It’s that time of year in both hemispheres — time to get outside and play before it gets unbearably hot (or cold). No matter what your game, don’t keep score in your head or with piles of rocks — make yourself a portable, fold-able scoreboard like [LordGuilly] did and be on the bleeding edge of display technology. It’s really more roll-able than fold-able, which is awesome because you get to unfurl it like a boss.
All you need is a place to hang it up and you’re good to go. This thing runs on a beefy 10,000 mAH USB power bank, and [LordGuilly] says that it’s easy to read even on really sunny days. As you may have guessed, those are WS2812 strips and they are set into rectangular PVC bars. The bars are set equidistant from each other in a frame made from modified version of cable tracks — plastic chain links for cable management.
Good looks aside, we especially like that there are two controller options here. If you want to assign a dedicated scorekeeper, there’s a handled version that uses an STM32 blue pill and is wired to the display. But if you’re short on people, use the ESP8266 version and update the score with the accompanying app. Check out the demo after the break so you can see it in action.
We’ve seen a few scoreboards over the years, including this beauty that’s meant for indoor games.
Super cool. I think it would be more readable, though, with the addition of a piece of black cloth behind it.
I agree.
When my daughter was in youth soccer (especially 3rd-5th grade) a portable scoreboard would have been nice.
But since most games were in bright sunlight, and LED display would not have worked.
As I put in the post, I used in several soccer (football, as it was in England!) games, and even in sunny days, visibility was good. It’s true the sun in England is not particularly bright :-)
And the setup was done in a way to enhance the contrast, used hang it from a chair, not facing the sun, and placing a dark jacket behind if needed
Try something like this:
https://hackaday.io/project/161215-largemechanical-hand-activated-7-segment-display
Kids love to make the numbers turn, and it takes no power and there is almost nothing to go wrong. Oh, and it is really inexpensive to make.
“It’s true the sun in England is not particularly bright :-) “…. One “son” in particular but now he’s over here…. 😁… Just kidding….
What kind of nonsense is “10,000 mAH USB power bank” anyhow? What the heck is wrong with calling it “10 AH”? (and then you won’t get in the holy war of what a comma means). And what does “mAH” even mean in the context of something that should be measured in WH?
But it’s fake anyway! You cannot expect to pull (say) 1 amp for 10 hours out of such a thing. The marketers likely added up the (inflated and optimistic) mAH ratings for the cells, rounded up, and stamped that on the product blurb. After the boost to USB 5V, you’ll be doing well to get just 5 AH = 25 watt-hours out of it.
The one exception I’ve seen to this foolishness is for the larger packs, which actually do quote capacity in WH, and are careful to be just under the 100 WH airline carry-on limit, stating (e.g.) “99.16 WH” (in the case of may RAVPower Extreme).
Other than outright frauds, the worst offender I’ve seen is a “12V” 3-cell Lipo pack commonly seen on the usual deal sites: billed as “12 V, 8000 mAH”, it’s actually three 2.6 AH cells in series (adding up to “8000 mAH). The actual capacity is more like 22 WH: 2 Ah at 11 V.
But anyway: on this build, how about layer of black rip-stop behind the LEDs? Negligible weight, would boost the conspicuity.
I’d say it is a contextual thing. The primary market for those battery banks are phones. For most phone batteries the manufacturer reports it as mAh, and that is what the average consumer has a good context of. Plus those batteries are all single cells so reporting watt hour doesn’t seem relevant or needed. Those battery packs provide a regulated output anyway so what’s the point of using Watt hours?
Watt/hour for batteries always sort of screw me up because how do you calculate something like that with a changing voltage? Sure my cell is nominal at 3.7 volts and has a capacity of 1Ah, but does that mean I have 3.7W/h of storage? It’s fully charged at 4.2 volts so does that mean it actually has 4.2W/h of storage?
To calculate the real watt-hour value with a changing voltage you should integrate the instantaneous current times voltage over time giving you a good measure of the amount of energy extracted from the cell. This value would also only be valid for a specific discharge current, as the cells have some internal resistance and other weird chemical stuff. I wouldn’t expect any manufacturers of consumer products to go to such lengths though.
As to which measure is more useful would – it depends on how you are responding to changes in voltage. If you have a linear regulator feeding from the battery, then the actual voltage is not very interesting (as long as it’s high enough) and simple amp-hours is what you want.
If you are using a DC-DC converter of any kind, then the battery current will change inversely with the voltage, so the watt-hour measure is more useful. The same applies to driving a motor if your driver is smart enough to ramp up the current when the voltage drops. I think it’s a safe to assume that most devices using lithium packs fall into this category.
Also, to nitpick, it’s watt-hour (equal to 1W * 1 hour = 3600J), not watt/hour (some suspicious unit).
The dishonesty in this is that all of these packs rate themselves according to the batteries alone. You put four 2.5 A*hr batteries in parallel and call it a 10 A*hr battery pack. (Or 10,000 mA*hr, because a really big number sells better.) None of these is rated on output, and since they use boost converters to get to 5V, even if they were 100% efficient, the output current would be less than the input current. So yeah, it’s like the “instantaneous peak power” ratings on audio amplifiers back in the 1970s, except that they don’t even bother to make a distinction between battery capacity and output yield. But we live in an age of “alternate facts”, so what else can we expect?
Where do they claim that the pack outputs a particular mA x h? They’re selling batteries, so they list the capacity of the batteries. How miserable do you need to be to take issue with that?
Here’s how miserable: I take them at their word. They are not selling batteries. Their devices contain batteries, but they do not give you direct access to those batteries. All you have access to is the 5V output, which will NOT deliver 10 A*hr. It’s like saying that a particular engine is rated at 500 hp, because that is how much power there is in the fuel it consumes, even if it can only deliver 100 hp to the wheels. Miserable enough for you?
No, the dishonesty in this is that the battery capacities are outright lies. Like politician-sized lies.
I’m sure you can get properly rated battery packs somewhere, but with most brands being relabelled Chinese cells, the actual ratings are far lower than the absurd claims. (See also: Chinese LED lumen ratings)
Unfortunately, many high street brand rechargeable batteries are similarly nowhere near claimed performance in real-world applications.
The 10,000 mAh is even more fake, as power bank manufacturers list the battery capacity, not the real output. That number is usually for 3.7V, you will get nothing near that at the 5V output (it’s usually listed, around 7Ah in the one I have).
But it’s the way these products are defined, and if I ask someone with little technical background to get a 5V 7 Ah USB power bank, they will struggle to find it
This is awesome ! Cornhole, horseshoes, whatever the backyard game this is a great addition. It doesn’t matter if it’s powered by a hamster running in a wheel….. this should take care of scoring. I agree… a piece of black cloth would improve it. Also… can it be decremented ? It never fails that the point gets posted to the wrong team. Needs to be able to downcount one side and upcount the correct side.
yes, there is a way to decrease, I didn’t put it in the video. Colours can be changed while it’s “0 0”, once at least a goal is scored, the button will decrease the instead of changing colours
Very nice !
thanks for the post, glad you like it!
What’s the dominant WS2812 failure mode? If one dies, is it normally the LED portion or is the data path broken which would bork the remainder of the row or possibly the remainder of the screen?
The LEDs are chained, so one failling would affect whatever is after it in the screen. But I don’t know what are the possible problems of the an individual WS2812 failling, I’d assume it will stop forwarding data, so it will kill the remainder of the screen
The individual failure mode really is the big question.
Answering my own question: the 2812 and 2812B are apparently susceptible to a single-pixel failure. The 2813 has a bypass which allows it to tolerate non-adjacent failures.
Visually, the 2813 (and the higher-voltage 2815) have four connections between adjacent pixels rather than three.
not sure if a bypass will help, as it might actually ruin the aspect ratio. If one LED is busted, you likely need to replace the whole row anyway