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Ha! HT is in use… how about that? Where did you find a list of those?
(Yes, sorry for the HT -> MT substitution.)Some more suggestions:SS, for single-stroke1S, for single stroke (surely this isn’t taken?)Can I ask why “cocoa”? That is also the name of one of the major MacOS frameworks ( https://en.wikipedia.org/wiki/Cocoa_(API) ), and I’m concerned that it could lead to confusion.
If the name is just because it’s evocative of the name Hershey, we might consider a few alternatives, for example cacao, choco, etc. However, I would instead suggest the prefix “HT” — for Hershey Text. Many font families have similar name conventions, where a 2-3 letter prefix or suffix designates the origin (font foundry), as in “Trebuchet MS” or “URW Venus (see https://www.fonts.com/support/faq/lt-mt-ef-abbreviations and http://blog.extensis.com/fonts/abbreviations-font-names.php ). I think that “MT Bird,” “MT Pancakes”, and “MT Little Princess” would be compact, easy to read, and clear that they represent a family (or shared origin, at least). Thoughts?
Great– we’ll follow up there.
Then it sounds like you’ll need a driver board swap. Please contact us directly (by e-mail or through the contact form at http://shop.evilmadscientist.com/contact ) to arrange that.
I don’t see anything obviously wrong from the photo.
My next question would have been whether you were getting an error (or just not machine response) but since you don’t see it in the list, I would presume that you are getting a “no connection” type error.The most likely causes at this point are that the USB cable is bad, or that the USB connector on the circuit board is bad. Do you have another USB cable handy that you could try testing with?If you plug in only the USB cable (not the power cable), do you get any lights on the EBB?
Can you please clarify what you mean by “only powered on”?
So that LED can handle up to 350 mA, running at about 3.5 V. If you’re running from a car, that probably means 12 V power. To run the Larson Scanner PCB from that you would need to use a voltage regulator, perhaps a 7805 to reduce the 12 V to 5 V.
For the LEDs, you will need 9 transistors, each wired up like those in the first illustration (“Transistor switch”) here:
https://learn.sparkfun.com/tutorials/transistors/applications-i-switches
Each transistor requires there to be two resistors: R1 (the “base resistor”) that goes between your microcontroller output and the base of the transistor, and R2 (the “load resistor”) that goes between the 12 V power supply and the LED, attached to the collector of the transistor.A good, cheap, and tough transistor that you could use would be the TIP31– about $5 for 10 of them.
With the current that you’ll be using, that transistor can give a gain factor out of about 100. So, to get 350 mA of collector current through the transistor, you will need about 35 mA out of the microcontroller outputs. If you’re driving the Larson Scanner at 5 V, and each of its outputs goes to the base resistor, then you’ll get about 4.5 V out of the microcontroller outputs. The base-emitter connection of the transistor takes about 7 V, leaving about 3.8 V. To get 35 mA at 3.8 V, you need the base resistor to be about 100 ohms.
Now for the load resistor. With 12 V in, 3.5 V taken by the LED, and only about 0.1 V taken by the TIP31 collector-emitter voltage, that leaves about 8.4 V. To drop 8.4 V at 350 mA, you’ll need a resistor of about 24 ohms. No problem there. However, its power dissipation is a concern: P = I * V, or 350 mA * 8.4 V = 2.94 W of power to dissipate. I’d recommend using at least a 5 W resistor for each of these.
If you can figure out _exactly_ which LED you’re looking at, and what power supply you’ll be using, I can help recommend transistors and resistors.
It’s not designed for high power LEDs, but if you really want to go MUCH brighter, you could always use the outputs to drive transistors that control higher output LEDs instead. Do you have a particular LED in mind that you would like to use?
No, they are by design set up so that the mode cannot change except by interacting with each board individually. However, you can override this by wiring up all of the buttons in parallel, such that pressing the button on one board does trigger the change on all of them. We know of a few people who have set up their displays this way.
Yup! That looks fine (and huge)!
I like the idea of creating a font table like this, but I would recommend having only a single line in the drop-down menu to select it. Perhaps that should be something like “Generate font table from this text.”
I have not seen that kind of ghosting before. That sounds like there’s a significant problem. Is this a relatively new clock, or has it been around for a while? It is potentially possible that some kind of gradual LED failure could lead to this… maybe try swapping the LED digits around to see if that changes anything? A poor connection to the drive transistor or LED driver chips could potentially cause a problem like this.
For the losing seconds problem, are you using the Chronodot? If so, you should still expect a time drift of around two minutes per year, or about 10 seconds per month. If you’re seeing significantly more than that, your Chronodot may not be working (or connected) correctly. A first test is to reset the power, and see if it “remembers” the time.Once again, these look really great!
I think that I’d be OK with extending the format to allow floats directly– seems that there shouldn’t be any technical reason why we shouldn’t do that.Glad you found the SPUD. :)
