How to Build a Word Clock: A Look at Tulip’s Latest Demo App

It can be difficult to explain a SaaS Operations Platform to people.

In many ways, platforms are best explained through hands-on experience, not verbally. So we spent a lot of time thinking about how to get people to understand exactly what Tulip does in a single experience.

What we landed on was a manual-assembly experience where people build their own word clock from start to finish.

What this meant, in practice, is that we needed to build that work clock from scratch, in house. So here’s how we designed the product behind our latest demo.

A word clock is just what it sounds like. It’s a clock that tells time by spelling out the time in script rather than by the classic dial design or with digital numbers.

We created this word clock as a way to demonstrate multiple different facets of Tulip – smart work instructions, device integrations, IoT connectivity, and analytics. A participant gets to see everything that sets Tulip apart in one demo.

In the demo, each potential customer assembles their own word clock. As they do so, they experience everything a factory operator would, and, in the process, they see the power and flexibility of Tulip. In the end, participants get to keep the final word clock as a gift.

Building the word clock was an exercise in engineering, design, and manufacturing. We wanted an aesthetic object that cost less than $10 for everything – all electrical and mechanical parts, a power supply, and a box.

What do you need to build a word clock?

What do you need for a working word clock? Here’s a quick inventory:

1. A face plate with letter cut-outs to show the time
2. 2. A diffuser for the LEDs so that the light has an even distribution. If you didn’t use a diffuser, you would likely be able to see the LEDs through each letter.
3. A case or a different way to hold each of the components together.
4. A 3D honeycomb grid to prevent light leakage from each of the LEDs. Without this, if you lit up a single LED, the light would bleed into the other letters. This would make reading the clock impossible
5. Electronics – 64 LEDs at least for an 8×8 clock and a microcontroller to drive it all
6. A way to keep time that is more accurate than a microcontroller.
7. The code that will make the microcontroller run as a word clock.

That is seven distinct components, each with their own unique challenges.

Turns out designing a word clock is easier planned than done. Here are some of the ways this task got complicated.

Iterating to a final design

Most word clocks use a laser-cut piece of metal or wood as a face plate to block the light. In searching through word clock designs, I came across some designs that used a bank printed circuit board (PCB) as both the faceplate and the diffuser of light. The silk screen and copper had been added in the negative of the letters and with a thin enough PCB, the light was able to shine through as a diffuser.

These features solved three of our problems:

1. In designing a face plate, we got two of the other components for free
2. We didn’t need to add a diffuser since the PCB acted as a diffuser and a face plate
3. 2. We didn’t need to add a case because we could mechanically attach the back plate with electronics to the face plate

With most of the mechanical issues resolved – we needed one more thing: the honeycomb. I had our application engineer extraordinaire Justin help create a quick design in Onshape which we printed one of the Formlabs Form2 3d printers we have in our labs. We found that printing directly onto the build plate created the least amount of distortion. We were iteratively able to decide on the tolerances and create a design that fit nicely.

Since we had decided to forgo a case, we knew we shouldn’t put any electrical components on the back. This was partly for safety (we didn’t want people accidentally touching the back and shorting two things) and partly an aesthetic choice. This meant everything had to fit on the board – including the ATMega microcontroller.

If you have any questions about what this looks like under the hood, check out our Github!

For the electrical design and software – I forked a different design that used an ATmega328 (the same chip as an Arduino) and a pre-made LED block. We were able to use most of the forked code (with some minor updates to refresh-rate and letter placement). I updated the schematic and decided to do the layout in Eagle, instead of Altium, so the design would be more open-source friendly.

We added an additional feature: a Real Time Clock (RTC) and battery module that would keep the time even when the device was not powered. Often when your microwave or stove loses electrical power, the clock will be reset. This is because it doesn’t have an RTC with a battery. These little modules came with a battery and solved a bunch of design problems with respect to batteries. We program these clocks to the current time using Tulip and a serial protocol (i2c) that we connect directly to our Gateway.

With all of the seven requisite parts working, we were able to finalize the design for the complete word clock.

Sourcing the components & Mass Production

In school or as an engineer this is where the process ends – you’ve made the design and it looks good. For me, finalizing the design was only half of the process – we still needed to productize. This meant finding someone to make sourcing enough components for 500 Word Clocks – this meant 500 ATMega328s 31500 LEDs, and 4000 resistors as well as many other components.

Since we work with Contract Manufacturers for our main hardware products (Light Kit and Gateway), we were able to use these relationships during the prototyping and mass production phase. For more complicated mechanical projects, this is where productizing hardware fails – finding a manufacturer to create quality parts is difficult. Luckily because of our established relationships and the maturity of electronics assembly in China, we were able to navigate mass production with relative ease.

Sourcing the components was harder since we were very price sensitive. We didn’t want to use our typical process and have our contract manufacturer to purchase parts on our behalf. We also didn’t want to use American distributors like Digikey or Mouser because they are high-priced and require import into China

Since the BOM was small and most of the components were commodities, I did the sourcing myself. We leveraged a Chinese distributor, LCSC, for most of our parts. The parts are dirt cheap and if you pay for the fast shipping, they arrive in about the same time as North American distributors. For our key components: the LEDs and the Microcontroller we stuck with American distributors.

After resolving sourcing and getting all the parts to the factory, we were able to smoothly move into mass production and received 500 unassembled.

Here’s a quick breakdown of the word clock app in practice.

1.) Pick-to-Lights guide operators to the RTC module bin

2.) Program the RTC

3.) Pick the baseplate and spacer

4.) Attach the RTC

5.) Complete the Assembly and plug in the clock

6.) QA the Word Clock in Line

7.) Complete Assembly!

If you want to build a word clock yourself and see what Tulip is all about, visit us at one of our upcoming shows, or schedule a demo today.