Preview: Upgraded Bread Machine Incubator TR444 [in progress…]

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Ok. So! Back to hardware / electronics projects!! Yay!

This is a preview for an upcoming post. I am currently working on upgrading my Hacked Breadman Breadmachine TR444 Incubator from a previous project. I’m adding some RGBW neopixel LEDS from Adafruit for light. It will have a button to change lighting sequences from White to red/blue to purple, to blue, to black. All the colors one would need to 1. see into the machine. 2. Color LEDs to grow seedlings for gardening. 3. blue which may come in handy for bacteria cultures? IDK. maybe not. But whatever. I currently have the arduino code for the light sequence working.

I will also be adding a fan for circulation. I 3D printed the fan holder. I may or may not have a button to control the fan. I will have a big red button to start the incubator cycle (37 Degrees C for bacteria / fungal petri dishes). And i am considering another button for a programmed Dry Heat Sterilization routine. As mentioned before, according to Wikipedia:

The proper time and temperature for dry heat sterilization is 160 °C (320 °F) for 2 hours or 170 °C (340 °F) for 1 hour.

I also think i will be integrating my Chronodot real-time clock for use with this dry heat sterilization routine and possibly some other incubating cycle as well. Cool! Fun stuff! Lets get working!!

p.s. post in the comments if these are the kind of projects you’d like to see more of of! 🙂

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Bitten by the Electronics Bug

So recently I’ve been bitten by the project bug again. And quite a bit by electronics hobby-type stuff again in particular, though not exclusively. More blog posts and updates to come soon.

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On the left is my old homemade DIY arduino based avr high voltage programmer made on old Hewlett Packard Engineering Protoboard based off of Jeff’s original design that i made in 2011. On the right is my brand new updated model named the AVR HV Rescue Shield 2 from MightyOhm.com. It’s main function is to help reset the fuses on AVR chips when you program them wrong. My old one came in handy and has saved a few chips from time to time. The new one obviously is better, mostly because now that i’m tinkering more with attiny85V chips i now have a High Voltage Rescue shield for them too, though it also does not require an external 12VDC power source as it has some sort of built in surface mount step up voltage chip.

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So as briefly mentioned above i’ve been tinkering with trying to program attiny85v AVR chips. I’ve dug out my old trusty USBtinyISP AVR Programmer and I’ve recently gotten a Sparkfun Tiny AVR Programmer.

What i’m really intending to do is make a shrunk down version of my old Mystery Project by re-purposing and reprogramming my Adafruit TV-b-gone kit. I just need to get the frequency right. I’m starting by seeing if i can compile and upload the tvbgone AVR/arduino code to a blank attiny85 first. If i can do that i can work on changing the code. So far though i haven’t gotten the AVR fuses correct yet to use the tvbgone’s external 8mhz oscillator, though i think the program has uploaded correctly. That’s why i needed the HV Rescue Shield 2 mentioned above.

In addition, i finally ordered the parts to finish my DIY Arduino MENTA boards. They are cool Adafruit designed Arduino compatible boards that fit into an Altoids mint tin.

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Some of the other items I’ve been tinkering with have been Raspberry Pi’s, including various Linux-based Operating Systems including Raspian (a debian based distro), Octopi (debian running Octoprint – 3D printer software), and RetroPie (an emulator to play old roms for NES, SNES, Playstation, Atari, Gameboy, and other popular gaming systems). The tiny $5 Raspberry Pi Zero. Tinkering with automatic plant lights and a gardening moisture sensor. And my fancy new SparkFun Vernier Interface Shield an upgrade to interface my Vernier sensors with Arduino. More on that in another post soon!

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I also recently ordered a USB cable in order to salvage a scrounged barcode scanner that my brother saved from the Barnes And Noble dumpster. The USB cable works! Now i just need to figure out a use for it. Not bad for a $10 cable on ebay to a functional $200 value barcode scanner.

DIY Modified Bread Machine Incubator

I hereby present: “The Breadman Incubator”… TaDa!

I will admit that i never truly got into the DIYbio movement, but to say it didn’t leave an impact on me also wouldn’t be truthful. So what is this machine? And what is it for? Well, I’m glad you asked…

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In short this is a modified bread machine. Only modified to the extent that the native electronics have been replaced with an arduino (in this case an old low-cost diavolino), an arduino screw-shield, the native thermistor replaced with my own 10k ntc thermistor, and a 7 segment display from sparkfun electronics. Oh, and my own custom orange plexiglass cover! I’m quite proud of that cover! It’s main design is to regulate specific temperatures. In the case of DIYbio, in theory it can be used to regulate a temperature to be an incubator. Mainly bacteria, but it could also be used as an egg incubator, or a “hyper germination chamber” for squash seeds!. This last one is the only one i have actually tested, and i was able to see a squash seedling emerge in only one day! All of these potential uses still fall within the category of do-it-yourself biology.

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Currently the programming is limited to a pre-set temperature at 37 degrees Celsius. This is often the optimal temperature to cultivate bacteria. Or so i’m told by Wikipedia. It is also the max temperature listed as being able to germinate squash seeds. huh, who knew?

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Now, a lot of people out there might say: “why on earth would you want to cultivate bacteria!” and one step further: “why on earth would you make a machine to grow bacteria!; Isn’t that dangerous?!” Well, umm.. I never said i actually would grow bacteria in this thing, more i created it just because i like the “i could” factor. In reality this is more of a proof-of-concept design built only to impress myself. But to answer the second question/statement.. Yes, growing bacteria is potentially dangerous.. unless you know what you are doing, what kind of bacteria is safe to work with, and proper safety protocols. Those who are familiar with the DIYbio movement will know that such safety concerns have been discussed before and that the general consensus is basically “use common sense” and “know what you are doing”. If these two principles are followed everything will be fine.

Besides, the great thing about this is that in theory this could be programmed to be it’s own sterilizer too! That’s a great plus for safety. Wikipedia say’s this:

Eventually, the entire item reaches the proper temperature needed to achieve sterilization. The proper time and temperature for Dry-Heat sterilization is 160 °C (320 °F) for 2 hours. Instruments should be dry before sterilization since water will interfere with the process. Dry-heat destroys microorganisms by causing coagulation of proteins.

I did a basic programming test to see if this machine could reach 160 degrees Celsius. It seemed like it could. The only thing needed would be a way to accurately keep track of time (like the unused chronodot i have lying around) and a button or something to initiate a programmed sterilization routine.

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In this design i have not implemented use of the motor. One because i really couldn’t think of a good use for it. But two because in my initial testing phase i accidentally destroyed both an arduino mega and my computer (i assume by not properly protecting them from the kickback electricity from the motor). Yeah, it was “my bad”! Quite literally. Yeah, so a caution to anyone who decided to build a similar project, i recommend not programming your arduino while it is plugged into the electronics of your bread machine. Program it first, and then hook it up to test it. It was only when the usb cable of my arduino were plugged into my computer (with the motor running (i think)) that bad things happened. 😦

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I found this old piece of scrap aluminum that handily fits at the bottom to cover the motor thingy. It gives it a nice flat surface. Petri dishes or anything that needs a flat surface will need something like this.

So.. Does it work?.. Yup. At least in a basic sense. It definitely could use some improvement. The programming is very basic in terms of turning the relay on if it is under a preset temperature (in this case 37°C) and turning it off it is above. While this works, it is not efficient nor really all that accurate. A PID loop would probably improve it much. Also adding a chronodot would help to have a temperature compensated accurate time clock in case i wanted to incubate something for a specific amount of time. I probably will add the chronodot at some point. A fan to help regulate temperature might also be a good fix, but if the autoclave feature were implemented it would have to be autoclavable (or removable). The fan could unintentionally introduce mold spores, but if proper sterilizing techniques were used this could be avoided. And perhaps a magnet switch to turn things off when the cover is opened.

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The arduino code for this project can be found here.