Hi Rob, East Coast, USA... been to the other Cambridge... very different!

Hi guys and thanks for the responses!

I had no issues with turning these big numbers into ints or longs, but floats kept being unhappy. One workaround is to simply scale the number up (factor 1,000,000,000), turn it into a long, then do a long/long division with a float cast in front. Works like a charm. Of course, the only reason I get away with this kludge is that I know the numbers being scales to be less than 1. Thus, I do not exceed the allowable range for a long.

Nick Gammon adapted an excellent library to allow the Arduino to break the shackles of large numbers. I happen to find the library super useful for things like solving quadratic equations with large numbers. However, I wonder how I can turn the output from the sub-routine (three floats that Nicks library calculates correctly) into standard floats. Similarly, if I want to use a byte as a multiplier in a BigNumber-based calculation, is there a way to cast that?

I have been very happy with my thermocouple (TC), though it is not sheathed inside a probe - the weld is exposed. For your application, a sheathed TC might make more sense (i.e. a stainless steel tube with TC inside) because it's easily cleanable. Besides a higher cost, the other downside of a sheathed TC is the longer time constant re: temperature. However, for your application, you should be fine.

Omega sells lots of stainless-clad TC's and I'd be surprised if E-bay doesn't feature them also. I have no need for food grade safety, as my TC is being used strictly to make printed circuit board assemblies (i.e. mounting surface-mount chips on them). That TC is affixed inside the oven on a PCB so it's time constant is also longer, but hopefully analogous to the time constant of the solder pads on a PCB inside the oven. So far, I have had great success.

0.1 uF capacitor from analog in to GND to cut down in noise.

Over sampling followed by decimation (ie right shifting the summed results of a couple hundred reads by 7 bits, for example)

Using a comparator to create a cleaner on/off transition

There is no need for the cap you mention - PicoUPS offer a 1.2A charger / switchover board at the low end and higher capacity boards as well to take care of the UPS part. Instead of a lossy diode or other approaches, they use MOSFETs that act very quickly. Read up on the info they have on the site, I was impressed.

The PicoUPS power supplies have wide DC input ranges and plug directly into a standard motherboard plug. So, I am not sure what you need other than to figure out the peak loads, the required components and a credit card... 

I would focus on the end power needed. In the case of a server, you're typically looking at 12VDC for the HDD's and 5VDC for the board. PicoUPS offers all sorts of pre-confectioned power supplies that are DC-DC solutions with very high efficiencies. Makes much more sense to go directly DC-DC with a switch mode than the AC intermediary steps. What's great about the PicoUPS products is that they're based on ITX and ATX power supplies that plug directly into existing motherboards.

I took apart a similar UPS and saw the same inductors you mentioned, so I believe you are not looking at a transformer. Large inductors used to smooth out the output from a UPS to be more sinusoidal. I took apart a variable-speed drive system for a condenser system and found an inductor big enough to put a major dent in the floor.

My APC UPS failed on account of a fried battery pack, not a unusual issue with a SLA battery. I pulled the thing apart and the main OEM PCB filled the length and height of the device. I bought a new set of batteries and am planning on using a picoUPS to provide the charging and switchover, while a board of my own design uses the dimension engineering switch mode power supplies to provide 5VDC for a USB charger and 6.5VDC power supply for our portable phone base station. The external power supply will be switch-mode as well (15VDC @ 1.2A).

I figure my "solution" to be significantly more efficient for my purposes than the OEM solution - i.e. charging a USB device and the main phone base station for the house. Even with a negligible load, the OEM solution lasted less than an hour. I expect the new one to last for hours instead since we'd be looking at a 75-85% conversion efficiency and without the intermediate DC-AC-DC steps.

[wedding fund]

This is but the beginning. You may remember a comment in the past about weddings being perfect time sinks, i.e. whatever available time you have will be sucked up, and spent. Best of luck with it all, and thanks again for making such an awesome piece of code that does what it says and perfectly.

FWIW, I am switching to the Teensy 3 (i.e ARM) platform for some of my boards, I presume that Easytransfer should compile just fine on the Teensy 3?

And if it doesn't, can I send you one? These are extremely nifty little platforms.

PS: Donated to your beer errr... wedding fund. That's right, it was the wedding fund.

All I can say is that the SIM900 shield from SEEEED works great. Why keep waiting when there are quad-band alternatives out there that will work pretty much world-wide?

Hey guys,

You're likely aware but I thought I'd show you some interesting behavior in your authentication system. Specifically, a Italian user logged in and then assumed my identity. See here http://arduino.cc/forum/index.php/topic,137092.0.html

He apparently did not try to do this, the forum server did it automatically for him. Can you guys look into it?

Oi!

Ciao Ragazzi... come al solito ho fatto il login e mi dice che sono loggato come Constantin -.-
Ed è già la seconda volta che mi logga con l'utente sbagliato.

FWIW, I had a order with OSH Park turn out great, another order vanished. Since Laen never contacted me, I never got to pay and hence the board was never produced. When I brought it up at a later time, he apologized and told me that he'd come up with a better order documentation system that wasn't as prone to fail silently.

But, given the limitations of the fab that Laen uses, I prefer iTead - smaller vias, tighter allowances. Boards that can be made by iTead have to be redesigned for Dorkbot. The dark purple color is cool, the gold surface coating is a nice touch, but ultimately, most of us are primarily after getting their boards turned quickly and hence a consistent process is a big plus.

SmeezeKitty, do as you wish.

All I can tell you is that I had to replace every rubber hose on a diesel engine because some lugnut sprayed them with the same 'Perkins blue' as the rest of the engine. And to do that, we got to lift the engine out of the boat, drain it of all fluids, etc. Not the fastest fix.

Every hose had cracked thanks to this painting treatment. Given how important belts are, I wouldn't mess with them and pick up the desired signal elsewhere.