned getting a 90 piece cap set from Banggood. I decided to order proper Nichicon replacements from Digikey. Had this been a repair for myself, I would use the no name caps I ordered from China. But, being this repair is for a friend, I figured I better get the real deal. ...BTW they were 220 uf caps.

(Thanks Jezra for the musical interlude. We were joking calling it, "Time Passing".)

Pics for the episode:

The DSO138 Oscilloscope Kit Part 2 - NYbill | 2016-10-26

In this episode NYbill talks about finishing the DSO138 Oscilloscope kit.

The DSO138 Oscilloscope Kit (part 1)

3D printable case:

The kit with pre-soldered SMD parts:

Without pre-soldered parts:

The forums:

Pics for the episode:

The DSO138 Oscilloscope Kit - NYbill | 2016-05-12

In this episode NYbill talks about building a DSO138 Oscilloscope kit.

A first look at the Owon B35T Part 2 - NYbill | 2016-04-21

In this episode of HPR you get to hear more of the things on NYbill's electronics bench that make clicking noises.

The review of the Owon B35T's continues. Bluetooth is now working. And we get an inside look at the meter.

A First Look at the Owon B35T - NYbill | 2016-04-07

You are along for the ride as NYbill takes his first look at another inexpensive Multimeter.

This is part 1 of a quick look at the Owon B35T True RMS multimeter with Bluetooth.

BlinkStick - Dave Morriss | 2016-02-22



In late 2013 I noticed the local Edinburgh Hacklab were offering soldering courses building a BlinkStick. I offered to sign my son Tim up to the next course since he wanted to learn to solder. He couldn't afford the time at that point, but we agreed to buy some BlinkSticks to build at home.

This episode describes some of our experiences with building and using the device.

The version we bought and built was the v1.0 release, since that and the BlinkStick Pro were all that was available. The base version now available is v1.1, and there are several other products available from the manufacturer in addition to these. The company is called Agile Innovative Ltd, based in the UK.

I have written out a moderately long set of notes about this subject and these are available here

Multimeter Mod's Part 2 - NYbill | 2015-09-16

NYbill talks about the second modification to his UNI-T UT61E multimeter. In this episode the switch and auto-timeout circuitry is installed.

This is a follow up to Multimeter Mod's Part 1:

A video of Asphere's 3D printer in action:

Pictures for the episode:

UNI-T UT61E Review - NYbill | 2015-08-31

NYbill does a quick review of his favourite multimeter for electronics, the UNI-T UT61E:

A photo of the inside and outside of the meter:
picture of the inside of the meter

I forgot to mention or show a picture of the data logging cable. I never use this feature so I tend to forget its there.

Multimeter Mod's Part 1 - NYbill | 2015-08-05

NYbill talks about modifying his UNI-T UT61E multimeter to add two features he finds lacking.

In part one an LED back light gets installed for the LCD screen. Part two will cover the second mod, a auto-time out feature to save the units battery.


Gathering Parts - NYbill | 2015-07-21

The web site that started this all:

Big Muff Pi:

Parts Distributors:

Hammond Box:

Joe Knows:

Picture of the gathered parts:

When I made the reference to "two red lips" regarding resistor colors I didn't quite explain what that meant. It was a way I learned, way back when, to remember which color was which number on a resistor. I hadn't thought about it in years. It used rhyming and references scheme to line the colors up with values.

0- Black - It's a "no" color, a zero
1- Brown - 'brow-one'
2- Red - Two red lips
3- Orange - Orange tree
4- Yellow - Yell for help
5- Green - a five dollar bill is green
6- Blue - Blue and sick
7- Violet - Violet heaven
8- Gray - Great
9- White - White wine

Making Waves-The DSO Pocket Oscilloscope - NYbill | 2014-05-07

NYbill discusses the DSO Pocket Oscilloscope v3. A few test circuits are set up to put the scope through its paces.

The DSO at Adafruit:

The 555 timer chip:

The script used to blink the Teensy:

Pictures for the episode:

Low Tech Fab (PCB Etching) - NYbill | 2013-01-31

Due to an error in the encoding (ken's fault) the episode is been re-transmitted - sorry all

I this episode NYbill talks about etching copper PCB boards at home..

Photo collection:

Surface mount breakout board layouts:

FTDI FT232RL Data sheet:

Sparkfun FTDI breakout board schematic:

Tinting fluid (I didn't buy it here. This is just a good pic of the product I used):

Anyone driving through the Capital District of New York, this old, locally owned, electronics shop is still kicking:

A few things I forgot to mention in the episode. The muriatic acid/hydrogen peroxide etching solution can be used multiple times. Store it in plastic or glass containers. The tinting fluid can also be reused. But, it will need to be agitated and or slightly heated (place container in a bath of hot water) before reuse as the mix will settle out.