Here's my opinion as Chief Engineer and majority owner of a company with several products on the market.
*) Lose the solid state relays. They will surely be failed in short order the first time a service call is initiated. HVAC guys like to short low voltage wiring to look for power. Faster than getting out a meter. *) Lose the LED version. The Nixies are the hook that justifies the high price. LEDs won't. *) Not a good KickStarter project. They (the doners) tend to like big projects. Maybe one of the other crowsourced sites that cater to small projects. *) I suggest using a quick flip etch and stuff house to assemble say, 5 A/T systems and get them out there to beta testers. You MUST beta test. Our beta test policy is that the tester buys a machine at half price and when the test is over, he gets a production machine at no extra charge. Another approach is to put them out at cost. Either way you recover your costs. *) Consider putting it with SparkFun. They have three ways of selling your projects. https://learn.sparkfun.com/tutorials/how-to-sell-your-widget-on-sparkfun I have several pieces of ancillary bits and pieces that I'm about to offer. The first is a variable speed fan controller. Stick the stamp-sized board to a heat sink, connect 9 to 30 volts to the input, connect a 15 volt or higher fan to the output and viola. No noise unless it's necessary to keep the sink at the setpoint. We use this controller in our Roy induction heater so the design is well-proven. Therefore I'll probably go with option 1. *) Deal with and mock up/3d print the case first and get the approval of several women of various backgrounds. No only does the lady of the house control what goes on the furniture in many instances, they almost always control the thermostat. Figure out how you're going to manufacture your enclosure if you go the custom route. I'm very unimpressed with the appearance of 3d printed parts, even from industrial machines. I can tell you all about getting enclosures manufactured in China, for that's what we had to do to handle the cost. *) Do a "design for manufacturing" and cost reduction pass across the thing. Those Dallas temperature sensors are nice but a forward biased diode will do the same job for a tiny fraction of the cost. You can specify 4 wire telephone indoor plant wiring for the hookup and do a Kelvin measurement to eliminate lead resistance effects. Up until a couple of years ago I was seeing thermistors in extremely cheap consumer goods. Now I see diodes. *) Get hold of an ASHRAE handbook and learn how to properly implement the outdoor temperature modulated algorithm. Hint: Torrent :-) *) Also study the ASHRAE standard comfort map. This maps temperature vs humidity vs comfort. The aim of your thermostat is not to control temperature but to control comfort. *) To that end, you need a humidity sensor so you can properly implement the comfort algorithm. *) You need outputs for de- and humidifiers for the same reason. Particularly central humidifiers in the winter. One can maintain comfort at a much lower temperature if the humidity is kept high which will save the owner a lot in energy costs. Here's a concrete example. Right now to keep my honey comfortable, the house is at 79 degrees and 20% RH. I'm about to re-install the water-line-connected humidifier in my propane furnace. (I take it out during the summer to prevent lint build-up). I know that with 50% humidity, she's comfortable at 69 deg. Major savings in fuel. *) contemplate the liability you're taking on. A malfunction could start a fire or let a house freeze up and burst pipes. At least get a personal liability rider on your homeowner's policy. A megabuck's worth of coverage is very cheap. *) Consider your engineering approach, particularly your software approach. Are you building self-checking and redundancy and other high reliability techniques into your code? Using the Arduino black box library doesn't give me fuzzy feelings in this area. *) If you're going to make these in commercial quantities, consider getting it listed. We work with ETL (I have a grudge against UL and their nasty politics). Figure at least $5 large. Well, that turned into an epistle! Just some things to think about, though. John On 01/02/2016 09:38 PM, Joe Croft wrote: > Happy New Year Yall!! > > To open this new years, I have been continuing on my saga with the > NixieStat Thermostat. I have a hackaday project with pictures and more here: > > https://hackaday.io/project/4452-nixiestat > > I want to make this a kit, either both a Nixie tube version as well as 7 > segment LED version. Unfortunately I don't have the cash on hand to do > this in any quantity to start so I was thinking of turning to Kickstarter. > The question is, what is the quantity of kits I should aim for? If I do 50 > or each kit the approximate prices would be $115.00 for the LED version and > $155.00 for the Nixie tube version (darned in17 are expensive!). > > So the question is: Is one hundred kits to many or too few? > > Looking forward to hear from yall. Thanks! > > Joe > -- John DeArmond Tellico Plains, Occupied TN http://www.tnduction.com <-- THE source for induction heaters http://www.neon-john.com <-- email from here http://www.johndearmond.com <-- Best damned Blog on the net https://www.etsy.com/shop/BarbraJoanOriginals <-- Affordable Fine Art Originals PGP key: wwwkeys.pgp.net: BCB68D77 -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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