Rubik's Electronic Timer Journal
Last Updated: August 10, 2005
This journal details the history of the Rubik's timer project. Photos of the early prototypes and early tests will appear here along with explanations of what's currently going on in the Rubik's timer project.
Project History
August 10, 2005
The first complete shipment of timers and accessory kits was sent on July 27 to Kroeger, Inc., the company that runs the Rubik's website. I can't say exactly when the timers will be available for order, but it should be any day now. I had hoped to have a pre-order period, but it appears that this will not be the case. The first 20 people to buy timers will get the numbered 25th anniversary artwork logo on the puzzle pad. Having individually numbered pads printed (1/25, 2/25, etc.) is expensive and time-consuming, but I thought it made a nice way to launch the product. All subsequent purchases will have standard artwork.
Future features and enhancements will be made available as they are developed from user feedback. New features will be made available in the form of firmware upgrades that you can download to your timer through your PC computer.
This entry concludes this online journal blog, and I will start a new blog for downloadable timer firmware enhancements as the timer continues to evolve. The rubikstimer@comcast.net email address will remain the best way to obtain technical support, warranty support, and to submit feature requests. Thank you to everyone who has contributed to the initial creation of the Rubik's timer. I hope you enjoy using it as much as I enjoyed building it.
June 12, 2005
At the request of SevenTowns, I have created a small advertisement that will go on the www.rubiks.com website during the pre-order period. Seven Towns will have to review the add and there may be changes, but the following image gives you the idea (you cannot really pre-order yet like the ad says, sorry). As you can see, the enclosure is black-- I like black a lot better than they gray that I had in the first prototype. There are still four buttons-- one of the buttons is black so it is hard to make out in the photo. If you look closely, you can see the connectors for the AC adapter and the SpeedStacks port on the right side of the enclosure.
May 28, 2005
All the production parts are at their appropriate destinations, and the production circuit boards are complete (and I have a functioning sample to perform QA testing on). However, the plastic enclosure is running behind schedule. The "texturing" of the surface of the enclosure was unacceptable on the first sample, so it is being done again-- this has set the project back by a couple of weeks. Unfortunately, there is nothing to do about it at this point except wait. The color of the production enclosure is almost black, although it is actually a really, really super-dark gray (very close to black). I don't have any photos at this time, but I should have a sample within the next week (or two at the most).
From here on out, the almighty question will be "when will they be for sale on rubiks.com?" And the answer right now is hopefully pretty soon, but I don't have an exact date (Yes I realize that doesn't tell anyone anything). SevenTowns has expressed interest in taking pre-orders for a few weeks, before they are actually boxed up and shipped out. There is also the question of the limited-edition 25th anniversary puzzle-pad. I was originally going to make exactly 25 of these with the special 25th anniversary artwork (numbered 1/25, 2/25, etc). If indeed there ends up being a pre-order period, then I want to make the limited-edition artwork available to everyone who orders a timer during the pre-order period.
Here is my QA sample of a working production circuit board. CN2 and CN4 have to be manually soldered because they are for external components (battery tray and photocell sensor respectively). There are six electrical test-points, which you can see numbered TP1, TP2, ..., TP6. The electrical signal at each of these points will be tested to insure it is within specified limits.
April 3, 2005
Additional discussions have taken place with SevenTowns, and the item to report here is the sale price on the Rubik's timer. I had originally hoped to sell the timer for a small profit to keep the price low. However, it turns out that in order to sell these timers on rubiks.com, there are other parties that need to take a share in the price. This includes a royalty to SevenTowns for using the Rubik's trademark name, and a royalty to the people who run the rubiks.com website. These two royalties will account for a significant portion of the list price, so it looks like the final sale price of the timer will be closer to $100 than to $50 (which is what I had originally hoped for when I wrote the initial concept proposal document). Wow, it's been a long time since I wrote that document, and a lot has changed since then.
I hope this does not make the timer prohibitively expensive, but there is not much I can do about it. Everyone that I've spoken with has suggested that the royalty percentages are typical for a low-volume product such as the Rubik's timer.
March 6. 2005
Parts and components are now on order for the first production run; the first POs (purchase orders) have been submitted to vendors. Various components have various lead-times, the longest of which is the graphical LCD, which has a lead-time of 9-10 weeks. Assuming that nothing is wildly back-ordered and out-of-stock (and with no available substitutions), the first Rubik's timers should be ready in about 12 weeks. I don't have an exact date on when they will be available for shipment on rubiks.com; this will be worked out in the coming weeks.
An interesting question has come up in concerning the calculation of average solve-times using the time-history database. Currently, the timer does not store the cube-type with the solve-time. Therefore, when calculating a "best" average, solve-times from differing puzzles could be averaged together, which is meaningless. Of course it is possible to clear the time history whenever switching puzzle types, but that doesn't really seem like the best solution. Suggestions on the best way to handle this situation are welcome.
The following are two updated sections of note in the user manual.
Suggested Solve Initiation Protocol. If the timer is used in a situation other than casual practice, it is recommended that some basic rules of protocol be adopted to make the solving times consistent for everyone. Because the Rubik’s timer does not start until the cube is lifted from the puzzle-pad, it is obviously possible for an individual to “cheat” by turning the cube’s upper face before lifting the cube to initiate timing. At high speeds, even an impartial a judge may have difficulty determining if the solver turned the upper face before or after the cube was lifted from the puzzle-pad. This section suggests a fair solve-initiation protocol to overcome this problem.
It is recommended that everyone be required to start with their hands flat on the table (hands not touching the timer or cube). The solver must then lift his/her hands from the table and lift the cube all in one smooth continuous motion. That is, the solver may not substantially pause with his hands touching the cube or near the cube. Requiring that solve initiation be one continuous motion starting with hands on the table, makes it nearly impossible for anyone to make an upper face move before timing starts.
This same protocol will also work when pre-inspection timing is enabled. If pre-inspection is timed with the Rubik’s timer, then the competitor must: pick up and inspect the cube, put the cube back on the photocell, return his/her hands to the table, pick the cube back up-- all within the allotted pre-inspection time.
FAQ, How accurate is the timing? The photocell’s response time is approximately 15 microseconds, or 0.000015 seconds. That means that timing begins 0.000015 seconds after light hits the photocell, and timing ends 0.000015 seconds after the photocell is dark. This error is insignificant; and furthermore, these (insignificant) errors actually cancel each other out. Also, as with any timepiece, accuracy drifts as time accumulates during a single solve attempt. At 25 degrees C, the oscillator that controls the timer can have a worst-case error of approximately 30 parts-per-million (PPM). This is roughly equivalent to worst-case drift of about 0.0018 seconds per minute that that timer is running-- after 6 minutes of solving, the timer’s worst-case error reaches 1/100th of a second. This level of accuracy is typical of quartz-crystal digital stopwatches and timepieces.
February 27. 2005
I have posted a rough draft of the user manual in the download area. I am not satisfied with the photos of the LCD screens in the manual, but they are good enough for this rough draft-- you'll get the idea. The LCD is much clearer and readable than the photos in the user manual suggest. Also, there are sections of the manual that simply say "TBD" (to be done). It's an incomplete rough draft, but most of the important information is there. It should give you a really good idea of how the timer works, along with a description of all the configuration options. You can download the rough draft of the user manual in the download area. I invite constructive criticism of this user manual, but please try not to get too pedantic with grammar and spelling-- it is after all only a rough draft. :)
There is obviously debate on whether to use the timer in official competitions. As I've said before, both sides have merit. I want to make it clear to everyone that I will accept whatever the speedcubing community wants. Both the SpeedStacks timer and the Rubik's timer have flaws. Although I'd "like" to see the Rubik's timer used in official competitions, I will not lobby for this position to either SevenTowns or the Speedcubing community. Obviously, my opinion is very biased since I've put a lot of time and energy into developing the timer, so I will exempt myself from lobbying during the discussion. After reading the user manual, you will find there is enough information for the intelligent people that make up the speedcubing community to come to a plan of action regarding the disposition of the timer. If the timer ends up as nothing more than a practice tool, then I will accept this decision; if the timer is phased into use in official competitions then I will accept whatever that schedule may be.
February 20, 2005
Here are some photos of the final prototype timer in the one-piece enclosure. I assembled this unit this morning and was practicing with it this afternoon. I love using this timer! I hope you enjoy the photos. I am getting quite anxious to start production and get them up for sale on http://www.rubiks.com.
If you look closely, you can see that part of the bottom cover is missing. It was not necessary to prototype this piece since it is so simple (CNC mill time runs about $50 an hour). You can also see 3 connector holes on the right side of the timer. These are for the external power supply, remote puzzle pad, and SpeedStacks tournament display/PC computer cable.
The enclosure is made of a soft machineable plastic material-- it was milled from a large solid block of plastic using a CAD/CAM design downloaded to a CNC mill. The production enclosures will look virtually identical, although they will be cast from a much more durable urethane plastic. I am unsure if I really like this dark gray color. As always, your feedback is welcome through the Rubik's timer email.
February 19, 2005
The one piece enclosure is complete and was shown to Seven Towns Unlimited on February 18 during a demonstration in New York City. Seven Towns received the timer enthusiastically and everyone agrees on the amazing breadth of features of the new Rubik's timer over the current SpeedStacks timer features (see the journal entry for October 11, 2004 for a brief overview of the features of the new timer).
One a down note, Seven Towns is backing off on their original stance to actually use the timer in upcoming official competitions. Everyone agrees that the new timer is superior to the SpeedStacks device, and everyone agrees that eventually the new timer should replace SpeedStacks as the "official" timing device. However, there is disagreement on how long it should take to "phase in" the new timer as the "official" timing device. Some people will be happy to hear this since it can be argued that a new timer changes the timing "standard" because you don't have to slap the yellow SpeedStacks pads before & after solving, and this makes new times incompatible with old times. Other people (including myself) will be disappointed to hear this since it can be argued that the SpeedStacks timer is awkward for anyone who isn't used to practicing on it, and it adds unnecessary time to your solve time by requiring you to start and stop with your hands on the yellow pads. Opinions vary on this subject and both sides have merit. I would encourage everyone to send an email to David Jones, Chrisi Trussell, and myself with your opinions on this subject.
The one-piece enclosure is complete, however, I don't have my digital camera right now (I loaned it to a friend), so I cannot take a photo and post it. I will be assembling a complete timer with the new one-piece enclosure in the next few days and I will have my camera back by then. I should be able to post a photo in this journal within the next week.
January 17, 2005
Today I scheduled a meeting with the director of business development at Seven Towns Unlimited, Dave Jones. He is going to be in New York City on February 18, and so I am traveling to NYC to meet him there. The purpose of our meeting is demonstrate the Rubik's timer to Seven Towns so that they can approve it as the official Rubik's timing device. He will probably take a prototype timer with him back to London so that other employees at Seven Towns can examine it and provide feedback. Hopefully, they will like it!
There is not much new to report as I am still trying to get the designers to complete the one-piece enclosure prototype. It looks like the project as a whole is about a month behind schedule at this point. This is mostly due to the one-piece enclosure-- it is more geometrically complex than the two-piece design. But I think that in the end, the delay will be worth it. Almost everyone who responded with feedback indicated that they would prefer a one-piece design, and I agree that this will be for the best.
The enclosure must first be designed with CAD (computer aided design) software; this step has been completed. Now that the design is complete, manufacturing data (CNC milling data) must be set up with CAM (computer aided manufacturing) software; this step is ongoing currently. Then the CAM data is copied to a CNC mill controller where a solid block of machineable plastic is milled into an enclosure using various mill cutters. Once the prototype enclosure is complete and approved, molds are made from the prototype. Since this will be low-volume production (< 1000 pieces per year), the molds will made from a high-tech silicone rubber. To produce production enclosures, 2-part urethane plastics are mixed and poured into the silicon molds, and once hardened, the mold is split apart and a new enclosure is born.
The CNC milling data is being set up at this time. Here is a screen capture of a wire-frame model of the enclosure as the CNC CAM milling data is being created. The red represents the PCB circuit board, the purple is dimensioning data, and the black represents milling lines.
December 30. 2004
Due to overwhelming agreement from numerous responders, the Rubik's timer will be made in a one-piece enclosure. However, because a one-piece enclosure is more complicated to design and build than the two-piece enclosure, it will take longer than originally expected to make the prototype. Below you can see a rendering of the one-piece enclosure model.
To keep things moving, I plan to send the timer as it is (two-piece design) to SevenTowns for evaluation. I will also provide them with the detailed plans and the rendering of the one-piece enclosure design. This will allow SevenTowns to get the timer in their hands so they can finally use it and approve it as the official timing device for the Rubik's cube.
Here is a basic rendering of the enclosure model. As you can see, there is no ornamentation on the model-- of course the finished product will have the puzzle pad design (shown in the December 8th entry) and a couple of decals on the faceplate. Also, the enclosure is rendered in basic gray, but the finished product color has not yet been chosen. For those of you who have been following this journal, please take a moment and email me what color you'd like to see used for the base enclosure.
December 8, 2004
The prototype is fully complete and functional with the exception of the enclosure for the electronics. A photo of the prototype is shown below. As you can see, the prototype timer will come in 2 pieces: the electronics module, and the puzzle pad. When these go into production, I am uncertain as to whether I will use a 2-piece design (as shown) or i will make a 1-piece enclosure for both the electronics and the puzzle-pad. Any feedback you might have on this subject is welcome. Would you prefer a 2-piece solution (as shown) or a 1-piece unit?
Prototype photos. As you can see there is one enclosure left to build-- this last enclosure will be completed by the end of the year.
November 20, 2004
The artwork for the puzzle pad is complete. In 2005, SevenTowns is celebrating the 25th anniversary of the Rubik's cube, so I have decided to make the first 25 puzzle pads sold in 2005 contain special artwork celebrating the silver anniversary. The puzzle-pad manufacturer will silkscreen a run of 25 pieces with the artwork shown below, and then the edition will be discontinued. Starting with the 26th timer sold, standard artwork will be used.
SevenTowns has graciously provided the "Rubik's cube" logo and the "1980-2005" anniversary logo contained in the artwork below. The remainder of the clip art consists of a rendering of the 2003 world championship Toronto skyline logo (gray skyline and red arch) superimposed on a simplified rendering of the 1982 Ideal world championship logo (8 squares + globe).
25th anniversary puzzle pad artwork. Portions of this artwork are copyright SevenTowns Limited, and portions are copyright Mission Designs.
November 13, 2004
I contracted the PCB manufacturing out to a company named "ECD", which manufactures out of Mulino, Oregon USA. 2 prototype PCB boards arrived this past week, and I have soldered all the components to one of the boards. At this prototype stage, I am soldering the components manually with a temperature-controlled soldering iron. When the boards are manufactured in production runs, they will be soldered at the manufacturing company. Also, these prototypes are raw unfinished boards (to keep them relatively inexpensive-- I paid $90.00 US for these 2 prototype boards), the finished boards will have the green solder-mask and overlay applied and will be far cheaper because they will be manufactured in greater quantity..
The following photos show a populated PCB board followed by a photo of an empty board-- you can see that the layout has changed slightly since I posted the artwork in October. On the populated board, you can see the four tact switches that make up the four user buttons-- these will be capped with colored tact-switch caps. The two black connectors on the right edge of the board are the external power input and the RS-232 communications port (for SpeedStacks display and download of firmware). The 2x3 pin connector at the lower right of the board is the port through which I initially set up the microprocessor. The microprocessor itself and several other components are underneath the LCD-- this is done in order to conserve space and make the board as small as possible.
October 23, 2004
The PCB layout is complete. I have attached a couple of images below. One is a composite of all the layers of the PCB board, and the other is a shot of the primary individual layers. The CAD tool that I used to lay the PCB out seems to be having problems exporting the CAM data files that will be used to manufacture the board. I have a call into tech support for the PCB layout tool company. Hopefully I will hear back from them soon as I want to get this board into production as soon as possible.
The following shows the Rubik's timer PCB board in the CAD software layout tool:
PCBs are manufactured in layers, so the manufacturing company creates stencils of each layer that look something like this:
October 11, 2004
I realize I have not updated this journal for a while, however the project is ongoing. The firmware is now complete. I had originally planned to finish the firmware by the end of August, but I became seriously ill and was unable to work on the project for 6 weeks. I resumed working on the firmware about mid-September and it is now complete. The following paragraphs discuss the major features. A user manual will be created that discuss these items and more in much greater detail. The following paragraphs serve only to give you a general idea of the basic features available. I must say that it is really exciting for me to actually use the timer now. I have the timer attached to a mouse pad with an embedded photocell and it works beautifully. Although the timer is not in a pretty enclosure, it is completely usable and functional now.
The following photo shows the timer displaying the last solve time along with the calculated average. The text "AVG" and "SCR" identify what the 2 "soft" context-sensitive buttons do. This buttons will be positioned immediately to the right of the display. In this case, pressing "AVG" brings you to the detail average display showing the individual average times. The "SCR" button generates a random scramble sequence.
Selectable averaging mode: Off, Last, Rolling: When averaging is enabled, your current average is displayed at the bottom of the LCD. You can configure the size of the average (from 2-100, typically 10) and you can configure whether or not you want to drop the high and low times from the average. When averaging is enabled, a shortcut button is available to display the details of the current average time. The average-detail display shows each individual time and identifies the discarded high and low times (if enabled). The following capture shows some of the averaging configuration options that are available.
“Last” Average Mode: This mode averages the most recent ‘n’ times. When you solve again, the average changes to exclude the oldest time and include the new time, and so the average time changes with each solve. The average shortcut button displays the times in the last average. The following photo shows the screen displaying the individual times that make up the average, you can scroll through the list with buttons on the timer.
“Rolling” Average Mode: This mode continuously searches through the last 250 times in flash memory and finds the best average of consecutive times. After each solve, the search is repeated to insure the best average is always displayed. This allows you to cube for hours and at any time you can see where your best set of times occurred. The average shortcut button will display the details of the best average at any time.
Photocell Calibration to Ambient Light Level: The cube is defined to be ‘on the puzzle pad’ when it is within 1 cm of the pad. To make this determination accurately, there is an option to calibrate the light level at this threshold of 1 cm above the puzzle pad. For non-tournament use, this is really not necessary, and the default settings works fine in most any lighting condition.
July 31, 2004
For the past 2 weeks, I have been writing the firmware. The firmware will probably take the bulk of the month of August. During the upcoming 4 weeks, there will not be much to 'show' on this website in the form of progress. This is ironic, because the task of writing the firmware is where most of the really important work takes place. I suppose I could take a video of the LCD while using the timer as the firmware becomes more sophisticated, but it's probably not worth it. Instead, I will try to post every couple of weeks and describe the progress
The firmware is a computer program that is downloaded into the Zilog microcontroller, and it controls every aspect of the timer's operation. In the case of the Rubik's electronic timer with the graphical LCD, there is a lot of low level firmware to write before *anything* happens at all. That's because when you buy a wholesale graphical LCD from a manufacturer and hook it up to another manufacturer's microcontroller, it's not like there's a pre-made firmware library you can use to display characters. On your home computer, in one line of source code, you can write something like: printf("hello world!"); And in one fell swoop, the text appears on your computer screen. It doesn't work that way in customer firmware.
Here is a summary of the firmware I've written over the past 2 weeks. First, I wrote a set of source code that enabled the timer to turn one single pixel on and off. Once the timer could turn single pixels on and off, then I wrote another set of source code to draw a single character. This involved creating a couple of fonts. Obviously, there are no pre-made fonts for the custom LCD and the Zilog MCU. I created a miniature font management system from scratch, and rasterized a couple of fonts from scratch. Then, once the timer could draw a single specified character, I wrote another set of source code to draw words and sentences, spacing the characters at an appropriate distance apart from each other. Once the timer could draw phrases on the LCD, then I wrote another set of source code to create a very simple menu system, so the user can choose and set options in the timer. All of this minutia has kept me very busy over the past 2 weeks.
July 17, 2004
The schematic of the recently completed circuit is complete. A schematic is simply a document representing the entire circuit-- it shows all the circuit's components and connections. From this schematic, the PCB layout artwork will be generated. The PCB layout artwork is simply a drawing of the holes (to mount the components) and electrical traces (to interconnect the components). With CAD software tools, the schematic is used to verify the accuracy of the PCB traces in the PCB layout artwork. As you can see, the circuit is relatively simple, fitting on one page, containing approximately 65 components and about 60 electrically identical connection "nets".
You might take note of the component titled "CN2" in the schematic below (located at cell D-9). It represents the connector that will be used to connect the SpeedStacks large tournament display to the Rubik's electronic timer.
July 10, 2004
The breadboard prototype circuit is complete. A close-up photo is shown below with some general annotations describing the various portions of the circuit. I wanted to update the project journal so everyone can see the completed prototype circuit. This circuit will now be committed to a PCB (printed circuit board). PCB circuits are what you always see inside of electronic devices.
The power management circuit was more complicated to design than it should have been, due to anomalies with the Zilog microcontroller. Basically the entire circuit needs to be able to power on via the power button, and turn itself off via the Zilog MCU (after 15 minutes of inactivity) or via the same power button. Normally this would be very straightforward, but the Zilog I/O pins that control powering off get into a strange state when the Zilog MCU is halfway powered down and this caused the circuit to refuse to fully power down. These issues resulted in requiring a matrix of switching transistors to make the circuit stable and immune to the noise that occurs during power-down. You can see these 3 transistors and their biasing resistor network in the lower right corner. Not shown is the battery tray-- the circuit can either be powered by an A/C wall adapter (shown) or four AA batteries.
June 18, 2004
The graphical LCD display samples have finally arrived from Pacific Display, Inc.-- I feel like I've been waiting forever for these things. The photo below shows all the parts for the prototype kit.
Basically, a prototype kit consists of all the major components (excluding simple resistors and simple capacitors) to build a prototype unit. In this case, I will build the prototype on the solderless breadboard that you see here. Every part in the kit must be meticulously cataloged with a manufacturer part number and re-ordering information. This is to insure that once the prototype is built and is working, I can order the exact parts in the prototype and there are no mix-ups or substitutions for similar parts. Even though this is a very simple circuit, even the most benign-looking substitution for a very similar component can wreak havoc on the design.
June 9, 2004
Call Pacific Display and tell them to hurry up with the LCD sample! :) All the other major component samples have arrived, but the LCD was backordered until mid-June. When I get the LCD samples, I will take a photo of the pile of 'parts' and post it here.
June 1, 2004
Here is more detailed explanation of what I envision for the "strict pre-inspection mode"; please feel free to comment on it and find flaws in it, because it is something that we definitely want to get right. Please understand that these are just informal ideas that require working out or maybe even throwing out-- I do not presume to have been elected supreme rule-maker for future speed-cubing tournaments. However, the operation of this Rubik's timer will likely impact future official competitions. Your constructive feedback is appreciated so that we can work out the logistics of how the time for speed-solving a Rubik's cube will be measured.
Strict pre-inspection mode should measure the 15 second pre-inspection time, and this will hopefully eliminate the need for the judge to cover the cube before pre-inspection and between pre-inspection and solving. The judge might enable this option prior to the timer being used in a tournament. When "strict electronic mode" is enabled, something like the following sequence might occur:
1. The judge holds the scrambled cube in his/her hand until the competitor indicates he/she is ready
2. The judge puts the cube on the timer and presses the "ready/start" button, the timer starts counting down 15 seconds.
3. The competitor picks up the cube and pre-inspects
4. The competitor must touch the cube to the puzzle pad and start solving within 15 seconds or the solve is disqualified
5. Timing begins when you lift the cube from the timer in step 4.
From a competitors point of view, I imagine the judge putting the scrambled cube on the timer, and I immediately pick it up, pre-inspect, touch the cube to the pad, and then solve. My thrust is to make the logistics of competition solving operate similar to the logistics of practicing in your living room so that when facing the nerves of competition you're not doing anything unfamiliar (especially for those who can't afford their own Rubik's timer to practice all day with). The above sequence is quite similar to practicing without a timer, the exception being that you must touch the cube to the timer between pre-inspection and solving. Also, "touch the cube to the puzzle pad" means an instantaneous touch-- like a drummer hitting a drum with a stick-- you never really set the cube down. The idea is to make the transition from pre-inspection to solving as quick and natural as possible. Alternatively, someone might choose to rest the cube on the pad with both hands in position for the first moves (timing begins when you lift the cube).
The Zilog CPU and photocell can distinguish between near-dark and ambient-light in microseconds. The photocell sensor is amazingly consistent, fast, and accurate-- it is nothing like using the hand-pads on the SpeedStacks timer, which can be frustratingly inconsistent, depending on the timer. I still have memories of David Allen's near-record-breaking solve at the 2003 WC competition where the hand pads didn't register and the handheld stopwatch read 16.00 seconds (a world record) but then videotape was used to determine a slower time. Ouch, that had to hurt.
I know this is likely to be controversial. I'm sure there will be people who think competition solving ought not to work this way and there will be various reasons for it. This is not set in stone, it is only an idea and I am inviting feedback. However, before you argue a different point of view, I only ask that you try it for yourself. Put a mouse pad on the table and scramble a cube. Try pre-inspecting the cube and touching the cube to your mouse-pad between pre-inspection and solving. Then let me know what you think.
May 20, 2004
Graphical LCD Selected: It looks like the Rubik's timer will be able to generate and display scramble sequences due to the beautiful 65 x 132 graphical LCD (previously I was looking at a very simple numeric 5 digit LCD, which obviously cannot reasonably display scrambles). The new candidate graphical LCD can display graphic images and/or text in any font for which I create a pixel-map, and the cost is only an additional $2.75 per piece over what the 5-digit numeric LCD was going to cost; this will have no impact on the sale price of Rubik's timer. This is a great development for the timer because it opens up all kinds of possibilities for the built-in software (AKA firmware). The data-sheet for the new candidate LCD is in the download area. A sample piece will arrive shortly to be used in the development of the prototype Rubik's timer.
Zilog MPU Selected: A candidate Zilog MPU has been selected. It is a 20MHz MPU with 16kB of flash memory to store the firmware. After you purchase a Rubik's timer, you will be able to upgrade the firmware using your PC. This is great news because a typical ROM firmware would not allow upgrades to the software running inside the timer. A flashed firmware is upgradeable by the end-user using a PC. The data-sheet for the candidate Zilog MPU is located in the download area. A sample piece will arrive shortly to be used in the development of the prototype Rubik's timer.
Plastic Enclosure RFQs: I recently sent out several RFQs (Request For Quotes) produce the plastic enclosure. Some of the requests were for CNC machined plastic and others were for short-run thermoformed tooling for plastic injection molding. One particularly good price came back at $2700 (US) to produce aluminum alloy tooling, suitable for a lifetime of >1000 pieces (hardened steel tooling that lasts for millions of pieces is far more expensive to machine the steel mold, so this is out unless you know a million speed-cubers...).
Many thanks for all the feedback over the past week. Some great ideas have been suggested, including:
Displaying cube scramble sequences for all sizes of cubes
An option to enter "Strict Pre-inspection" mode, which also measures the 15 second inspection time.
An option to hide the solving time until the timer stops.
Displaying the rolling average time, even before "n+2" solves are reached
A note on the use of a photo-diode to sense cube presence. I have researched various means of cube detection in search of finding something that is affordable and 100% accurate. The ultimate cube sensing device would be what is known as a "capacitive proximity sensor" which actually senses the presence of non-metallic objects in the aimed direction; unfortunately they seem to cost about $50 per piece at the distributors I know of, because they're intended use is on mission-critical assembly lines where life/limb are jeopardized if it fails. Another option is a weight sensing mechanical switch. For example, the entire puzzle pad could be on a sprung platform that would depress when the weight of the cube is upon it. To engineer, test, and refine such a mechanical device using injection-molded plastic, would cost more $ than I am willing to spend on injection-mold tool design. Another option is an exposed weight-sensing mechanical switch in the center of the puzzle pad. My thoughts on this are that it would really be no more effective than the photo-diode (i.e. you have to put the cube right on top of the sensor or timing isn't halted); I also have reservations about how robust an exposed mechanical weight-sensing switch would be to repeatedly slamming cubes upon it. That leaves the photo-diode approach used in the early 80's. The photo sensor will be beneath a very small hole in 1/4" (7 mm) thick sponge-rubber. I believe it will be impossible to damage the photo-diode unless perhaps you purposefully jam the corner of a cube into the hole as hard as possible. I am also considering placing 5 photo-diodes spread around the puzzle pad, so that it's impossible to put the cube on the puzzle pad and "miss" a photo-diode. Please continue sending your comments on the cube-sensing mechanism-- it clearly is one of the most important aspects of the Rubik's timer.
May 4, 2004
The Rubik's timer project is launched due to the approval of the concept proposal document by Seven Towns Limited. Once a manufacturable and working prototype is demonstrated, Seven Towns has agreed to endorse this timer as the official Rubik's timing device. You can download the original concept proposal document here. The following artist sketch illustrates what the Rubik's timer will generally look like:
