How does the "Debt Clock" get the proper debt to display?

[Beamin]

Have you ever seen these things its a big bill board installed by some right wing person to scare people into thinking US fed debt is bad. There is one in NYC and another on your way into Boston. Maybe more. I was wondering how it actually works, do they just put in a starting number and have it increase by so much per day or is it remotely programmable, where it is told periodically so it can sync it self up. They were built before the time of wide spread cell phones, they had car and analog bag phones (3 watt cell phone would rule running 800MHz think of the range)

 

[hamster_nz]

I think that they would be more worried about political impact than accuracy... I would bet it is just an rough approximation based on trend.

Maybe a 'pager' message every now and then to sync?

Do people know what pagers are/were any more?

[CatalinaWOW]

I would bet serious money that they are just extrapolations based on the previous years data.  The real data takes a long time to come out.  I would also bet that the extrapolation is done locally, is a simple constant times time and the display is rarely updated. 

The political content of the message does not require even single digit precision, no matter which side of the debate you are on.

[amyk]

It's an approximation, but the order of magnitude and rate of change are accurate enough to get the point across.

There are also "world population clock" sites... which are much the same.

Then there's the scam sites with "X people have bought this product" counters that are clearly just randomly generated and incremented entirely by client-side JavaScript...

[ledtester]

Wikipedia says this about the first billboard:

https://en.wikipedia.org/wiki/National_Debt_Clock#First_clock

The first National Debt Clock was installed on February 20, 1989.[4] The national debt stood at US$2.7 trillion that year. The original 11-by-26-foot (3.4 m × 7.9 m) clock was constructed at a cost of $100,000.[5] It cost $500 per month[5] to maintain the display's 305 lightbulbs.[3] It was mounted on a now-demolished Durst building at Sixth Avenue near 42nd Street (a block from Times Square), facing the north side of 42nd Street and Bryant Park.[6] Built by the New York sign company Artkraft Strauss, the clock featured a dot-based segment display emulating the then-typical character resolution of 5-by-7. Similar to the second clock, the updating mechanism was such that the display was set to the estimated speed of debt growth (odometer-style) and adjusted weekly according to the latest numbers published by the United States Treasury.[5][7][8]

[nctnico]

Have you ever seen these things its a big bill board installed by some right wing person to scare people into thinking US fed debt is bad. There is one in NYC and another on your way into Boston. Maybe more. I was wondering how it actually works, do they just put in a starting number and have it increase by so much per day or is it remotely programmable, where it is told periodically so it can sync it self up. They were built before the time of wide spread cell phones, they had car and analog bag phones (3 watt cell phone would rule running 800MHz think of the range)

Well, a good old phone line and a modem will do just fine to update a number in a clock. You don't need wireless communication for that. After all the clock needs power so it takes very little effort to run a phone line in parallel.

[joseph nicholas]

The debt clock can still be seen and works.  It was moved to a dark passage around mid town NYC fromits prominent location across from Bryant Park, presumably for political reasons since NY is a solidly blue state. 

[mikerj]

installed by some right wing person to scare people into thinking US fed debt is bad.

Because everyone on the left thinks that the more debt a country has the better, right?  Or is that another stupid generalisation?

[W-B_LiteBrite]

The original debt clock's 5 x 7 dot matrix numbering appeared to have come from Time-O-Matic (known today as Watchfire Signs LLC).  They and American Sign & Indicator both lay claim to inventing the alternating time and temperature display - but that would be for another thread in this department.