At my workplace we have a small electronics workshop where students can get help with projects, borrow equipment, buy tools and order components. They wanted to make their physical space a little more visible with a sign that described what they are doing. Instead of electronics workshop they are know by the name ELAB for electronics laboratory.

DESIGN

After a small brainstorm with my colleagues I got the task to design something that would make people recognize the place only by looking at the sign. The outline of the letters was designed with our company font type. Some of my thoughts was that it should be colorful, 3D and physical with things the user can interact with.

The basis for each letter are made by sheets of MDF. The wall where they should hang had plenty of empty space so I wanted to maximize the size of each letter. The only problem was that the letter A was a bit wider compared to the other letters, so A defined the total size for the rest. The four letters was each converted from a SVG file into a DXF file and laser cut on our CNC Laser cutter. We talked about painting the MDF plate but dropped the idea since we wanted to finish it as fast as possible.

My idea was to decorate the letters a bit like The Circuit Board Coffee Table were old printed circuit boards was used to cover the wooden plate. Compared to cover a large rectangular area it took a little more puzzle skills to do the same with narrow, triangle and round areas. The interesting thing is that all most all of the e-waste that is used has been used at my workplace in some form. Judge the result for yourself.

MODULES OF EACH LETTER

Have a closer look at the pictures below to study what each letter consist of.

E: fan, LCD from an oscilloscope, pump laser controller front panel, PCI server network card, CPU, power supplies, diskette, LEGO NXT controller, soldering kit.

L: VGA KVM switch, fan controller, LCD control panel, PLC interface card, router, Altera DE2 board.

A: red warning lamp, control board from an analog video camera, CAN development kit, Analog Discovery Sharc developer kit.

B: RAM module, oscilloscope control board, 8 bit computer control board, Anchor Chips development board, Atmel STK500 programmer kit, home made perf board, Devkit 8000 ARM Cortec A8 evaluation kit, multimeter, Analog Devices control board.

Feel free to use my idea to design you own project or reach out to me if you want me to design some e-waste art.

FUTURE DEVELOPMENT

A future development for the sign could be to make it more interactive so a LCD could write different messages, a blinking LED, a button that would turn on and off a fan or a speaker making a random sound when a person is detected by a motion sensor.

Indlægget Electronics Waste Sign blev først udgivet på Daths Garage.

Later on I learned about using shift registers and dedicated LED driver chips for controlling color and patterns. Once I came across some LED tubes from a big LED screen. Each stack of 15 LEDS (5 Clusters of red+green+blue LEDs) was controlled by a MBI5025 16-channel controller through SPI. I never made anything useful out of them except for turning all the LEDs of the same color on so I could use them in a similar way as a simple RGB light strip.

ADAFRUIT NEOPIXEL LIBRARY

Later on the WS2812 was released around 2013. In the beginning it was a bit challenge to control because of the strict timing since it only had a single data pin and no clock. That changed when Adafruit introduced the NeoPixel product line together with the brilliant Überguide describing how to use the NeoPixel library. It can be used to control WS2812 (IC embedded inside LED), WS2811 (external driver IC) and SK6812 (RGB+white LED).

Other very useful Arduino libraries for NeoPixels is FastLED and WLED. WLED can be used together with an ESP32 as a webserver to control the setup and light patterns, it also integrates with Home Assistant. I have used WLED for another WS2812 project in the my garage. This will be described in a later post someday.

HOW IT WORKS

Back to this story… The reason why I started looking into making a LED strip with individually-addressable RGB color pixels was to decorate my daughters bed when she was a baby. I looked into different things and found this video by David Bick which I found interesting. David seems like a nice guy since he shared his code on GitHub.

His project was about making a jar of fireflies that would lit up when you move it, detected by an accelerometer. Since I wanted it to stay on when power is applied I removed the detection part.

The code has different control parameters than what I needed for my idea. I will briefly describe below, but I refer to the code for the full overview.

First the pin for controlling the NeoPixel is defined and the numbers of pixels of the complete string. MAX_GLOWING_PIXELS defines how many pixels will be lit at a random time ranging between only a single pixel up to the complete string. The three values I played around with most of the time was: hueCenter, hueRange and baseSpeed. The last value defines how fast a given pixel will lit up and fade out combined with a random part. To understand the two other variables a basic knowledge about the Hue color space is needed. hueCenter defines the center color and hueRange defines how far the colors spread out. This part was a bit trial and error to learn how it worked. In Davids code he wanted colors in the blue, turquoise and green area to mimique fireflies. If you wanted it to look more like fire you should change the base color the orange area and make it spread out from yellow to red. I just wanted it to show all colors so I picked a hueCenter in the middle (turquoise) with a wide spread (from red to red). When you play around with it you will understand.

After I found the values I found pleasant I made a small box for the Arduino Nano to control the light strip together with a 5V power supply to power the LEDs. Remember to read this part of the Überguide to understand how to specify the required power to your string.

It was used on by daughters bed for a couple of months but for the following Christmas is was brought to my workplace for decoration and is still in use right now.

VIDEO

The video below shows the changing pattern. Speed, color center and color range can be changed by reprogramming the Arduino.

WANT YOUR OWN

From the description and links in this post you should be able to build your own. But let me know I you want me to build a complete setup for you.

By changing the original Arduino Nano to an ESP32 it would be quite easy to have a webserver where you could change the relevant values for different string lengths and light patterns.

Indlægget WS2811 Programmable Christmas Lights blev først udgivet på Daths Garage.

INTRODUCTION

Before my wife and I had kids we used to have a small tv in our bedroom. That ended because our first daughter slept in our bedroom so we got rid of the tv because it interrupted her sleep. Now when our kids are getting older we wanted to get a tv again.
For some reason I had a hard time finding a tv that fulfilled my requirements.

• Small display size below 27″.
• Cheap, I don’t want to spend around 2.000 DKK for a new tv.
• I was willing to pay around 500 DKK for a used tv.
• Must be full HD resolution.
• Need to support DVB-C for our cable tv signal.
• I don’t want an ugly plastic tv (I used to have a Bang & Olufsen BeoVision 6).

Especially the last requirement was the hardest to fulfill. Many of the cheaper tv’s just look very bad and cheap. And if I found a used Sony or Samsung tv, that had a reasonable design, it would cost more than 1.000 DKK used. I kind of forgot about the tv until I found a Samsung tv that was left for bulk waste just around the corner of my building.

THE BROKEN TV

I picked up the tv and found the remote control lying next to it. At first sight the tv looked fine; the display wasn’t damaged and the cabinet looked fine. When I brought it home to my workshop I tried to power it on. The red standby LED turned on for a moment and then turned off again. The remote control didn’t changed anything. I started to inspect the tv and found out that the lower left corner had some broken plastic. To investigate if this damaged was related to the power on problem I unmounted the back part. With the electronics revealed I started to search for loose connectors, capacitors or other components which could have taken damage from the force that broke the corner. After a while I discovered that a corner near a screw mounting hole on the PSU PCB had some cracks. I unmounted the PCB and saw that the crack had disconnected two copper traces. I inspected the PCB and found out which components the copper traces was supposed to connect and made a repair by mounting insulated wires between the connections. I reconnected the PCB and tried to power on the tv. First sign of life was that the LED stayed on. Then I pushed the standby button on the remote control and the tv came to life. I didn’t had an antenna signal to test with but the menus worked and the HDMI input also showed a picture. So I assumed that the problem was solved.

HOMEMADE WOODEN FRAME

Now I had a working tv with a broken plastic frame that I didn’t want to try to repair. First I thought about just throwing away the complete frame and just use the display panel, but I needed something to hold the other parts like PSU, control board and speakers. Then I thought about building a plate on the back of the panel to mount the modules on. This could have worked for a workshop tv but this one had to be used in our bedroom so I needed to improve a little on the design.
In my junk pile I found some old bed slats that had the right dimensions for building a frame around the display panel. Since I didn’t like the color of the light pine wood I found some teak stain to give it a darker color. Then end result looked nice, but it was a mistake to glue the frame before applying the stain. Because the stain couldn’t bind on the corners because of the glue. The inner dimensions of the frame fits perfectly with the viewable area of the display. The dimensions for the frame was found in the datasheet of the panel. Two bed slats holds the panel in place and are spaced so the two PCBs can be mounted on them. Speakers are mounted on the button part of the frame. I haven’t found a perfect place for the IR receiver, I might drill a small hole in the frame so it can be mounted there.
I need to warn you that it is NOT a good idea to mount the PSU PCB directly on top of the wood because of fire risk because of the mains power. You need to mount an insulator in-between the two.

GALLERY

CONCLUSION

I really like the finished design of the tv – it’s very unique and matches the rest of our teak furniture. Many of our friends and family don’t really recognize that it’s a tv the first time they see it. I agree that it looks a lot like a small blackboard when it is turned off. The best thing about this project was that I got a tv and ended up paying nothing for it and had a fun time repairing and building it.

Update July 2026

The tv has been hanging unused in our kitchen for a couple of years. The other day I wanted to turn it on. After a while there was a loud bang and the picture went out. A small tantalum capacitor on the PSU board finally gave up. I didn’t want to spend the time on reparring the PSU so the tv finally was send to electronics recycling.

Indlægget How to Upcycle a Broken LCD TV blev først udgivet på Daths Garage.

INTRODUCTION

Often when I walk around in my neighborhood or driving around throughout the country I wonder what people hides of weird projects, interesting hobbies or unique collections in their basements, barns or attics. I always love to meet people who have an interesting technical interest and learn about their passion.

Some time ago I got the opportunity to visit a place which sparked my interest. An elderly man living in the countryside that collected old radios – including a lot of other stuff, I later found out. 

I wasn’t sure what to expect because old radios aren’t my main interest, but still I found it interesting to have a look at it and hear some good stories, and who knows, maybe stumble upon something interesting. I have been following the story about how Computer Reset reopened again to sell out everything and have been very fascinated by all the treasure hunts people have been going to find the most exotics and rare computers and equipment. Unfortunately it isn’t possible for me to go to Dallas, TX just to buy old computers. But I thought this could be my little treasure hunt for something I haven’t seen before.

Our appointment was just about to be cancelled because of bad weather with strong wind and snow so I was a little worried if it was possible to go to his place in the countryside and more important, if I was able to drive home again. When I finally arrived at his place he also shared his worries about the corona virus because of his bad health. So we agreed on keeping a safe distance and being extra careful.

THE ELECTRONICS WORKSHOP

When we entered his barn the first room we came into was a combined electronics workshop and storage room. It seemed like this was where his collection had first started. It was a nice and insulated room with his small electronics repair table in the corner. It looked like a time capsule of an old electronics repair shop from many years ago. All the walls were covered with small drawer racks filled with different kinds of electronics and mechanics components. The tables were filled with different kinds of measuring instruments like oscilloscopes, power supplies, meters, electronic devices and cables. 

The rest of the room was organized as a storage space with tube radios, gramophone players, reel-to-reel tape recorders, old televisions and everything else. Ranging from crystal radios from the 1930’s to combined CD, radio and cassette stereos popular around the 90’s to modern DVD players. Well actually I think DVD players are almost obsolete nowadays and replaced by online streaming services. By organized I don’t mean sorted and organized on shelves or similar, well some of it was, but most of the devices were just stacked from floor to ceiling in big piles. In-between there was a small footpath between the different rooms. In one of the rooms it was simply impossible to see everything because it was just filled up from the back wall and five meters forward. The only way to get to the equipment in the back would be to remove everything in front of it!

Don’t get me wrong – the place was not a mess, dirty or disgusting at all. But there were just so many devices everywhere that I would drown in there and never get anything done because my head would get crammed up by frustrations about where and how to start organizing everything.

SAPRE PARTS ROOM

We left the nicely insulated rooms and went into the part that had originally been a place where the pigs lived (the place used to be a farm many decades ago). This part was used for storage of parts, components, doors, wood and about everything else. One drawer was full of old potentiometers another with turning knobs etc. At the far end of the room there was a steep staircase to the attic. 

THE BARN ATTIC

I was overwhelmed by all the impressions I got from looking around when I got up in the attic. My best way of describing it is to compare it to a library with rows and rows of shelf systems. But instead of books and magazines organized by themes or name it was spare parts for old radios organized by type. One shelf with loudspeakers, another with cables, vacuum tubes (my estimate was that there were several thousands in the many boxes), mechanical devices, repair manuals etc. There were so many different things, and again more radios. I was amazed that all the things that were up here had come through that small steep staircase. 

I was told that every radio that had been put here for storage had been tested and worked when it was left. However I’m afraid that a lot of the equipment has degraded over the years because of the changing temperature between winter and summer, the humidity in the air and just the fact that when old electronics equipment is left unused for decades it just starts to decay. Capacitors will dry out and leake, rubber bands will become brittle or crack, metal will rust, wood and plastic surfaces will mold. So it was a little sad to think about the destiny for all the things I saw up here. But still it was so fascinating to look around and discover new things when seen from a different angle. 

HOW IT STARTED AND THOUGHTS ABOUT THE FUTURE

When we were back down in the workshop it was easy to see that he enjoyed the impression he could give visitors that experied his collection for the first time. He explained that he had started off by collecting Herofon (or Herophone as it was spelled on some of the first models) and then later Arena. But it was hard for him to let go of anything or even pass the opportunity when more were given to him. Because he thought it was so interesting to collect it and save their history.

He also explained that he suffered from poor memory and a health that was slowly deteriorating. To my happy surprise he had made up his mind about what would happen to his collections if he would come to a point where he could no longer take care of it. Instead of people with no knowledge about the value of the items would come and clean up everything and throw it out, he had made an agreement with a museum that can come and pick up what they want for their own collection. 

To my surprise he also asked for my contact information and what was my main interest. Then maybe later this year when the corona virus has hopefully decreased its impact I should be welcome to come back and see if I could find something I wanted! I think he liked that a person like me, many years younger than him, could also recognize the value of old electronics with a historical impact. 

AFTERTHOUGHTS

On my way home I thought a lot about the visit, his collection and how it was organized. It was a great eye opener where I realized that I really need to keep focus in my own collection and what is the most important to me. I will certainly not end up in the same situation where my passion for classic computers and other historical electronics gadgets take over all my available space. I would rather have 10 unique interesting items in great conditions than a hundred different computers in various not working or incomplete states. I also need to have a heated place to store my equipment so it will not degrade over the years. I’m also searching for the best solution on how to organize my computers on shelves and glass display cabinets for the smaller items. Like many other computer collectors I have been looking for something similar to this chrome-plated steel lattice racks and for the smaller gadgets I’m going for some IKEA Detolf display cabinets.

Another lesson learned is that you can’t just collect computers, but instead you need to focus on a specific brand, time period, special kind of devices, in order to make it more manageable and limit the number of devices. I’ve tried to formulate and write down some guidelines for my own classic computer collection to specify what I find important.

Disclaimer: I was given permission by the owner to show these pictures but I promised him not to reveal any name, address or anything else about his place. If anyone is interested in his collection contact me and I will try to answer your questions.

Update 15/6 2025

The owner of the collection has decided to sell the place because of age and a bad health. Some of his collection went on to a museum and other personal collectors but most of it will be thrown in a big container for electronics recycling. I got a few items through a related person.

Indlægget A Visit to the Radio Collection blev først udgivet på Daths Garage.

Introduction

Over the years I have come across different giant projects. There is a Giant Arduino Uno, a Giant LED, a Giant Resistor ohmmeter, a Giant NE555 footstool and lately a Giant SD card. I’m not sure why people think is so interesting to upscale tiny objects from around there lab, I guess there are different stories and reasons. But now there is also the Giant Vacuum Tube Lamp and here is my story about it.

Inspiration

The other evening I was trying to get an overview of all our digital images that were spread all over the digital place. From old smartphones including online backup services that were about to expire or filled up, like Dropbox, Google Drive and OneDrive to different folders in different computers and backup hard drives to an old camera in a drawer. On an old hard drive I found some very interesting images taken longtime ago at a music festival with the famous, now dead, Danish musician Kim Larsen that I have heard on the radio since my childhood. In the background of the stage stood four vacuum tube models the same height as a person. They looked rather realistic with orange light simulating the filament heater and blue light simulating the fluorescence that can be seen in some power tubes. My guess is that they should look like EL34 power tubes typically found in guitar tube amplifiers. I remember that I thought they looked so cool and wanted to build something similar. But I never got anything done about it – until now.

When I saw the images again I got the same excitement and started to search around for the part that would define the rest of the design – the glass envelope. I was surprised to find many different products available. Typically used as a glass bell for displaying flowers or other creative things as an interior decoration. Most of them had a dome shape at the end without a tip resembling the exhaust tip on a vacuum tube. This was not a big problem because it looked a lot like the EL34 where the exhaust tip is hidden at the bottom of the tube between the pins. The dimensions of the glass bell gave me some dimensions to continue my work with the search for the rest of the parts. An EL34 measures 33.3 mm in diameter and is 98 mm high including the socket but without the pins. The closest I could come to this relationship, using the largest glass bell I could find, was one that had a diameter of 21.5 cm and a height of 52.5 cm. This gives an upscaling factor around 7 for both diameter and height.

Design and construction

After settling on the outer dimensions I started to search for inspiration for the internal structure of the vacuum tube. I wanted it to look a bit more realistic than the ones I saw at the stage and another project I found online.

The outer structure of the tube is inspired by an EL34 tube mainly because the glass bell has a rounded top like an EL34 without an exhaust tip at the top. The connection pins on an EL34 is connected to a brown or black socket part that would be a perfect way to connect the glass bell with the connection pins on my model. 

The internal structure is inspired by the front cover of a book from my collection called Build Your Own Audio Valve Amplifiers. I didn’t want it to look like the internal of an EL34 because there isn’t much to see other than a big solid metal plate. I found an EF89 in my parts bin that has a nicer metal grid around the heater and grid wires that can be seen beneath. The EF89 is commonly used as a R.F. Pentode in AM/FM radios. 

Starting from the inside and out the heater is built from two 230V LED filament light bulbs mounted top to top. Around the bulbs an enameled copper wire is wrapped imitating a grid. Around this grid another grid is wrapped around two threaded rods. The last layer is a thin perforated metal plate imitating the outer metal plate. The six threaded rods are held together in each end by the insulating spacers made from laser cut acrylic plates that are sanded to give them a matt finish like mica. At the top end two of the threaded rods are extended to work as mounting for the getter ring. At the bottom the internal structure of the vacuum tube is connected to the socket by thin copper tubes going from the threaded rods down to the pins in the socket. To straighten the copper tube before bending to the right angles I used my Tube Straightening Tool.
The socket is made by laser cut plates of plywood glued together to give the right height. The plates were made with holes for the eight pins which are glued on. The curved surface of the socket has been sanded down and plastered before a spray primer has been applied. The last step was to paint it with a black glossy spray paint to make the surface look piano black.
The two light bulbs are connected in parallel and the power cables to them are routed through two of the copper pipes and down through two individual pins and connected to a transparent copper wire. 

Final details

There are still room for minor upgrades:

• Make larger cutouts in the pins where the power cables go through them.
• The getter ring should be sanded and painted silver to look like metal.
• The top part of the glass bell should be painted dark silver to look like vaporized barium.
• As a lamp the amount of light from the two light bulbs is perfect, but as a model of a vacuum tube it would be nice to add a light dimmer to make the filament look a bit more realistic.

Parts list

1x Glass bell – glass envelope
9x 12mm round plywood plates – socket
8x metal tubes – pins
6x M6 metal threaded rods with nuts – internal structure
2x acrylic plates – insulating plates
1x acrylic circle – getter ring
2x LED filament light bulbs – filament
8x copper tubes – connection between pins and internal structure
1x Enameled copper wire – grid
1x Thin perforated metal plate – outer plate
1x 230V transparent copper wire 
8x Acrylic plate for connecting pins and copper tube
4x Acrylic plate for light bulbs
1x Acrylic socket top plate

Specification

Final thoughts

I think my giant vacuum tube lamp turned out almost as I had hoped for when I imagined it in my head. I spend the most time on completing the socket because I wasn’t happy with the result after the first time I painted it. The surface wasn’t smooth enough, so I had to sand down the paint and primer to make the surface more even before repaint. This had been a much easier task if I had had the right tools like a belt or disk sander to sand the wood in the first place. Much of the design has also been work in progress while building it since I did not made a complete 3D drawing of the vacuum tube prior to the build. That made it necessary to adjust and modify some parts throughout the build.
I think the final result looks much like a real vacuum tube (except for the bright heater) and I’m especially happy with how the connections from the pins to the internal structure has been made with thin copper tubes that looks realistic.

If you have any feedback please comment below or contact me. If you are interested in buying your own giant vacuum tube lamp please contact me and convince me to make another one for you.

Indlægget Giant Vacuum Tube Lamp blev først udgivet på Daths Garage.

What is it?

While searching around the web for nice electronics decorations and inspiration to The Circuit Board Coffee Table I found a nice digital clock built on a breadboard based around two different types of integrated circuits: the 4026 decade counter and the 4060 14-stage counter/divider. I’m fascinated by nice looking breadboard projects so I thought I could build it so it would look a little more sleek. This digital clock reminds me about the TTLCLOCK even though that contains a few more components. Another digital clock from KABtronics that contains many components is their Transistor Clock which is truly a nerdy wall decoration.

Before I learned about programming and microcontrollers I always kept away from electronics project involving anything that needed programming like microcontrollers, microprocessors or EEPROMs. I wasn’t sure where to start to get to learn about it, and I couldn’t imagine how they worked. Instead I would have loved to sit down and understand the schematic and build this digital clock when I was younger, since it is purely logic circuits and even some diode-resistor logic.

How does it work?

The nice thing about this breadboard digital clock is that it is rather easy to understand how it works, because it is divided into different modules.
The first part is the 4060 14-stage counter/divider connected to a 32768 oscillator, which gives a frequency of 32768 Hz/2^14 = 2 Hz. Two buttons Minutes and Hours are used to set the clock by increasing the frequency so the clock counts faster. The 2 Hz signal is input to the first 4026 that works as a divide by 2 and outputs a 1 Hz signal. The 4026 are designed to directly drive a 7-segment LED display rather than outputting a BCD signal that needs a BCD to 7-segment converter, this helps to reduce the component count. The two LEDs are also connected to the 1 Hz signal to indicate the seconds.
The counters for ones of seconds (red wires) and ones of minutes (grey wires) counts from 0-9. However the counters for tens of seconds (yellow wires) and tens of minutes (green wires) only counts from 0-5, and needs to reset afterwards. This is done by the resistor and the three diodes that works as a three input AND gate, when segments E,F,G are turned on (this combination is first met when count equals 6) the counter is reset. The ones of hours (brown wires) also counts from 0-9 but the tens of hours (blue wires) only counts from 0-2. These two counters must be reset when the combined counter equals 24. This is again done by the three diodes but now connected to a combination that first happens when the counter reaches 24 and now both counters are reset.
No resistors are needed between the 4026’s outputs and the 7-segment displays because the outputs only supplies around 1-3 mA. Since the LEDs in the 7-segment displays can not handle a 5 V supply voltage the two diodes 1N4007 are needed to give a voltage drop.

Why did I build it

Why would anyone bother to build something like a digital clock on a breadboard and waste a couple of hours on it? First of all I think it is fun to build stuff on breadboards even though they can be buggy, have bad wire connections and works bad at high frequency. Despite of all the wires and connections the clock actually worked the first time I powered it up. I know breadboard computers like the one from Ben Eaten is much more cool to look at and play with, but I like the simplicity of this design and its also a little more self contained – just connect power and it works. Playing around with breadboards is also a good way to learn about electronics because it can be more intuitive compared to multilayers PCBs with SMD components.
Another reason for building this digital clock is that I have a tradition every year with some old classmates to gather for Christmas lunch. Then we each have to brings some small presents for a Danish tradition called Christmas package game. Some should be repeats from last year and some should be homemade – this will be this year’s contribution.

Want your own?

If anyone is interested in building this digital clock on their own, the parts are listed in the link at the beginning. If you prefer to buy everything as a kit I might be considering to offer it with every component needed or in a fully assembled and tested version. Please contact my for inquiries.

Video

Link to the schematic

Indlægget Breadboard Integrated Circuit Digital Clock blev først udgivet på Daths Garage.

Background

The first microcontroller I learned to program and got to understand the architecture of was the Atmel ATmega16/32 in a DIP40 package programmed with a STK500 board that can also be found on The Circuit Board Coffee Table. This chip fascinated me with all it’s build in peripherals inside a single chip. Other chips that I later played around with were the Microchip 16F877 and 18F4550 with USB interface. When I got interested in retro computing I came to know about 6809, 6502, Z80 and 8088/86, which all shared the common DIP40 package. I found myself collecting these devices without really knowing why and not knowing how to display them. I just knew I didn’t want to start a huge CPU collection, so I limited myself to the DIP40 form factor. Then at a natural museum’s shop I saw this little showcase with butterflies, wondering how cool it would look like with old DIP40 ICs in it instead of animals. I found the perfect frame for the showcase with an IKEA HOVSTA frame that had the right depth.

The ICs would be mounted in precision machined IC sockets soldered onto prototyping PCBs so it would be possible to swap them around if some was added or removed from the collection. 

Scope of the collection

The overall theme of the DIP40 Frame of Fame is famous DIP40 microcontrollers and microprocessors with a few exceptions by type and package. Since the DIP40 package is now almost obsolete with new microcontrollers, breadboard friendly microcontrollers, mounted on a DIP40 size breakout board, are also included in the collection. This is my little version of a CPU collection with items I think has an importance to computer history. The name DIP40 Frame of Fame is somehow self explaining but is inspired from the Chip Hall of Fame.

Below is a list of the 21 ICs that can be seen in the DIP40 Frame of Fame sorted by release date and with a short description of specifications and a justification for relevance.

Specifications

Disclaimer: The above information and years are based on Wikipedia articles and datasheets and are my best guesses. If you have any corrections you are welcome to contact me.

Indlægget DIP40 Frame of Fame blev først udgivet på Daths Garage.

It all started with an old factory that was about to be cleared of inventory before demolition. I was allowed to get a lot of old SAIA PCA1 PLC systems for free I just had to remove them myself. Unfortunately I don’t have any pictures from the PLC room. But imaging a room the size of a small office packed with PLC racks along all the walls of the room. Unfortunately the room had been vandalized so the cabinet doors had been broken open and some of the equipment had been smashed.

However I managed to salvage around 20 complete PLC systems from the room together with several hundreds of SPDT relays mounted in the racks and connected to the outputs of the PLCs. The relays are still lying around somewhere in a box waiting for me to build something cool out of them like playing with Digital Relay logic, build a Digital Relay Clock, or something like a Single Board Relay Computer. However my main reason for keeping them is to build a relay version of the discrete logic in the SN74LS181 4-bit ALU.

In each PLC unit there was a motherboard consisting of an Intel 8085 8-bit microprocessor together with 62256 RAM, 8255 PPI, 8251 UART and 8253 Timer chips and the corresponding control logic. On two modules on top of the motherboard up to eight I/O boards were connected. As I understand it, these boards were ADC input board, multiplexer boards for BCD switches, output TRIAC boards, mixed input output boards, communication modules to passive extension housing modules without the CPU but with room for eight extra I/O boards. 

For a long time I didn’t know what to use all that equipment for, clearly it didn’t work. Most of the motherboards had clear signs of leaking backup batteries and some was missing the program EEPROMs. I kept them because I wanted to build a nice visual decoration out of it.

One night I was searching around on Google image search about circuit board decoration and came across Chris Harrison’s Circuit Table. Immediately I knew what to do with my pile of old circuit boards and computer motherboards, I wanted to build something like Chris’s table. Instead of the IKEA Lack table that he used as a basis I wanted to go with a bit more industrial look. I started to make a drawing in Sketchup with one of my favorite building materials 20×20 extruded aluminum profiles.

The final design ended up much like I had imagined with a nice industrial look. The PCBs should be mounted under the top glass plate on a wooden plate. The lower horizontal part of the chassis stabilizes the legs and makes it possible to install a second wooden plate as a shelve by adding some extra support beams.

Parts needed for the table:

• glass plate 10mm, 135×75 cm
• wooden plywood plate(s) 12mm, 120×60 cm
• 8x 200cm 20×20 extruded aluminum profiles
• Screws and assembly corners for the beams

After a quick search for the parts needed for the table and prices, I realized that it would cost way more than what I was willing to spend on it. Especially because there isn’t room for the coffee table in my workshop at the moment. Instead of buying the glass plate new from a glazier I thought about reusing it from a second hand coffee table found online. Luckily I found a table with a glass plate of the correct dimensions on DBA in a nearby city. When I got the table home I realized that it would actually be possible to reuse the entire table with glass plate and metal chassis with minor changes.

On top of the grey metal legs the plywood plate is installed and then the round tubes holding the table is just mounted on top of the wooden plate. Everything is kept in place my a threaded rod inside the round tubes. The plywood plate was prepared by cutting it to the right size, drilling holes in each corner for the threaded rod, sand it down and painting.

After this the fun part begun; playing PCB Tetris, by installing them on the wooden plate and make them fit with the least overhang and avoid empty holes in between. The available Tetris pieces was the PCBs from the PLC (the reason why I got the idea to this project), some old PC motherboards with RAM and CPU and graphic cards I had harvested from computers found lying around for bulky waste and old development boards. After playing around with different layouts I found a solution were everything fit optimal.
Instead of just being a static decoration without anything happening, I wanted the table to have some dynamic features that could be implemented sometime in the future like a spinning fan, clicking relays or blinking LEDs. That is the reason for installing the LED diagnostics panel from an old IBM server acting as a Blinkenlights. There were also room for a small LED dot matrix scrolling display. Everything should be controlled from a small ESP8266 controlled through WiFi.
At the moment only the LED matrix display is controlled through the ESP8266. The device connects to my local network through WiFi, and then the display starts to show it’s IP address. When going to this page a small web server is loaded where a message can be entered to display on the display.

A video showing the scrolling message, the table is shown without the glass plate mounted.

I’m very happy about the final design of the table, especially because I found a perfect donor table that saved me a lot of money since I didn’t had to buy the extruded aluminum profiles and the glass plate. This also greatly reduced the time I took for me to build the table.
After assembling this table I still had plenty old printed circuit boards left so I assembled another wooden plate with some of them. The purpose of this could be to make another table. If anyone is interested in buying one contact me? For now I will use the plate as a background frame when taking pictures of the different items for my retro computer collection

Indlægget The Circuit Board Coffee Table blev først udgivet på Daths Garage.