Time Measure (Tape Measure Clock)

by scealux

61K26954

Intro: Time Measure (Tape Measure Clock)

For this project, we (Alex Fiel & Anna Lynton) took an everyday measuring tool and turned it into a clock! The original plan was to motorized an existing tape measure. In making that, we decided it'd be easier to create our own shell to go with the electronics. We motorized a tape measure and programmed it to move over the course of the day to show the time in hours (inches).

To keep the whole project looking as best it could, the largest challenge became minifying the electronics and keeping the overall footprint of the device to roughly the size of the real object.

STEP 1: Circuit & Code

The circuit is fairly simple. The attached wiring diagram lays out how the RTC Chip, H-bridge, Motor and limit switch all integrate into the circuit. The complicated part is ensuring it all fits inside the spool and surrounds the stepper motor. See the close-up picture of the spool to get a better idea of the space we're working with. For this, it was easiest to use solid core wire bent and cut to the exact length it needed to be, then hot glue it down after it was soldered together. Solder male headers to the power and ground for the board and the motor.

Upload the code to the board. The code is fully commented, explaining how the homing function works and how functions are called. Code can be found on Github gists:

https://gist.github.com/scealux/4456dedaaabe17f41e...

STEP 2: Power Supply

Next, you will need to make the power supply. We found that we could not supply consistent power by from the 12V supply split between the stepper motor and the board.

We ended up solving it by taking apart a 12V power supply and a buck converter to have a constant voltage for the Arduino and still have 12v for the stepper (Not sure it's the best way... but it worked!). Then, we ran four long wires (Vin for the stepper, Vin for the board, and ground for each to the measuring tape. Add female headers to these wire and heat shrink them together for a nicer finish!

STEP 3: 3D Printing

For the Measuring Tape:

All the files are over on Thingiverse; printed in the correct orientation, the outer case and stepper wheel should require support material. For our prints, knowing we were going to have to do post-processing either way, we printed the cases with the outsides down touching the support.

We assembled the spool by using a soldering iron to melt the component parts together. Then the ball bearings can be put in the channel of the right side body and to check how the spool rotates.

For the power supply:

Then, you can 3D print a new case for your updated power supply with the Power Supply files. We hot glued the prongs in place on the inside and then glued the two halves together.

STEP 4: Finishing & Painting

Glue the magnets into the holes on the inside of the case.

After gluing in the magnets to the holes in the case, and checking the fit, it's time to do the finishing.

When creating / finishing the case, you can really do as much or as little as you want to. For this project, we were trying to make the tape measure look as realistic as possible. To that end we spent a lot of time applying Bondo, sanding, and then repeating that process before applying the silver spraypaint. We used painters tape to mask areas we didn't want to paint and added yellow accents. You can paint the case however you want!

Using a vinyl cutter, we cut out a circular logo for the outward-facing side. Again, design the outside as you choose!

STEP 5: Putting It All Together

Put the ball bearings in the tracks on the inside of the case and insert the stepper motor with the components soldered around it. Plugin the female headers from the power supply to the male headers coming from the stepper and board.

Take the measuring tape and wrap it around the center spool. We added a piece of tape to hold on the start of it to prevent slipping. Attach the spool to the stepper motor inside of the tape measure.

Snap the two halves together and plug it in and you're good to go! As shown in the video, the tape will home and then extend to display the current time.

39 Comments

FinnishDynamite 2 years ago

Excellent !! Is there a chance to do this in metric ? And if, how can i do this ?

Alfetta159 2 years ago

Lee Valley tools likes to not just advertise but even make April Fools joke gifts. One was a story tape, a spoof of the story stick tool that some carpenters use. It's a tape that you mark up w/ your builder 'story' but it can roll back up.

The point here is that it's simply a blank tape measure so it could be marked up w/ units of time or even space-time!

- Lee Valley Tools

whoahbaby 4 years ago

Brilliant, fun, and did I say brilliant?!

CPWilliams60 4 years ago

Would have liked to be able to actually see it without getting up and looking at it. If you mounted it so the tape was flat to the wall you could see it, OR you could mount numbers on the wall so that you could see where it was pointing.....great concept, always love to see projects like this...building something out of something else. love it

Elnems 4 years ago

This is fantastic, very well done! : )

curiosity36 4 years ago

This clock project certainly measures up in a timely manner. Thanks for posting and congratulations. Kudos to you. Can you/anyone provide the part number for the H bridge chip you used?

MiroVerleysen 4 years ago

Wow very original project, keep up the good work!

pgeschwi 4 years ago

I use a micro power converter which can deliver 1A 5v from a 12V input without cooling for my projects with stepper motors.Plenty for just an Arduino even with some LEDs driven on the 5V. It has preconfigured voltage output steps and if these are not granular enough, a pot to adjust output as well. Here is a link to the Model I use:
https://www.amazon.com/gp/product/B0758ZTS61/ref=p...

distar97 4 years ago

One of the most clever concepts I’ve seen in a long time. It would be fun to add an alarm clock option.

lfoss 4 years ago

Genius! I love it!!

tfrohling 4 years ago

I'm new to 3D printing, so it would be helpful to know what type of material you used and the infill percent. Thanks very much.

andreh84 4 years ago

Nice idea :)
Like it.

warramcat 4 years ago

For a guy carrying this in his pocket it could become embarassing. Rotfl !!!! 😄

PointyOintment 4 years ago

I've been wanting to make one of these (except 24 feet instead of 24 inches, so each inch would be 5 minutes). I did some Google searching a couple of months ago and was shocked to find that nobody had made a clock based on this concept, so this is a pleasant surprise to see today :)

(Also, does anybody know where to get a tape measure that measures in decimal inches (and preferably nothing else) and is at least 24 feet long? Decimal inches would be better than the usual binary fractional ones so that 5 minutes doesn't get subdivided into quarters.)

HarveyH10 4 years ago

Decimal? That sounds like the metric system. Is there such a thing as a metric tape measure? 24 centimeters = 24 hours.You wanted feet though and 24 meters would be WAY too long. Well, just brainstorming here.


mikerockwell1975 4 years ago

Just be aware that the best standout you can buy is only 13 ft, so it'll have to point downward or have help of some kind.

PierreArch 4 years ago

Being a center driven spool, position error on 24 inches is probably not perceptible, but on 24 feet you will most likely need to compensate as the amount of tape pushed out per motor steps will decrease.

Stertheder 4 years ago

Many tapes come in Metric and Imperial, but you could get a Metric tape to have decimal devisions. But then it wouldn’t be decimal inches.

Also, if you google “Decimal Inch Tape” you’ll find what you’re looking for ^~^

https://www.mscdirect.com/product/details/51439966
Here’s one for $20. Has decimal and fractional inches.
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