The (long) story of the relay clock - Page 1
Forum section: electronics / projects

author: Spemo
author_rank: Regular Contributor
timestamp: July 25, 2019, 10:20:36 pm
content: Hello everyone,in this thread I want to share the (long) story of the relay clock, how it came to be, the problems and what's going on today.But first things first.One day, I stumbled across a video made by look mum no computer titled "Retro Russian "NIXIE" VFD Clock ELEKTRONIKA 7" where he shows a russian clock and asked the question: But what does it sound like?Well the answer was: like nothing. Silent. And that gave me an idea. Why don't I come up with a way to make a clock, which is "electronic", but sounds like it's doing something?Since I liked electronics and a challenge, and had nothing better to do, it sounded like a good idea to keep my mind busy.With that in mind, I started thinking about the idea. Which parts to use, how to make it, prices of everything, should the parts do the thinking oder use an IC and just let it pretend like it's doing something?After a week or so I had my answers: relays (I like the noise they make), they should do the "thinking"(counting), they will be cheap shitty parts from china (somehow I ended up with "recycled" relays) and with actually making it - It'll work out somehow.So I started to look for programs to design the circuit and the PCB, I ended up with Blackboard Circuit designer and a circuit simulator made by some guy named falstad I think.It took me 4 weeks to figure everything out. I had some basic knowledge, but I have never made up something this big and this complex, all I've ever made never contained more than 5 active electronic parts.so here is what was needed:First off, I figured I'd make it with decimal counters. So in total, it needed 6 counting modules to get the time format HH/MM/SS, and each one has to trigger the next one once it reaches 0(zero) again.To make this work, I somehow came up with 2 relays per digit, with a delay circuit between them. So when the first one is activated, the other one activates a bit later.I figured out that the delay was the key thing to make everything function, everything I tried before just triggered all the relays at once.this is what the first working circuit looked like in Blackboard:The IC sockets are connected to work with these relays:So I tested this in a smaller way and it worked, kinda sort of.Next thing: well ok, now you figured out how to make the counters, but you still need to get this to a readable format - the outputs of the counters had to be translated for a 7-segment display.That alone took another week, and here is what I came up with:In total around 350 diodes or something like that.So I went onto ebay and started looking for the cheapest parts I could get.Here is the list of components that were needed:I think 102 Relays (came from ebay, cheapest ones were around 3€ for 10 Pcs)102 IC sockets for the relaysabout 55 NPN Transistors (again, ebay)55 or so Capacitors (I had enough overkill 2200µF 25V ones somewhere)55 trimpots500 diodes500 LEDs555 and support components for timingloads of wiresand PCBs (perfboard). With these I ordered the largest ones I could get for reasonable money, so I ended up with 30x18cm ones.After everything arrived, I put it all together. Very quickly I realized that I forgot to add a reset circuit, which resets the Hours when it reached 24 hours.also, after noticing that the LEDs I ordered are very bright, I had to somehow get the brighness down...which I somehow managed with a PNP transistor.After many errors and mistakes, and my basic soldering skills, I managed to get it to work and this is what it looked like:it was huge. 30x18cm PCBs, and 4 boards in depth, it wasn't easy to find a place to put it. Also, I quickly made a housing for it, since it was very sensitive to movement (soldering skills.....)after that, I noticed that with the best "tuning" it was never able to keep time properly - some googling later I found out that ne 555, resistors and capacitos shift in value with temperatureSo I looked for a simple 1 hz generating circuit, found one with a crystal, adapted it to the existing circuitry - and there came PCB number 5 with better controls for everything.After all, this monster of a clock worked fine for about 3 Months or so, but it had its issues.1. even with the crystal, timekeeping became more and more of an issue.2. Somehow, it sometimes went mad and one counter module decided to erraticly stop somewhere inbetween and messed everything up.3. the reset circuit had a mind of its own, sometimes it simply resets the way it was supposed to or startet "flickering", and finally managing the reset after 10 or so attempts.4. The display. Either due to my poor soldering, or due to very badly made LEDs, a lot of them failed sadly. Also, it was still very bright and able to light up a room.5. Power consumption and distribution. In the end this thing took a lot of power- about 15 Watts at full brightness - 10 at a more humane not sun-like experience setting. but still, a lot of power, which hat to go everywhere. it came to a point where I doubled every powerline in the circuit.6. Size. Size. Size. It was just too big. The final dimensions were 35cm wide, 23cm high, 25 cm deep.This is the story of the first relay clock that I made, and let me tell you, there were a lot of headaches with this one.There is video of this on youtube, if you want you can check it out here:That's all for the first one, I have made some more to try and improve the circuit and everything else. I will show you the others too.enjoy your day,Daniel

author: Spemo
author_rank: Regular Contributor
timestamp: July 25, 2019, 11:10:44 pm
content: So, the 3 Months it worked I got more and more fed up with it, it was sitting on my bench for reapair more than it was working and displaying the time.So I got to work to figure something out.My goal was to make it smaller, and a bit easier on the wallet for me (The original cost me around 75€ including the case).after 3 "revisions" of the original circuit, lots of rearranging the parts and testing, some "revisions not working(I was trying to get rid of some relays), I finally I had something I was happy to try and build.To keep everything in order, I called it CV4 (circuit version 4).So this is what I came up with:The idea was, to put everything onto small 5x7cm perfboards and glueing t hem together afterwards.It was supposed to make throubleshooting and replacing non functional pars a lot easier (which it didn't).This approach meant, that there would be a lot more wires, and due to spacing problems, I was stuck with the 555 again for timekeeping.This is what it looked like :The first finished and working parts:Signal Converterfinished without display frontfinished backsideComplete with case:With this approach I managed to get one thing done - it wasn't that big anymore.But it had loard of other problems this time.With this many wires connecting everything together, failure was normal. It was as sensitive to movement as the original one - so no change there.The glued together PCBs didn't look very nice.and again, the 555....Power consumption was down a bit, but with the same massive superbright sunlight feeling eye-burning display, there was no hope.I added some features to this, like a better brighness control. but overall, the same story as before. Fragile and unreliable. So I had to make another one.......quickly.

author: Spemo
author_rank: Regular Contributor
timestamp: July 25, 2019, 11:23:34 pm
content: After some time and 2 more "revisions" of the circuit, CV6 was made. I went back to the 30x18cm PCBs, now packing everything onto a single board.The idea with this one was, to have a small basic display on the main board, and replaceable otherones to plug in.Also, the display got it's own "powersupply" with a transistor for every element.Another addition was an auto dimming function, to reduce the brightness automaticly at night, with a setting for 20:00 or 22:00,, and automatic full brightness at 6 in the morning.And it got some paint, but see for yourself:The removable Display:FrontsideBackside almost finishedWith this one, it finally looked like I found a good compromise with everything.It looked nice, worked as it should (mostly) and finally kept the time, it was off a minute after a week, I was happy with that.It wasn't flawless though.The removable display decided to break, I tried to remove it and all the solder pads came off, it was hopeless after that.the new "powersupply" for the display was very sensitive to creeping voltages, getting all the contacts isolated from each other was impossible, so I gave up and bridged the transistors.The built in display wasn't perfect either, again with those cheap white LEDs I had left over from the original clock....the crystal circuit (let's call it clock generator) was still on a seperate board.And then, with the attempt to make it more modular, and with my stubborn head refusing to finally use proper (and thicker) wires came the cable mess, which had it's own problems like the others before.But it worked, and I knew, the next CV only needs a little bit of tweaking.....at least it looked nice for once

author: Spemo
author_rank: Regular Contributor
timestamp: July 25, 2019, 11:39:01 pm
content: So, after a while I decided to finally order another set of 110 relays for a second one of the clocks - and started to build CV7.It finally ironed out all the problems I had with the previous versions, runs reliable and got some nice new features.A small overview:- Mainboard has no display built in - small modular display units, easy to replace, easy to remake- fading LEDs - looks a lot smoother- night mode now turns off blinking leds and the module for displaying seconds- removed the option of setting the night mode time- Crystal clock generator now on mainboard- simplified wireing on the backside- lower power consumption (5 watts at full brightness)- simplified the way of setting the time (only 2 buttons)- rearranged componet layout for easier wireing- new brightness dimming circuittake a look:front sideback sidein case (in night mode)This one has proven to be the most reliable yet - no failed leds, no hiccups, nothing. And I really like the fading display, I will make a short clip of this soon.The only thing it still has is that it's still pretty large, like a big picture you hang on the wall.The next step is to make it more compact, to fit into smaller spaces.Also, an alarmclock would be nice aswell.... all I can say is, CV8 is built in blackboard, I'm just waiting for parts.....we'll see.that's it for now.have a nice dayDaniel

author: digsys
author_rank: Unknown
timestamp: July 26, 2019, 12:17:59 am
content: I applaud your effort .. but you're definitely crazy :-) Do you intend to make a proper PCB at any stage? Have you considered adding other mechanical noises / circuits for a more "varied" tune? Wondering if the same repeated relay "click" would get boring?

author: Spemo
author_rank: Regular Contributor
timestamp: July 26, 2019, 12:34:41 am
content: Quote from: digsys on July 26, 2019, 12:17:59 amThank youI have considered the proper pcb - but since the relays are so tightly packed, there would be little to no benefit to this.The noise changes a bit with temperature, and since the components are not matched to each other, each digit sounds different.Oh, anf after a while, you get used to the noise....

author: digsys
author_rank: Unknown
timestamp: July 26, 2019, 12:49:46 am
content: It will be interesting to hear it when you post the clip.

author: james_s
author_rank: Super Contributor
timestamp: July 26, 2019, 01:00:46 am
content: The benefit would be reliability and ease of servicing, also it would make it far easier for someone else to duplicate the project. It's definitely cool but you have to be a masochist to wire so much stuff up by hand. A modular design with PCBs that plug together and no rats nest of wires would solve most of your problems. Also using a 555 as a timebase is hopeless, you'd never be able to get an accurate enough oscillator, that's not what that IC is designed for.

author: digsys
author_rank: Unknown
timestamp: July 26, 2019, 01:40:09 am
content: Quote from: james_sThose were my thoughts ... for the clock, it could be a plug-in, and let the user decide the accuracy, if he wanted to make a more accurate one

author: rs20
author_rank: Super Contributor
timestamp: July 26, 2019, 01:55:41 am
content: Quote from: Spemo on July 26, 2019, 12:34:41 amQuote from: Spemo on July 26, 2019, 12:34:41 amClearly you don't value free time very highly?But seriously though, very impressive project.

author: Spemo
author_rank: Regular Contributor
timestamp: July 26, 2019, 06:18:47 am
content: sure, ease of servicing is the other thing.Honestly, I don't know how to design a proper PCB, and also, I don't know if it would work out - I'm sure I'd still have to solder in a huge amount of jumpers ....look at how bad the wires cross each otherI'm don't know how to route this onto a PCB.I have a huge schematic for this - maybe someone can walk me through this?And the thing with the free time - well sure it takes up a lot of time to wire this all up - but that was the goal, to keep me busyThank you for the nice comments, I'm happy that you guys like it

author: digsys
author_rank: Unknown
timestamp: July 26, 2019, 06:42:22 am
content: Can you post a link to the schematic, and give part# details of the relays / components used? Maybe someone can help

author: rs20
author_rank: Super Contributor
timestamp: July 26, 2019, 08:43:33 am
content: Quote from: Spemo on July 26, 2019, 06:18:47 amSo don't let me tell you how to live your life, I'm just foolin' around. But if I wanted to do something like this, this is one of those situations where autorouters* would be great. The clock speeds are low so there's really no such thing as a "poor PCB layout".So I'd capture the design in KiCad (or, if I already had the schematic like you, just use the corresponding netlist I suppose), lay out the components in the PCB editor, and then figure out how to use an autorouter (either the one in KiCad or some third party situation.)You'd be surprised at the complex connectivity you can achieve with a 4- or even 2-layer PCB, especially when the relays you're using have such an incredibly huge pin pitch compared to modern components.Having said all that though, this is probably not the best "Learning how to make PCBs 101" project. At all. You'd want to gain experience doing a simple, 2-relay, manually routed board first just so that you're not completely confounded when dealing with hundreds of parts.* A feature of PCB tools which lets you place all the components wherever you like, and it figures out how to lay out all the traces for you. Also, a feature which is widely maligned as cheap way out, although I think there are still niche situations where they are applicable.

author: Henrik_V
author_rank: Regular Contributor
timestamp: July 26, 2019, 01:26:49 pm
content: A trick I was told by the son of Konrad Zuse (Build the first relay computer Z3) that his father used to extend relay contact livetime (at that time) and bouncing contact problems:He tried to switch as much relays as possible without power at the contacts.

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 26, 2019, 01:59:37 pm
content: When I see such a complex project completed and operational, all I can say is: "I am not worthy of tying your shoe laces!"Seriously, my sincerest congratulations and respects.One comment about your video: it seems that there are sudden brightness jumps on the LEDs. Having attempted to video record LED displays, I know that sometimes the camera's auto-exposure function gets confused by the extreme contrast and will cause this.Are the brightness jumps real, or is it a camera exposure artifact?

author: edavid
author_rank: Super Contributor
timestamp: July 26, 2019, 02:25:28 pm
content: Hey OP, how about posting schematics of your counter circuits?I think I would have been tempted to start with a regular MCU based clock and add some software controlled relays as noisemakers - but I'm lazy.

author: JVR
author_rank: Regular Contributor
timestamp: July 26, 2019, 02:28:19 pm
content: Damn. I wish I had the time to do this kind of stuff. Well done on getting that ratsnest to operate, even if it was a little flaky in the first revisions.

author: SiliconWizard
author_rank: Super Contributor
timestamp: July 26, 2019, 02:34:20 pm
content: Given there would be so many ways to get the same result and appearance, or pretty similar, with much simpler appraoches, I'm baffled how the OP got the courage and patience to do this.

author: Spemo
author_rank: Regular Contributor
timestamp: July 26, 2019, 05:05:30 pm
content: Hey,Schematics will be posted - once I'm done remaking then - to maybe make them more understandable. I hope I have it done this night.Quote from: schmitt trigger on July 26, 2019, 01:59:37 pmThank you!The brightness jumps are intentional - they are different brightness settings. This got removed in later versions.I don't have problems with exposure there - the bench is extremely well lit, one day I found some LED panels with 512 high power SMD LEDs... at the moment I have 6 of them lighting up everything, 2 additional smaller lights (40 watts each) in the background. powerconsumption for all of this: 420 WattsBut it's the only way to get my phone to shoot some usable footage.

author: Spemo
author_rank: Regular Contributor
timestamp: July 26, 2019, 07:27:31 pm
content: As promised, here is the "Schematic" I use to build this monster - maybe one of you can find some use with this.Have a nice dayDaniel

author: HB9EVI
author_rank: Frequent Contributor
timestamp: July 26, 2019, 07:54:57 pm
content: remembers me a bit my Z80 board with all that wild wiring, but it's still small compared to your clock.I guess I can imagine the thrill letting the idea for it grow in your mind and make it real, step by step, although I wouldn't do it myself - at least not a rather trivial thing like a clock - like already said by someone else: too lazy for it; I appreciate a RTC in an STM32 with a small TFT - but I admit - there's no challenge down that road.

author: iMo
author_rank: Super Contributor
timestamp: July 26, 2019, 08:07:35 pm
content: Fantastic project!!PS: do you plan a wrist version of the relay watch?

author: Spemo
author_rank: Regular Contributor
timestamp: July 26, 2019, 08:11:24 pm
content: Quote from: imo on July 26, 2019, 08:07:35 pmsure, why not!3 Kilograms in weight, 50000mAh Batterypack to get through the day, and a massive 35x22cm case on your arm, does that sound ok for you?Price would be 1599,99$...you know, because of the wrist strap.

author: rs20
author_rank: Super Contributor
timestamp: July 27, 2019, 08:10:04 am
content: What program did you do the schematic in?

author: German_EE
author_rank: Super Contributor
timestamp: July 27, 2019, 08:12:25 am
content: You're crazy, but it's a nice kind of crazy that happens to engineers when they get an itch that needs scratching. One question though, where did you get those large sheets of perfboard?

author: Spemo
author_rank: Regular Contributor
timestamp: July 27, 2019, 08:40:28 am
content: Quote from: rs20 on July 27, 2019, 08:10:04 amI made this in Blackboard Circuit Designer. It has all the parts needed for this project.http://synthbu.de/blackboard/I don't know how to set the language though. I've read on a forum somewhere that it can be set to english, or it does it by itselfQuote from: German_EE on July 27, 2019, 08:12:25 amI got them off Ebay, there is one seller who sells them at a reasonable price, around 15€ for 5 of them. They come straight from China, sadly they are a little bent, but properly mounted it works ok.Just search for 18x30cm PCB and set it to world wide search.

author: edavid
author_rank: Super Contributor
timestamp: July 27, 2019, 05:36:51 pm
content: Quote from: Spemo on July 26, 2019, 07:27:31 pmThat is a "pictorial diagram" rather than a schematic. Is it possible to create a schematic?

author: TomS_
author_rank: Frequent Contributor
timestamp: July 27, 2019, 06:54:56 pm
content: Welcome to the crazy clock club.Here's mine: ornotblog.blogspot.com😁

author: Spemo
author_rank: Regular Contributor
timestamp: July 27, 2019, 08:35:38 pm
content: Quote from: edavid on July 27, 2019, 05:36:51 pmsomething like this?

author: rstofer
author_rank: Super Contributor
timestamp: July 27, 2019, 09:40:08 pm
content: That's some nice work. You clearly have more patience than I.

author: edavid
author_rank: Super Contributor
timestamp: July 27, 2019, 09:51:13 pm
content: Quote from: Spemo on July 27, 2019, 08:35:38 pmYes, exactly, although it turned out to be only slightly more comprehensible than the pictorialsThanks...

author: Spemo
author_rank: Regular Contributor
timestamp: July 27, 2019, 10:08:00 pm
content: QuoteWell here you go, I drew something up in tinyCad with the right values. I did this quickly, so this is only the 3 digit version with startup circuit.

author: edavid
author_rank: Super Contributor
timestamp: July 27, 2019, 11:04:46 pm
content: Thanks, much easier to understand!

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: July 28, 2019, 12:51:25 am
content: Now a really crazy idea would be to make a "digital" clock without any semiconductors. Use a mechanical pendulum for timing, relays for counting, and small incandescent lightbulbs. I wonder if such a thing was ever made during the early electric era.I find it curious that most popular wrist watches use the opposite approach now, a quartz oscillator but mechanical hands. They have never appealed to me.

author: texaspyro
author_rank: Super Contributor
timestamp: July 28, 2019, 04:06:57 am
content: Quote from: maxwell3e10 on July 28, 2019, 12:51:25 amI've seen a digital clock where all the counting, display, etc was done with neon lamps.

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: July 28, 2019, 04:30:40 am
content: Yes, I guess I've come across these projects too, using a Dekatron or just individual neon tubes as gates. But that is very advanced 20th century technology:) Using relays, incandescent lamps and a pendulum one can stay entirely in the 19th century.

author: Spemo
author_rank: Regular Contributor
timestamp: July 28, 2019, 07:30:44 am
content: Quote from: maxwell3e10 on July 28, 2019, 12:51:25 amIt is possible, I have a "pictorial diagram" for this, but it would double the amount of relays. Capacitors are a must though.Then you can definately say it's a rats nest of wires.Oh, and accuracy would be hard to get aswell

author: texaspyro
author_rank: Super Contributor
timestamp: July 28, 2019, 07:33:54 am
content: Quote from: Spemo on July 28, 2019, 07:30:44 amNo relays or transistors were in the neon clock...

author: Spemo
author_rank: Regular Contributor
timestamp: July 28, 2019, 07:41:54 am
content: QuoteOk, but I think that would require high voltage, and I don't want to go there honestly....Quote from: maxwell3e10 on July 28, 2019, 12:51:25 amThis is what I meant would be possible

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: July 28, 2019, 02:39:34 pm
content: Here is one approach using just relays and resistors to build a counter.https://www.ee.ryerson.ca/~phiscock/papers/relay-counter.pdf

author: macboy
author_rank: Super Contributor
timestamp: July 29, 2019, 08:29:04 pm
content: The high power consumption and the fading/failing LEDs is caused by not having current limiting resistors on the LEDs. You are directly driving them from the power supply, which is a bad idea. LEDs designed to be driven directly by 5 V or 12 V are avaialble (with built in current limiting resistors) but I don't think that's what you are using.

author: Spemo
author_rank: Regular Contributor
timestamp: July 29, 2019, 09:34:49 pm
content: Quote from: macboy on July 29, 2019, 08:29:04 pmthey all have current limiting resistors - the values of the resistors are calculated to run them at around 10-15mA per LED(don't remember exactly). They can handle 20mA without a problem, but I don't want to run them that hard.

author: Spemo
author_rank: Regular Contributor
timestamp: July 29, 2019, 11:12:43 pm
content: Hey everyone....Since I still have to wait atleast a week to get all the parts for CV8, I decided to build another CV7....I don't know why, but I guess I don't have anything else to do....This time I'd like to show you step by step, and also keep track of the time spent building this thing, since I have no idea how long it really takes.So lets start.The first thing that had to be done was to modify standard 16pin IC-Sockets by removing not needed connections.I decided to put all the relays back into sockets, since the relays do fail some day, and also, because I went the cheap way, I ordered the cheapest and got relays that have been desoldered somewhere.They are chinese relays either way (new or not, named HK19-F), I have no idea how old they are and how many cycles they went through. Desoldering them when they fail is a huge pain and also ruins the copper pads on the perfboard. So sockets it is, not as stable, but easy to service.So, they had to be soldered onto the Perfboard:Modifying, soldering and aligning them to sit straight took about 3 hours.Then, the transistors for the counter modules had to be soldered in:The resistors and capacitors followed:The not so nice soldering ( I have shaky hands, so this is as good as it gets):and at last for today, all the flyback diodes:Total time spent building this so far: 6 Hours.Now, I'm not rushing this build, in my experience, doing this quickly ends up in a lot of errors and mistakes. So we'll see how long this takes.If you have any questions, fell free to ask them.Have a nice dayDaniel

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 30, 2019, 04:07:44 pm
content: Quote from: Spemo on July 29, 2019, 11:12:43 pmSage words. Rushing any project, specially a complex one like this, is a certain recipe for disaster.Emphasis is mine.

author: Spemo
author_rank: Regular Contributor
timestamp: July 30, 2019, 08:35:29 pm
content: Hello again,today I carried on with the build of CV7#2.first, the power and ground lines were soldered in.Then, the output posts were put in.after that, the connections from the transistors to the relays were made, then the connections from the top row of the relays to the bottom.The next step is already prepared, I had to cut 44 short wires. They will mostly complete the counting modules, but you'll see.Time spent for the progress today : 3 hoursTotal time spent building this: 9 hourshavea nice dayDaniel

author: Spemo
author_rank: Regular Contributor
timestamp: August 10, 2019, 09:39:40 pm
content: Hello again!A few days ago the last missing parts for CV8 finally arrived. So I decided to stop working on CV7 #2 and start CV8.all the counter modules on CV7#2 are done and tested, they work fine.One day I'll finish it, or maybe inbetween, I don't know yet. When it's done, I'll see what to do with it, since I have to order a complete set of relays for it, and proper (ebay) ones that have unmodified leads are around 50 - 60€ for the 110 or so needed, Maybe I'll keep it as a spare, or maybe someone wants it when it's finished. Who knows.So I've started with CV8.The background story:Since the CV7 is still kind of big, and is more something you hang on a wall like a picture, I wanted to find a way to make it more compact. Now I knew I couldn't keep the depth the same, but atleast it could sit on a shelf, as long as there is an outlet nearby.Also, the idea of making an alarm clock out of it was wandering around in my mind. I know how I'd have to do it from the electric side of things, but I don't know how to fit it into the very limited space I allow the clock to have. So we'll see.Long bla bla short: more compact, but basicly same circuit.But some changes had to be made.The first thing I came up with was something I have used with the first version - multiple boards. In the PCB "design" program I managed to fit everything onto 3 PCS including the display.The PCBs are the cheapo ones from ebay 10x22cm.Here is the layout:To make everything fit and to keep the displayboard clean, I had to do some changes and some stuff had to go.First thing that I decided to do was to put all the capacitors on the backside of the PCBs.Then, the display had to sacrifice some stuff. It will not have 7 segment displays for the seconds, it will have some simple LEDs connected directly to the outputs of the counter modules. This saves a lot of wires, diodes and space on the PCBs.The rest will be pretty much the same.So I've been working on this for the evenings now, total time spent is 14 hours so far.I guess this version is as small as it will go, the only thing I could change would be the capacitors, so they can fit between the relays. But for that I have to go lower in capacity and higher with resistance, and I haven't had the time, motivation or all parts to test it out.Here's my progress:Have a nice dayDaniel

author: Spemo
author_rank: Regular Contributor
timestamp: August 11, 2019, 10:14:39 pm
content: Hello everyone,a little update.Today I was able to finish the first of the three PCBs and test it. Thankfully, and for the first time ever, everything worked right away.Looks like I finally found the right way to wire this up.Doing all of this in this compact way does come with drawbacks though. Everything takes twice as long, and the limited space makes it very hard to fit and route everything, without it getting out of control.This "rats nest" turned out to be the most challeging so far, since I have to consider every direction of the wires twice.Also, I started the second PCB.as always, some Pictures of the progress:Time spent today: 4 hoursTotal time: 18 hours.Have a nice dayDaniel

author: Spemo
author_rank: Regular Contributor
timestamp: August 20, 2019, 12:02:23 pm
content: Hello again, another little update.Some progress has been made, and a few mistakes aswell. Also, I realized there are some problems.So here we go!I finished up the second board, but I could't figure out how to wire up the signal converter diodes without everything getting super thick.So I went the easy (or lazy...) way and decided to put that on another board, but then make it as flat as possible. Board 2 now has the DC-DC converter on it.So it will have 4 boards in the end.Here are some pictures:But I got tired of soldering for now, and, as someone mentioned, a proper PCB would be better. So I forced myself to learn something new (expressPCB plus) to design a proper PCB. Then I found JLCPCB, noticed that I can't upload the files of that program since it doesn't export any gerber files. so I had to learn to use KiCAD. I hope I figured it out, I will order some test PCBs soon.The worst thing of all this is that I have to "translate" my complete "pictorial diagram" into KiCAD. I've been working on that for 6 hours, the counter modules are in and the display, but nothing else.Also, which is new to me, I will use a 2 layer board.The size of it is already known, but it's a large board (282x356mm) and for 5 PCBs JLCPCB charges 55€ + 17€ shipping. So it is quite expensive, but I guess if I calculate all the wires and solder and everything else, it doesn't look as bad.Maybe more layers can fix it, but since I can't change the size of the relays it won't go under 200x300. and the price at 4 layers is still the same, but makes it much more complicated.so the price for one complete build would be:15€ per PCB30€ for 110 used/recycled china relays3€ for 100 capacitors3€ for the diodes3€ for resistors4€ for 200 NPN , and 50 PNP transistorsaround 7€ for the timing circuit1€ for 10 NE555and depending on what you want 5€ for the display LEDs.Total cost: 71€.That all depends on what the current pricing on ebay is and how much you already have.Have a nice day,Daniel

author: Spemo
author_rank: Regular Contributor
timestamp: August 24, 2019, 11:34:18 am
content: Hello again,as promised, a small video where you can hear what the relay clock sounds like.Every version sounds similar to this one.Also, since I really got fed up with hand wireing this thing, I ditched the signal converter and decided to make a simple display directly from the outputs of the counter modules. I'll put some caps over the LEDs with numbers on it to see what time it is.This version also showed the limitation of hand wireing and perfboard, and I've decided that this will be the last hand wired relay clock I'll make (at least for a while).I learned to use KiCad and discovered JLCPCB, so a proper PCB is coming for this.I have two designs, one single board and one multiboard solution, almost completed.But, as everything has a colst, both options are expensive for me. The single board would cost me around 65€ for 5 PCBs, the multiboard around 50€ for 5 sets of 3 PCBs.If I wanted to build 5 complete clocks (multiboard) I'd be at 231€ with "recycled" relays. A lot of money which I can't spend right now, but I will eventually.Have a nice dayDaniel

author: Spemo
author_rank: Regular Contributor
timestamp: December 19, 2019, 09:06:53 pm
content: Hello again!After almost 4 months of nothing, I finally managed to throw some money at this project and get some PCBs ordered and assembled.This is CV15, which will hopefully be the last version for now.Of course, the PCBs didn't come without some mistakes, but nothing too serious and I was able to fix everything.But from the beginning.In a local shop, I found some nice wooden boxes and decided to make the PCBs fit in them, with the relays that I already had.Unfortunately, the shop stopped selling them, shortly after I placed my PCB order - bummer.Oh well. then I tested all the relays I had, since I baught them used, I thought that would be a good idea. of all 220 I had, about 15 had weak coils.So in the last minute, I decided to order IC sockets to put those relays in there, since they will fail eventually. This also meant, that the whole assembly wouldn't fit in the small wooden box anymore, so I now have to make my own one.While assembling and testing, I found out that I forgot some traces in the design process, which called for some bodge wires, nothing wild.Also, the inputs of the display PCBs were in the wrong order. Took me almost an hour to figure that out.Also, some of the solder pads were too close together for my liking.Other than that, within the first 30 minutes of it finally running, another relay went weak and had to be replaced, at this moment I was very thankful for the (quite expensive) sockets I put in.Conclusion:- total cost of ~100€ including shipping and import taxes for 5 sets of PCBs and some parts, without relays.-some issues, but fixable. the next PCB order would be without those problems.-It's time to finally admit to buying new relays, not used ones. sure, they are at 0,20€ each, but the failure rate is quite high.- I have to find another housing for it, or make my own one.Other than that, time will tell how well it goes.This is as compact as it gets with these relays.As always, here are some Pictures.Have a nice dayDaniel

author: schmitt trigger
author_rank: Super Contributor
timestamp: December 20, 2019, 04:27:52 pm
content: I have said it earlier, but will say it again:Magnificent project. I wish I had 1/100 the patience you have.

author: Spemo
author_rank: Regular Contributor
timestamp: December 20, 2019, 05:54:17 pm
content: Quote from: schmitt trigger on December 20, 2019, 04:27:52 pmThank you very much. It sure was a long way, but atleast I feel comfortable about giving these someone else, if anyone wants one (who knows).

author: digsys
author_rank: Unknown
timestamp: December 20, 2019, 09:45:11 pm
content: Boards came up nice, especially with the black resist. Are you doing a final video with the sound?

author: Cerebus
author_rank: Super Contributor
timestamp: December 20, 2019, 11:06:26 pm
content: Quote from: Spemo on July 26, 2019, 08:11:24 pmAt least it'd be a bit lighter than this wristwatch, though perhaps not quite as accurate.

author: Spemo
author_rank: Regular Contributor
timestamp: December 21, 2019, 08:54:46 am
content: Quote from: digsys on December 20, 2019, 09:45:11 pmYes, once I have made a case for it I will make a video with sound.Quote from: Cerebus on December 20, 2019, 11:06:26 pmYep

author: george.r
author_rank: Contributor
timestamp: December 23, 2019, 06:23:16 am
content: Brilliant project, and commendable dedication.Great to see the learning curve here

author: Spemo
author_rank: Regular Contributor
timestamp: January 04, 2020, 08:34:10 pm
content: Hey everyone,I had some time making a short video of the latest version.Check it out:Have a nice dayDaniel

author: DaJMasta
author_rank: Super Contributor
timestamp: January 04, 2020, 09:16:40 pm
content: Have you run into any reliability issues in all your versions? Had any relays wear out?At a cycle per second, I suppose it would take a while, but I'd assume in the long term, the relay(s) switching the flashing dot would be the first to go, since they're switching 60 times for every minute hand switch. If you end up doing another version some time, you could use two relays to switch each flashing dot, SPDT or similar where one input for each relay is high and one is low. Then if you had a pair of LEDs in opposite polarities between the two relays, you could drive each relay half as many times per minute, so long as they are offset in phase by 90 degrees, and get the dot to light whenever one relay is connected to power and one to ground.Anyways, with the lifetime of a relay and a one cycle per second switching, it may be entirely unnecessary. Neat project with a very satisfying sound!

author: Spemo
author_rank: Regular Contributor
timestamp: January 04, 2020, 09:46:33 pm
content: Quote from: DaJMasta on January 04, 2020, 09:16:40 pmYes, I have run into reliability issues with the hand wired designs, and everytime I had the relays in regular IC sockets on the hand wired ones. They often lost contact because the perfboards were quite flexible.Also, if you look at earlier posts in this thread, you see how much wireing is needed to make one of these work - something has to fail at that point.with the relays, I purchased used relays from ebay at 0,20€/piece, so I don't know how long they will last - some have failed already, some came unuseable right away. You pay cheap you get cheap.as for getting the 1Hz signal and the blinking dot:to get these clocks somewhat accurate, I have to use a crystal and some ICs, they put out a 1Hz signal with 50% duty cycle, the blinking dot is connected to that output through a transistor(so no problems there). But, the counter modules require a duty cycle of 15 to 20% (on time), so there is a circuit with 2 relays converting that.It works like this:The first relay is turned on by the output of the ICs, shortly after that, the second relay turns on and breaks the connection between the first relay and the IC. With the other set of contacts of the first relay and a power connection the short pulses for the counter modules are created.So every seconds 2 relays turn on, which would obviously fail first.I am not worried about contact failures inside the relays, since they only have to switch about 100- 200mA, which is 5 to 10% of their maximum rating. So either the coils go weak or the mechanical parts fail.If I find a way to replace this duty cycle converting circuit with something, I might do it - but that would also mean it loses some of the ticking noise. It's what you hear most of the time.

author: Prehistoricman
author_rank: Regular Contributor
timestamp: January 04, 2020, 10:13:14 pm
content: You are nuts! I thought it was crazy when I made an EEPROM programmer on perfboard that has 30-40 wires.I watched the video and you have the worse case of European number 1s I've ever seen. It's like an M got cut in half.Anyway they're very cool. The night dimming function is great. I like the orange LED one.Does it make much more sound when the hours turn over?Why do you use so many relays? 4 7-segment displays and 1 segment for the seconds surely means you only need 29?

author: Spemo
author_rank: Regular Contributor
timestamp: January 04, 2020, 11:22:31 pm
content: Quote from: Prehistoricman on January 04, 2020, 10:13:14 pmHey, that thing with the number 1 : look closely, number one is just a simple / , the other thing is a 7I use this many relays because this clock uses decimal counters - so:10 digits for 10 seconds (=20 relays + 2 to carry over to the next module)6 digits for the tens of seconds (=12 + 2 relays)10 digits for 10 minutes (20 + 2)6 digits for minutes (12+2)10 digits for 10 hours (20+2)and 3 for hours (=6 relays)In this version I just have no 7 segment displays for the seconds - the circuit still has to be there though. The relays are doing the counting.Startup: 2 relays1Hz signal: 2 relays24 Hours reset: 3 relaysauto dimming at 20:00 : 2 relaysTotal: 109 relaysThe more it has to turn over at once the louder it gets, so turnover from 19:59 to 20:00 is where you get the most noise. it has to turn over all the modules plus the dimming circuit.Have a nice dayDaniel

author: Prehistoricman
author_rank: Regular Contributor
timestamp: January 04, 2020, 11:40:33 pm
content: Quote from: Spemo on January 04, 2020, 11:22:31 pmNo, on your handwriting on the underside of the orange LED clock.I didn't understand that you used relays for counting rather than only switching the LEDs. That makes a lot of sense actually.