TAP / Genisys touch-screen controllers

[adrian]

HI Folks
I was looking at buying a spare 3-key controller for my home-built fibre kiln (single thermouple - single 7.5kw element).
Skutt seemed to want silly money for the one that comes with their Hotstart kilns (which is the controller I'm using at the moment)
- so I started looking at the new touch-screen controllers - Genisys from Bartlett and TAP from SDS.

Pricewise they're much of a muchness (about USD 350) ... and I see that TAP has just added WI-Fi to their offering for remote monitoring - which is something I'd been looking for.

So - does anybody have any real-world experiences/recommendations/advice on either controller?
Thanks
Adrian

[Kevin Midgley]

Might want to search Ebay.ca for Canadian sellers there was one there selling controllers quite cheaply and of course you are making payment in Canadian dollars.
PerfectFire, if you can find one of them, were cheap to start with and somehow one seller was selling them for even less.
Less than half what you have been thinking.

Of course for the best there is always Digitry.com

[Kevin Midgley]

There is also the possible use of Raspberry Pi as a controller.
This link will take you to other links and its wireless setup etc.
It is all cheap but you have got to be able to play and have time.
No time? Digitry.com for plug and play

http://www.digikey.ca/en/articles/techz ... cifQ%3D%3D

[adrian]

HI Kevin
Thanks for the replies.
As it happens, I have two Raspberry Pi 3's sitting on my desk at the moment...
Plan A was to hook one of them up to the spare thermocouple in my kiln, and use it as a remote monitor (via wifi) of what the kiln was up to.
Ideally, this would include a graphical output.
Currently, one of the pi's is reading the temperature of a thermocouple that's also sitting on the desk <g> - but it's a start..
and, at 30 euro or so for the PI and 3 euro for the thermocouple interface board, it's certainly cost-effective.

Having implemented the 'measuring' bit, the next step would/could be to code up the temperature/kiln control bit - and that would be 'it'.
I'm currently learning Python - all my 'paid for' work was in assembler, but I was a bit younger then <g>

I'm mindful of the safety aspects (have worked with microprocessor control in industry for some years) - but I'm thinking that none of it is particularly complex...
and would work out considerably cheaper (not counting my 'time'!) than the ready-made solution.

A major part of the plan is to enable remote monitoring of the kiln. It's only a dozen steps from the house to the workshop, but it'd be nice to be able to use a pc or a tablet to just have a quick peek at what's goimng on with (say) an overnight firing - and the commercial controllers treat this remote access as an expensive add-on.

By the way - the digikey link is all about solar power for a Raspberry pi - wonder if you intended to link to a page about kiln control with the Pi - or if it was a general 'Rpi' link?
I might give it a go!

Thanks
Adrian

[Kevin Midgley]

yes but on the 'ad' side, the right side of the link were other links to working with Raspberry Pi's. That is what I thought you'd find interesting.

[JestersBaubles]

There are apps that let you turn a spare phone into a wireless, IP connected camera (I know there is one for Android, don't know about iOS. Most of us have an old phone lying around...). Also, wireless cameras are very cheap these days... you might want to look at woot! (woot.com)

Dana W.

[adrian]

HI Kevin.
Ah - sorry - missed that!
Actually, I did come across the following site

https://apollo.open-resource.org/missio ... picoreflow

which contains hardware details and freeely-downloadable software to run a Raspberry Pi as a temperature controller, lan-accessible, with a graphical display of firing schedule and actual temperatures.

I downloaded & installed the software onto one of my Pi's last night - and it's looking very interesting..
Haven't actually hooked it up to my kiln yet - but it seems to do most of what I was wanting..

Probably the biggest 'snag' is that it was designed originally to run a solder reflow oven - so it's programmed in terms of time & target temperature, rather than the "ramp / temp / hold" that we're used to - but that's just a bit of maths, really.

It allows storage/modification of multiple firing schedules, so one for fast full-fuse, one for slump etc - plus you can log into the Pi over a local network and monitor progress on a firing schedule - which is just what I wanted..

It's great that people are happy to give their time & expertise to create such open-source software - quite restores your faith in human nature <g>.

Once the current 'rush' of fusing work is passed, I'll be looking to wire this system up to my existing kiln relay box, and we'll have a play!

Thanks
Adrian

[adrian]

HI Dana
Yes - that's another way of doing it..
There's a pc in the workshop (mostly used as an MP3 player!) - so that could easily have a webcam connected to it - but I was looking to have the ability to actually 'control' the kiln remotely..
As you'll see from my reply to Kevin, I may have found a (cost-effective!) solution
Thanks
Adrian

[FlorianFranken]

Hi Adrian,

I have built a controller for my kiln using an arduino, found it quite easy to code (processing based I believe),
there are shields available to add wifi functionality, although I have not looked into that.
Have used raspberry pi for other projects but I find them a bit unstable..

Check this out for the code that I based my controller on: http://ospid.com/blog/

[Kevin Midgley]

Adrian, I pay no attention to 'ramps' with my Digitry controllers. It is all time and temperature as those are the parameters you enter.
These new computer chips the Arduino and the Pi are probably more sophisticated than the Z80 chips that run the Digitry which goes to show the technology is not difficult.

One thing to consider when trying to save money firing kilns and controlling them as cheaply as possible is the cost of glass factor. You can rapidly pay for the comparably expensive Digitry controller with one glitch or failure to fire properly due to a programming error. Glass is not a cheap material and a wrecked firing can be hundreds of Euros worth of glass that could have been saved by going with the off the shelf Digitry.

In a past life I had used multiple Digitry units. When I was rebuilding my studio I had the option of trying to save money on the controller, possibly a few thousand dollars, and I went with the reliability of the Digitry which has never let me down in around 35+ years of firing glass. I know I have saved a fortune in the glass I have fired successfully.

Another factor was I'd lost all my on paper firing schedules and I didn't have to start learning to program firing schedules for a new controller from scratch.

[adrian]

HI FlorianFrankenstein.
Thanks for the comments - curious to know about you finding the Pi's unstable?
Can you tell me any more?

I guess - being a 'doing several things at the same time' kind of device - there's always the potential for problems.

Drawing on my past experience in automation (and a certain amount of paranoia! <g>)
- I was planning on running a separate 'max temperature alarm' circuit in hardware - which would be wired to kill power to the kiln in the event ov over-temperature,
and probably a hardware 'watchdog' circuit with similar capabilities in case the Pi 'wandered off' when it should have been doing something useful....

Thanks
Adrian

[adrian]

HI Kevin
All good points - 'the devil you know' and all that..
Understand about the potential value of a kiln-full of glass - though I must confess that my own kilnwork is rather more modest,
and, if I'm honest, there's a certain amount of interest in the 'can I do it myself?' aspect.

This particular homebuilt kiln cost me somewhere in the region of 1400 Euro three years ago - most of which was for the metalworking, as I don't 'do' welding
- and the equivalent commercial kiln is around three times that price to buy new. It's already paid for itself several times over.

There's a satisfaction for me in being able to do more for less - I guess I'm a product of a frugal post-war upbringing.<g>

It was many years before I discovered that you could actually _buy_ new shiny wire nails in a shop to fix things together with
- having sat for hours as a child watching Dad hammer old rusty reclaimed nails straight again!

Adrian

[FlorianFranken]

Like you, I built my kiln for a lot less than what a similarly sized one sells for (300 EUR vs 1800, even without adding about 400 for an off the shelf controller). I used pi's a lot for a home entertainment system in the past and they crashed every now and then, at least once a week, where I have never had an arduino project do that (when there wasn't a fault in the code at least). The pi is way more advanced/complicated, running basically a whole operating system, where the arduino runs your code and that's about it. Then again, there are some new generations of the pi which i have not used at all, so the stability issues could be solved. The pi has more graphical options, you could add a computer screen filled with data next to your kiln, but I feel an arduino with a basic LCD screen showing the temp/target temp can do the job more reliably. As you want to control via wifi, you can create all of the beautiful graphs that the pi could on your pc / tablet with the same raw data instead of having a pi do all that on top of controlling the kiln.

I am curious as to how a separate hardware max temp system would work? Don't have anything like that on my kiln, just a line of code that tells it to shut off in case of the thermocouple failing or temps exceeding 1100 C.

[adrian]

HI FlorianFrankenstein

Well done on the homebuilt kiln. One of the regulars on the board said to me 'it's a box that gets hot....' - and that just about sums it up.
Don't like paying over the odds for things that I can make myself <g>

Understand about the Pi - it's true that the more you ask something to do, the more likely it is to get it wrong.
I'm looking at the Pi3 (which is, I guess, even more complex!)
Has on-board wi-fi etc.

I've also played in the past with a thing called a PicAxe - which is more Arduino-like... still might go that direction, but the system I mentioned earlier came along, designed for the Raspberry Pi, so I'm taking a look at that.

As for the over-temperature, there's a chip which interfaces with a thermocouple (does all the cold-junction compensation thing) - and can provide a variety of outputs, including a straight (amplified) analogue of the thermocouple voltage, and it can also compare the thermocouple temperature with a voltage derived from a preset variable resistor, and pull in or drop out a relay when a preset maximum is exceeded. The plan is to use this chip to hold 'in' a safety relay (actually a 40A contactor) that's wired in series with the kiln power - so that, should the kiln relay stick shut, and the temperature go up beyond (say) 850c, the hardware safety circuit would operate and kill power to the kiln. This would also act as a safety circuit in case the Raspberry Pi had a funny 5 minutes and left the 'heat' relay locked on.
It needs a bit more 'relay logic' to make the safety relay 'latch' in the 'fail' position - but I had that all drawn out as well. Just got to build it now! <g>
The chip is here https://www.sparkfun.com/datasheets/IC/AD595.pdf - the attraction being that the safety circuit is all hardware and independent of the main micro-controller.

Adrian