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2019 Jiggering-Casting Project of Medalta 66 Mug
A cereal bowl jigger mold made using 3D printing
Beer Bottle Master Mold via 3D Printing
Better Porosity Clay for Brown Sugar Savers
Build a kiln monitoring device
Coffee Mug Slip Casting Mold via 3D Printing
Comparing the Melt Fluidity of 16 Frits
Cookie Cutting clay with 3D printed cutters
Evaluating a clay's suitability for use in pottery
Make a mold for 4-gallon stackable calciners
Make Your Own Pyrometric Cones
Making a high quality ceramic tile
Making a Plaster Table
Making Bricks
Making our own kilns posts using a hand extruder
Making your own sieve shaker for slurries
Medalta Ball Pitcher Slip Casting Mold via 3D Printing
Medalta Jug Master Mold Development
Mother Nature's Porcelain - Plainsman 3B
Nursery plant pot mold via 3D printing
Pie-Crust Mug-Making Method
Plainsman 3D, Mother Nature's Porcelain/Stoneware
Project to Document a Shimpo Jiggering Attachment
Roll, Cut, Pull, Attach Handle-making Method
Slurry Mixing and Dewatering Your Own Clay Body
Testing a New Load of EP Kaolin
Using milk as a glaze

Build a kiln monitoring device

The actual firing schedule experienced by ware in a kiln can be very different from the one programmed into the controller (e.g. heavily packed kilns may heat or cool slower than programmed). Many glazes depend on specific schedules, it is important to have a record of what happened in the kiln to diagnose any problems.

In the process of this project to build a monitoring device we have hit a number of dead ends. But each, plus the rapid development of controllers, has made the potential of this device more evident that ever. Our aim to be able to log firing curves into an insight-live.com account (so they can be linked to test result records or viewed beside the actual controller program). Thus, this is not a kiln controller, it is a data logger (we are not disturbing the controller already on the kiln).

The advent of ESP32 microcontrollers is a game changer. These are RISC-V processors with unbelievable power, they sell for $10 or even less. They have a wifi antenna, enabling interaction using any device with a browser, but they do not have a conventional operating system that can be hacked from an external source. The device we want to make will only send data to an online API at Insight-live.com, all interaction will be done there, totally out-of-band. It will not have any "push" technology, no outside source will be able to give it any kind of command. It will have the ability, on its own, to access the API to get information. The complexity of this device will thus be kept to an absolute minimum, just enough to recognize the commencement of a firing and sending measurement data at defined intervals. That will enable us to put all the ease-of-use development effort into the web page that reports the measurements of the monitor.

Related Information

Inside a kiln with a Bartlett Genesis controller


A Bartlett Genesis kiln controller circuit board

The 220V enters lower left to a terminal block. That splits to a transformer (above) and relays (below that). The 4-07-6024 transformer supplies power to the SMT_3140 controller board (converting the 220V down to that needed by the circuit board). The controller is run by an MSP430 Texas Instruments microcontroller (lower left closeup). That controller has inputs from the thermocouple and a current monitor (yellow donut shape around the wires going to the elements). The board has outputs that connect to the relay, that relay in turn controls the flow of current to the elements. This is a simple device, but not something to be replaced lightly. DIY controller boards documented online look tempting but they are not CSA or UL approved (so fire insurance coverage is implicated). Commercial controllers focus on safety and liability over functionality, they handle intermittent thermocouple connections, bad thermocouple readings, stuck relays and shorted and weak elements - these are runaway conditions that could become meltdowns in a kiln controlled by a DIY device. This being said, these commercial products do have a weakness: The relays. They are mechanical devices and are the first thing to need replacement. Kiln controllers thus need To be good at recognizing relay failure.

Kiln Firing monitor - Going in the wrong direction


So many glazes appear as they do because of the firing schedule (especially the cooling curve). Imagine getting an awesome result out of a kiln and not knowing (or being able to replicate) the exact firing schedule that produced it. Or a bad result and being able to relate that to the firing schedule that actually occurred. This is not a kiln controller, it simply reads and records the temperature once per minute. It is a Raspberry Pi computer with camera that reads the temperature display on the kiln (using machine vision). This seemed like a good idea at the time, but adding all the difficulties of reading the display turned out not to be worth the trouble when it is so easy to connect a dedicated thermocouple. Further, the device is too capable. Being an entire Linux computer it would be a vector for hacker intrusion into the host wifi network unless being constantly updated (a large Las Vegas casino was hacked recently, the vector into their network was an iOT aquarium thermometer). While it can be programmed as an access point, hosting its own wifi network, this is too much trouble to use, people are not going to want to constantly change their wifi connection. More problems: Its complexity means there are too many things to go wrong, it uses too much power for battery operation and is a hassle to plug in. Most importantly, the computer knowledge required is well beyond the ability of the average person to navigate.

Type of components needed to develop a kiln monitoring device


These are all very inexpensive and easily available.

When the prototype is working we will incorporate the software into a ready-made, battery-powered device that uses this same controller chip. It is likely that the display will not be needed for logging operations, the device will simply watch for temperature rise and automatically begin recording when that happens.

ESP32 devices with cases, screens and batteries


There are many options like these for the packaging in the final logging device. The one with the larger screen here costs ~$50. The device with the small one has the same computation and communication abilities (but is much less expensive).

The screen will likely be used for simple status information to assure the device is running and recording. Both devices have a button, it may be possible to use this to initiate recording of a firing (other devices have multiple buttons). Both of these are available without a display, it may not be needed once we are assured of reliable operation (its absence would greatly extend battery life). That being said, a display might be handy to show firing or switch-setting schedules as a reference for programming the controller on the kiln.

Links

Glossary Firing Schedule
Designing a good kiln firing schedule for your ware is a very important, and often overlooked factor for obtained successful firings.
Glossary Drop-and-Soak Firing
A kiln firing schedule where temperature is eased to the top, then dropped quickly and held at a temperature 100-200F lower.
Glossary Kiln Controller
In ceramic kilns the firing schedule is typically managed automatically by an electronic controller. But that may not mean that ware gets automatically fired to the correct temperature and atmosphere.
Typecodes Kiln Controller Device List
If you are aware of devices not listed here please contact us. We want to focus on those in active development. Devices supplied on manufactured kilns are usually relabelled, they are not actually made by the kiln manufacturer.
By Tony Hansen
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