5 Channel Thermocouple Gauge/Amp w Analog Out & More

[loxxrider]

(see additional reply on previous page)

I don't have any worthwhile pictures to show as examples, but the vems lcd (something I can offer to match if you don't mind the size) is 96x60 overall (including its required circuit board).

The smaller LCDs I want to offer are called dogm163 and dogm204. They are 66x40 for the 4 line version and 55x31 for the 3 line,both including the circuit board. So we're talking almost half the size of the vems board in a dimensions for the 3 liner.

Again, I can match the vems lcd also if you already have one. Just let me know what you want and I can do it. I'll just have to figure out a way to mount buttons for both displays.

Woukd you want the buttons on the display or on the box where the thermocouple amps live?

[loxxrider]

Oh and the cool thing about the small displays is that they're German made! Your Audi will thank you

[PRY4SNO]

The more I think about it, being able to blend output from Vems and the TC amp on a single screen (and the option to stream to a tablet via Bluetooth) would be awesome. Definitely want the audible alarm for if I'm not watching the gauge and the car goes out of range. My personal preference is colour matched with the OEM gauges.

[loxxrider]

Ok, if you want to be able to have it all on one screen then you have two choices.

Either you send the thermocouple analog signals to VEMS (you'd just buy the $60 5 channel TC amp) and handle everything through VEMS. I'm not familiar enough with how the VEMS LCDs code works to tell you how to do that. The problem with that is that you don't get color matched screen in that case (you need a microcontroller to do that). Also, there aren't currently enough inputs on VEMS to take all the thermocouples (at leat not with the way most of us use VEMS.

So that brings me to the second option which involves my microcontroller. It would probably be too complicated for me to intercept the signals from VEMS's LCD output and handle it through my controller. I'm sure it's possible, but I'm not sure if I want to get into that. So the other option would be to essentially have a switch that you could use to switch between the VEMS data and data from the thermocouples. That would just require some fancy cabling. It's not my focus at the moment but I do think it can be done and I will keep it in mind as I continue on with this.

The third option is Bluetooth, but that's a whole 'nother can of worms. I have looked into it and it will be possible but I have to watch put for the scope creep. I need to focus on one thing at a time at the moment!

[alxdgr8]

You'd probably do well with something like this after you have the car tuned then if you don't want to monitor all 5.

http://thesensorconnection.com/egt-probe-thermocouples/instrumentation/meters/superlite_egt_meter.shtml

I've got the same gauge for a wideband in my 90q, except from Auber Instruments. Their EGT kit comes with the probe for a few bucks more than sensor connection sells just the gauge for http://www.auberins.com/index.php?main_ ... cts_id=230

[loxxrider]

Yeah, I forgot to mention that that one is available on eBay for a lot cheaper. However, you do get what you pay for when it comes to thermocouple sensors. I wouldn't trust the cheap ones to last.

[themagellan]

This idea is awesome!

Should definitely print a 3D case asap!

I would ask why you don't step up to something a little more powerful like a piZero and a real lcd? If you're familiar with Python you could really write some cool functions (and people would even have a small computer if you preloaded it with rasbian and a mini wifi chip )

[loxxrider]

Why not Pi based? Simply becuase it's not necessary for what I've set out to achieve here. All I want is to read 5 thermocouples, display them, send out some analog signals for other things to read, and set some alarms off. Plus, analog inputs aren't native to Pi and I like the simplicity of not having an operating system etc,... It s just more things to go wrong. Keep it simple and it'll be robust! It's a think harder, not smarter kind of thing. Like bringing a gun to a knife fight... It might get the job done, but it's a little overkill, and a knife will never jam or run out of ammunition

[loxxrider]

Also, I haven't had much time to work on this for the past few days, but I'm learning what I can in my spare time so it can have menus with features that get stored in memory, etc.

I am going to be attending some training in Houston though for about a month starting next week, and I suspect I will have some time there. I just received a pelican case for all my gear too, so I will probably bring it with me.

[loxxrider]

Oh, and I'm just trying to finalize all the hardware before I have cases made. Honestly, the cases seem like they're going to make up a lot of the expense, so I'll be doing as much research there as possible to come up with a practical solution.

I am dedicated to this though. At the very least, I'll have 10, 5 channel thermocouple amps available in 2-3 weeks. The rest of the stuff will take a little while longer to sort out.

Also, I did do some thinking about incorporating vems display functionality. I could make it selectable with a button, but it'll require a lot of extra time and some more hardware that I didn't anticipate. I'll be able to develop a solution to that separate from the standard offering though, so it shouldn't slow things down there. Custom cabling will be required, but I can make a solution for that available.

[PRY4SNO]

What about 3d printing the case, would that keep down costs?

Sent from my SM-G900W8 using Tapatalk

[loxxrider]

Not necessarily. There are lots of standard cases available which just require custom front plates. The price for them is reasonable, it's just the custom front plates which are pricey. I can think of many ways to keep it cheap though. You just sacrifice in areas like esthetics. I'll come up with some options and present them here when I can.

[alxdgr8]

Is the LCD you're looking at dimmable by chance?

[themagellan]

Is the LCD you're looking at dimmable by chance?

if theres a processor to control the volts then sure why not?


Chris understood on your reasoning and it makes sense that this is a very specific project. Was just saying you should also think about what more this could do.

Also... you looking for good paying work? If you are send me a PM

[loxxrider]

Yes it will be dimmable. I haven't decided if it'll be done in software or via the vehicles dimmer. I'd prefer the cars dimmer.

Absolutely mage. That'll be for whatever the next project is I'm always interested in more money. Tell me lol.

[loxxrider]

It has taken me a little while to get this thing figured out becuase the documentation is awful, but now I believe I've come up with the smallest possible solution for the display while still retaining all the features I want.

More than 6 channels will require the 4 line screen or will require switching the display between two sets of sensors periodically.

This screen will require some kind of small board behind it just for an interface to a connector, and for mounting, but the package will still be waaaaay smaller than a normal 4 line LCD.

Now I need to denounce the buttons used for menus and settings and add the ability to save settings into memory.

20160423_152414.jpg (2.35 MiB) Viewed 5158 times

[loxxrider]

Oops, I just realized the temperatures are getting cut off in the picture haha. Too much spacing.

[my2000apb]

yay i want a 6 cyl versioN!

[loxxrider]

The first 5 channel amp was completed and sent to me this week. I will be able to take delivery of it in a few weeks (I'm currently in Houston). I hope to make some more progress on the code tomorrow. The program runs on the smaller LCD now (that's what I did last Sunday), and now I just need to refine it for use with menus and settings. I hope to knock most of that out this weekend.

[loxxrider]

I'm posting in celebration of FINALLY figuring out how to debounce the buttons and create settings menus on the LCD. With normal push buttons, the button will register the initial press, but then will register several more presses due to the springiness of the internal mechanism. So you can actually have the button press register many times in the code when you only pressed it once. That sucks! It makes for a program that seems really buggy. But I've fixed it now

Now I have to figure out what settings I want to allow and how to store them into memory. Also, how to adjust each setting. I'm fairly certain I'm just going to use two buttons to control everything.

[PRY4SNO]

Nice! I like simple for something like this. Makes it easier to use on the fly.

[loxxrider]

I am definitely going to keep it simple unless someone really feels the need for more functionality somewhere.

How precisely do you guys want to be able to set the temperature alarm? I was thinking increments of 25 or 50 degrees would probably be OK. If we need more than that, there are multiple ways I can change the way it is entered, etc. to get us there.

[loxxrider]

Also, what settings would you like?

So far I have:

Maximum brightness - This is just a limit on the max brightness the display's backlight will output. You will wire the display up to the car's dimmer (if you want), and you can dim it with the rest of the lights in the car. But if it is too bright, you have to either use a resistor inline with the display's power source, or you can just use this setting to tone it down a little. Currently, there are 10 brightness levels from almost off to full bright. I can make it more or less... or even infinitely adjustable if you want, but the latter case will come later in a firmware update if it's really wanted.

LCD Contrast - Adjust the contrast of the LCD screen from 1-20. This is what allows you to see the screen easily at any viewing angle. This is done in the software. There is no hardware required.

LCD Color - This will not apply for single color backlights, but if you want an RGB or Green/Orange backlight to match your interior lighting colors, I will allow you to adjust R, G, and B individually in this menu. I think increments of 10 (0-255) for each color will suffice for now.

Alarm Temperature - Determines at what temperature to set the alarm outputs off. Currently it can be adjusted in increments of 25 from 1000-1800 degrees F (1832 F is the upper range of the thermocouple amp currently when wired up to 5 volts).


I was going to put the peak-and-hold clear function in here too, but I think I will do something different. Currently, the settings/menu access is from "Button A". If, during normal operation, the user presses "Button B," the LCD will display the highest temperature since the power to the hardware was cycled. If that same button is then pressed and held down, it will reset the peak and hold. Sound good?

What else do you want to be able to play with? There really isn't much else you could do except switch between F and C. I will consider that in the future. The nice thing is that any extra functionality will be user-up-loadable to the hardware as long as you have the appropriate USB cable and software (the software will be/is free).

[loxxrider]

Very good progress made today. Software-wise, all I have to do is:

-figure out how to put and get settings into and out of memory
-program the peak and hold function

Everything else is in and fully functional! No bugs!




I also tested out the alarm functionality. I bought a bunch of piezo buzzers at Radio Shack and MAN did I find a loud siren one haha. I figure we need as loud as we can get with our open downpipes and stuff since we are such hooligans around here. You can use any buzzer you want though.

The next big challenge will be figuring out how best to package it all. I've found that I can get a really nicely-priced micro controller for this which is a lot smaller than a standard Arduino and has all the features needed (and nothing more) for this setup. It will allow me to bring the overall cost down by $15-20 and package things a little more compactly. The limiting factor here will be the size of the thermocouple board I believe.

[loxxrider]

More questions:

How would you like the LCD to be delivered? In some kind of small enclosure (added cost and design time) or just on a circuit board with mounting holes? Would you like the settings/menu push-buttons attached to the circuit board or separate for remote mounting? Separate is probably easier and more flexible, but then you have to mount them separately.

If the buttons were separate, would you want the wires for the buttons to go to the LCD's board or to the main hardware module? Either is possible.