I admit it: I'm a total geek. I love electronics, programming, 3D art, vintage Apple hardware, and whisky. I'm always juggling half a dozen projects. I also enjoy documenting it all: my successes, my failures, my experiences... and everything geeky along the way.

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CRT Clock, Part IV | Kevin Rye.net - Main

Kevin Rye

Geek Extraordinaire. Yeh, I said it.

CRT Clock, Part IV

OSH Park broke a record this time. They had my boards back in 8 days! Amazing. I thought I had another week to work on some code. I guess not. I'll just have to jump right into the build! Not that I mind.

CRT_Clock_PCB_assembly_0001

CRT_Clock_PCB_assembly_0002

The button board was a snap. Just 6 buttons and a header.

CRT_Clock_PCB_assembly_0003

Just as a test, I laid one of the controller board PCBs into my 3D-printed frame just for a sanity check. I was nervous that I didn't give the front header enough clearance. As I suspected, it's way too tight to get a right angle header in there. I'll have to tweak the model.

CRT_Clock_PCB_assembly_0005

In the meantime, I figured I'd go ahead with the build. I won't know for sure exactly how much space I'll need until everything is soldered together and assembled. I first need to put everything together in order to see if I need to make any last minute tweaks.

I started with the power stuff and dialed the voltage-out on the converter to 5V before soldering anything else in.

CRT_Clock_PCB_assembly_0008

Once that was good to go, I went ahead and soldered in all the necessary components for the ATmega328 and the DS3231 RTC. I then uploaded a blink sketch to make sure that it worked. All systems go. I then uploaded my preliminary TVout sketch.

CRT_Clock_PCB_assembly_0012

It was then just a matter or soldering in the resistors for the set buttons, the header, and the battery backup. This board looks really cool. If I used all SMD-components, I probably could have made this PCB half the size, but I intentionally used as many through-hole components as I could in order to match the vintage look and feel of the old CRT PCBs.

CRT_Clock_PCB_assembly_0015

I then clipped the two PCBs together. Looks good.

CRT_Clock_PCB_assembly_0004

I then chopped the top off my prototype frame in order to take a few measurements. As I suspected, the PCB and mounting holes need to be moved back a good 5 mm.

CRT_Clock_PCB_assembly_0016

In order to save myself several hours, as well as material, I only printed the portion of the frame that I needed in order to verify that I nailed the dimensions.

Screen Shot 2015-07-28 at 5.50.36 PM

I then dropped it into MatterControl and printed it out. It's perfect.

CRT_Clock_v1_final_assembly_0003

The header fits nice and snug within the cutout.

CRT_Clock_v1_final_assembly_0001

I then updated my model with the new changes and put it all back together for one last look. Solid.

Screen Shot 2015-07-28 at 7.20.18 PM

About 7 hours later, I had the final version.

CRT_Clock_v1_final_assembly_0040

Perfect.

CRT_Clock_v1_final_assembly_0061

It was time to install all the electronics. I started by soldering in the CRT connections.

CRT_Clock_v1_final_assembly_0062

I then mounted my controller PCB. It was a lot easier to do than I had imagined. Thankfully, I realized early on in the design that I'd need to put holes in the bottom of the frame so that I could get a screwdriver under the screw heads. All I needed to do was hold the nuts in place with a pair or pliers.

CRT_Clock_v1_final_assembly_0064

One thing that I didn't anticipate was that two of the screw heads might touch some of the components on the underside of the CRT PCB. I put in a few millimeters of clearance to stop that from happening, but it still looks a little too close for comfort. For now, I just slid a piece of scrap PLA in there to shield the PCB from the screw heads. When I'm all done with it, I'll just put a small sliver of black tape in there; something that won't be as visible.

CRT_Clock_v1_final_assembly_0066

Once the controller board was installed, I secured the CRT to the top with my custom pieces. I then attached the button board to the front.

CRT_Clock_v1_final_assembly_0070

It came out awesome.

CRT_Clock_v1_final_assembly_0071

The last thing to do was solder a barrel jack to the power connector. Once I put it in a case, I'll incorporate an on/off switch.

CRT_Clock_v1_final_assembly_0075

I plugged in my 12V adapter and crossed my fingers. A few seconds later, the CRT started to glow and my clock display came on screen. Awesome! I love it when everything just comes together at the end and it just works. No hacks, no head scratching, no second spins. It just works.

CRT_Clock_v1_final_assembly_0093

Although the data on screen is being pulled in from the DS3231, the code for the set buttons has not been written. I need to wrap that up and tweak the display to better center everything. I also want to put in some kind of on-the-hour animation to limit screen burn. I also have to design the laser-cut acrylic case of it.

This project involved some serious engineering, and I'm really happy with the way that it's coming out.

See this project from start to finish:
CRT Clock, Part I
CRT Clock, Part II
CRT Clock, Part III
CRT Clock, Part IV
CRT Clock Case