Bob-clock history

The history of the Bob-clock project dates back to about 1997, when I first got the idea for an alternative LED clock.

The dream

So, how did I get the idea for the Bob-clock?

Actually the inspiration came to me in a dream sometime (I think it was around 1997). This is the only time ever that I have really gotten an idea from a dream, and actually carried it out in such a physical way.

Actually the clock in my dream was not exactly like this one. As I remember it, it was a lot bigger (like 2-3 feet on each side). It was made from a brushed metal or aluminium plate, and had the 12 numbers carved out (like cut with a router) and lights behind the numbers. I don't remember if the lights behind the letters had anything to do with the displaying of the time (and if so, how the minutes were displayed), or if it had any arms. The metal plate was fixed a certain distance from the wall, without any sides, so it looked like it was hovering.

I woke up shortly after dreaming about the clock, and I guess that was when I thought that there were some great design ideas I could use. Although I am normally reluctant to copy ideas, I don't think "copying" from a dream will get me in any trouble copyright-wise etc. Actually I don't remember any other parts of the dream, like what it was about, or why there was this nice clock (c'm on, its nearly 10 years ago), but the fact is that the minute I woke up, I started considering what parts of this design I could actually implement.

Some time later my uncle Bob visited us (my aunt and uncle live in USA and come to visit this side of the family in Denmark every now and then). Since I have always had great conversations with my uncle concerning technical stuff, I decided to show him the plans I had made for the clock.

At this time I was still struggeling with the issues of using multi-colored LEDs, since these were still quite expensive. I tried thinking of a way to only use 12 multi-colored LEDS, and the rest in a single color, but this would not work, since it would be very difficult to see whether the minute arm was at 59 or 0. So I could not think of a way to make this without using 60 multi-colored LEDs.

As time passed by, I was involved in an electronics project where we needed a lot of multi-colored LEDs. I therefore spent some time finding a place where they were somewhat cheaper (especially in larger quantities), and finally ordered 200 pcs for myself. This would be enough for 3 clocks, so I started working out the other parts of the hardware. I initially considered adding a date display (perhaps something like a 2x16 char HD44780 LCD in the middle of the circle), but then decided that the design and clean look of the single circle of LEDs would be "ruined" by anything extra. Even the buttons for setting the clock were placed behind the front plate, out of sight.

This first version (v1.0 hardware) used an SGS Thomson ST6 microcontroller. I developed the code and got a demo-version running in the summer of 1998. I then took some pictures of it and decided to give these to my uncle for his birthday. I would then finish the coding and he could have the clock and bring it home with him the next time he came to Denmark. He got the clock, and has been very fond of it. I like the fact that he was the only person I discussed the design with in the beginning, and that he got the first working version of it.

For several years I had this project of making a second one for myself. I even had all the components etc., but did not get anything done.

The "order"

In 2003 I was visiting my aunt and uncle in the US. On their wall was the clock I made. My sister and her boyfriend were also visiting.

Then some time during 2004 my sister and her boyfriend announced that he had proposed, and that they were going to get married in April 2005. When their wish list for the wedding came out, they had put an "order" for a clock like the one I had made for my uncle on there. I decided that this would be a very good wedding present, and I was confident that no-one else would get one of these, since the only one in existence was the one hanging in my uncles living room (and he would not part with it).

So I started thinking about how to change the design (to avoid some of the problems I had had when designing the original version, and get a more up-to-date hardware and easier firmware development). I quickly decided to use an Atmel AVR microcontroller, which I had used for several other projects since I developed the first version with the ST6.

I decided that I would build two. One for my sister and would-be husband, and one for myself.

I also decided to put the LEDs on a circuit-board. In the original version, the LEDs were mounted in the aluminium plate and connected with a wiring harness on the back. The microcontroller and driving circuits was made on a prototyping board, and the back cover was glued on, so it was almost impossible to access the circuit.

I started out doing the schematics. After that I was ready to place the footprints. I ended up with a design consisting of a PCB of 22x22 cm, with the LEDs in the circular pattern (20 cm in diameter), and the controller and driving logic in the middle.

This was when I came up with the name Bob-clock (named after my uncle who had the first version). The new circuit design would be Bob-clock v2.0, and was very different from the first version, but the appearance on the front would be similar.

When I showed this circuit layout to a couple of students (Asbjørn and Anders) at the University, they became very interested in the idea, and wanted to have one (each) as well. So we agreed that they would get a hold of the quite large amount of PCB needed for this project. We also ordered some more multi-colored LEDs (off eBay). These were red/blue, as opposed to the red/green ones I had used in the original version. My sister and her husband would get one with the old LEDs I had left over from the first version, and the red/blue ones would be used for my own clock, as well as the two students'.

Then began the race against time to manufacture the clocks, including finishing the programming of the firmware. I actually finished the programming the day before their wedding (actually I have added more features later, but they got this version that worked for their wedding).

Making the PCBs

Creating the PCBs was a somewhat daunting task, since the board is wider than an A4 size paper (I don't know if it will fit on a letter-sized paper, which is slightly wider, but the film was not available to me in other sizes). I had to print each side in two halves and get these overlayed in the UV exposure box. It wasn't perfect, but since the traces are fairly wide, this did not pose too many problems.

When making such a big PCB (well, actually four of them), you become very aware of the hefty cost for photo PCB. The price from the supplier we used makes me wonder if we could have gotten the PCBs manufactured profesionally without paying extra (especially when you count in the work we put into manufacturing them). This would have given us the option of plated-through holes, solder-stop mask and silkscreen. But at the time we made the PCBs, this option was not considered seriously.

The two overlayed films in the exposure also created a funny little "easter-egg": I had put the print date and time on the PCB layout, and printing the two halves of the films meant that the seconds in the timestamps were different. Since they were overlayed in the exposure box, you can see two numbers on top of each other.

the PCB for the Bob-clock
the homemade PCB for Bob-clock v2.0

The image shows the finished PCB (well, the DCF-decoder was added later). The four white things in the corners are the adhesive posts that I have stuck to the back of the front-plate. Underneath them, you can see the screws that hold the PCB to the aluminium back plate (which is 22x22cm like the PCB). The thickness of the unit is about 2cm. With the front plate being larger (25cm square) than the rest of the unit, it looks like the clock is hovering out from the wall.

Bob-clock gets famous

Then in 2006 I did a write-up about the Bob-clock on Some time passed, and aparently someone found my site and posted it on the Makezine Blog.

I wasn't aware that it was posted here, but a couple of days later, a friend of mine called and said that the server I set up for him (and which was also hosting was not very responsive. Actually everything was running fine, except the Apache server, which was incredibly slow. He had tried rebooting the server, but after a few minutes it became very slow again. It turned out that the Bob-clock had been posted on Digg, and the massive amount of traffic was bogging the server down. The reason for this was, that default Apache configuration only allowed 20 simultaneous connections. So when I raised the number to 200 and restarted Apache, everything worked fine, and within the next 24 hours that single page had generated about than 2.5GB of web traffic and more than 250.000 hits.

I wonder how much the traffic had been if the server had not been busy for the first several hours after the Digg post. Once I fixed the server configuration issue the Bob-clock post was already pushed back to the 3rd or 4th page on Digg.

The Bob-clock kits

After the posts on Makezine and Digg, several persons had contacted me, either asking if I could build them a Bob-clock, or just saying that they really liked it.

In 2007 I was contacted by Ted Markson, who also liked the idea of the Bob-clock, but he actually said he wanted to build one, and if I would help him. After writing back and forth for some time, we decided to try to get PCBs manufactured, and actually sell the Bob-clock as a kit.

It was never my intention to make money off of it. If it was too expensive people could always just get their own PCBs and get the parts, but with the rather large PCB we could actually get a pretty good deal by ordering in quantity, so we would be able to sell the kits for a very resonable price. In order to make the Bob-clock more suitable for a kit, we had agreed to change it to all through-hole components. This would lower the skill level required for assembling the kit.

Ted spent a great deal of time checking component availability from various sources. Meanwhile I made quite a few changes to the circuit design, getting rid of the level translation, and adding a few options, such as an ambient light sensor and a buzzer.

Initially we aimed for getting the kits ready before Christmas. As you can tell, that didn't happen - at least not that Christmas. The project went idle for long periods, because neither of us had the time to get on with it, but occationally we would pick it up and move it another step further.

In 2009 we were finally ready to make a prototype run of the PCBs. We ordered 3 PCBs of the design (this was the v2.1 hardware). When the PCBs came in the mail, I assembled one and hacked together a firmware that would work with the updated hardware. Then I sent a PCB and parts to Ted, so he could also build one.

We now each had a working v2.1 HW, but the project was once again put on the back burner. I would occationally pick it up again and actually tinker a little with the firmware. In this process I found a few things that I wanted to change in the hardware.

In 2011 Ted asked me if there was any progress with the project, and I decided to finally sit down and make the needed updates for the v2.2 hardware design. I then sent the gerber files to Ted, who ordered the PCBs and components, and finally, on November 7th, the kits were for sale in the Lumisense web store.

The firmware i hacked together for the 2.1 HW is actually what evolved into the current firmware, and I am still in the process of merging some of the nice features that were in the 2.0 FW into the source tree.

Last updated: 2011.11.16