Experimental Incubator/ei prototype designing
Here you can find info about the development of the experimental incubator (ei)current version 4.0 "Just" which we are now working on. There are several improvements compared to the previous version 3.0 Fermento, the third generation of the experimental incubator.
One of the most visible improvements are the professionally produced PCBs which we had ready at 33c3. Already for second time we have made complete kits, this time we had kits with all parts and also only bare PCBs for the more experienced ones.
How to get involved, contact
Get your kit. That is the most easy way how to get in and participating. Contact Algoldor, Justa or send an email to the experimental incubator mailing list. The total cost is around €35-40. The cost of the components in the kit is around €13, if you can afford to invest €25 (+ postage) that would be nice. Another €8 is for the solid state relay (SSR) and heat sink if you do not have your one already. Shipping should be around €5-10 depending where are do you live. Total around €40 or so.
If you want to get involved, you need help with experimental incubator set up and running or you have some other questions you can get in touch with us:
- at our experimental incubator mailing list
- directly with Algoldor by sending email to algoldor (you know the sign) foodhackingbase.org
- directly with Justa
- pop in our #foodhackingbase channel at oftc network, IRC
Soldering and connection
For the people who has the 4.0 just version kit (equals v2.1b) we have detailed instructions how to solder, connect and use this version under the soldering guide shared as a pdf file at TechInc wiki's.
Schematics
This design was made in KiCad.
SVG versions of the schematic and the PCB are provided at the right side.
For svg version of files click here (schm and brd).
You can find a tar.gz file of the combined files here.
For reference, the values for the resistors are:
- R1: 2K - 2k2
- R2: 330 - 360
- R3: 620 - 680
- R4: 1K - 1k
- R5: 3.3K - 3k3 (3k6)
- R6: 10K - 10k
- R7: 470
- R8: 470
Layout of the resistors:
R7
R8
R1 R4
R5
R2 R3 R6
Software
The software was written by Bigmac and Lars, the code is uploaded on Github here.
Programming
You will need a USB to serial (TTL) converter to program this. There are 3 brands of converter chips out there: prolific 210X, FTDI, CH340G each with their own driver issues... CH340G Drivers for windows and mac
Currently Run Prototypes
The prototypes which are currently running the "just" version are listed here:
- experimental_incubator_just_la_cherche, person coordinating Algoldor
Temperature probes
The DS18B20 temperature probes used have PVC shielding; that makes them unsuitable for long time use at temperatures of 100°C or above, although the sensor works up to 125°C. Some sensors are shielded with PTFE cable (more commonly known as Teflon) which is considered food safe to 160°C, so these sensors can be used up to 125°C (max sensor range). Here are some ordering options:
- [Cheapest found on DX - lead only 90cm, not 100!] eu 2.26
- [Cheap and tested sensor from DX] eu 2.53
- [Slightly nicer due to pins on leads] eu 3.37
- [Local source delivers very quickly] eu 3.25
- [Adafruit never cheap] $9.95
- [PTFE version on AliExpress] $8.50
- [PFTE version on ebay] eu 12.47
- [PTFE version on Adafruit - never cheap] $14.95
- [Local supply of PTFE version] eu 14.95
Bugs&Issues
- Displayed Time Error - Reported on 12/3/2017 by Algoldor. If the incubator is in the off function displaying only time, after several days the display stops showing "time" but starts to show variety of symbols without meaning. It seems like after the amount of the time displayed is too much for the display it crashes.