Homemade Digital Gauges

[Sicofthis]

Couple of these: Thermocouple Modules and then you could use some Thermocouple pipe clamps already available on the market. These are pretty good temp sensors too: http://www.adafruit.com/products/381 Says they have ±0.5°C Accuracy but they wander a couple degrees so you have to do some averaging in your programming. And you could easily make your own clamps with them.

Thanks, that's a good idea.

I have a fluke 52II, I hardly ever use my temp probes on digi cools so, I decided not to add that fuctionality to my gauges.

Thermistors could easily be added to the existing hardware. I have plently of those if I ever decide to do that.

[IamSpartacus]

That's Pretty cool if I may say so. I need to make one of theses'.

[SAV]

Very Cool

[ICanHas]

Couple of these: Thermocouple Modules and then you could use some Thermocouple pipe clamps already available on the market. These are pretty good temp sensors too: http://www.adafruit.com/products/381 Says they have ±0.5°C Accuracy but they wander a couple degrees so you have to do some averaging in your programming. And you could easily make your own clamps with them.

Sales pitch and theory are cheap. We assume ideal conditions in classrooms to learn the theory. A simple "+/- 0.5C" can mean so many things. Some brands are a lot more conservative. China made goods not built under the same type of supervision and QC given for something like the iPhone are much more likely to be sloppy. What matters more in the real world is readout linearity over the useful temperature ranges of the sensor over the full working range of the meter and you don't want a wavy curve(10F reads 8F, 32F reads 32F, 40F reads 41F... 50F reads 49F....)

The sensor unit converts temperature or pressure into voltage... with some error. The voltmeter converts voltage into a reading with some error also. The readout accuracy is the combination of both with the display unit at temperatures between 30F to 130F. It would take a while to chill all the way to the bones to 30F but won't take long to heat up to 130F in the sun.

Two different units can perform similarly measuring the temperature of ice tea inside the air conditioned showroom but act different when you're working at 0F SST and 125F SLT with 32F meter unit temperature working on a heat pump or -20F SST and 110F SLT at 125F meter unit (roof top refrigeration unit on a hot sunny day). I swear some people really think that if you stored chocolate inside the meter, it would keep the shape after a hot work day.

When it comes to pressure gauges, most analog gauges are rated %FS while the definition of percentage is all over the map for digital ones unless explicitly said. A 2.5% 500 psi high side gauge is in specs if the reading is within +/- 12.5 psi at any point. This is a major reason why having a dedicated set of gauges for R410 is encouraged. The hashmarks become difficult to read as well as increasing the error all the way around.


That's more like the real world. Single point calibration is bull. You could adjust it to read "zero" at vacuum or atmospheric but all you're doing is shifting it resetting the zero point. There's no such thing as perfect in reality. Ideally, you start off with as little distortion as possible and use digital BSing to minimize the last remaining imperfection. "+/- 1F" could mean best accuracy centered around single point calibration at room temperature or 32F.

[maxtronics]

very good..not fine tune it and commercialize the product..it translates to a profitable business..

[TMerk]

We want to buy a digital gauge set and would like some input on the best one for around $600

[Bnmarshall]

Very nice. I love Arduino. Having a cheap micro controller for limitless projects is a game changer for home inventors.

[HHHvaz]

I love seeing Arduino projects. Nice work!

[Ryukyo2126]

whoa, cool. I just keep cigars in my otter box.

[MrMagpie]

Very cool setup!