Experimental Incubator/ei prototype designing

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2.1 "Mamut" - Current prototype of experimental incubator

One of the most important things which we have to decide on is "how do we want to do it?" meaning mostly in this case the practical way of building up a prototype. Below are strategies which we were implementing so far.

Pin out diagram

  • Industrial prototyping

Inspired by my (Algoldor's) friend Arnd we choose to go by "industrial prototyping". Simplified: get well supported and functional parts for bit of extra cash and build up the first functional prototype from them. Afterwards when the prototype is working, start to break it down part by part redesigning them or using another cheaper/more feasible variants shaping the incubator to your like, bringing the costs down. This approach seems to be bit more expensive to start with but it ensures that even less experienced contributors to the project would be able to build their functional experimental machine, having than what to work with which I think is crucial. For more info please check this page created at Techinc hackerspace by Arnd. Till we get a proper PCB design and assembled kit you need to have some certain electronic skills set to get "smoothly involved" in the project. The more easy to put together kit option should be ready for 31c3 in December 2014.

Short time goal - 3-4 prototypes 2.1 mamut build - deadline end of April 2014

By the end of April we want to have three to four prototypes of 2.1 mamut running in different locations so we can test in reality the design which we choose to apply both hardware and software. The aim is to measure, display and control temperature, both heating and cooling using the kit which we presented at 30c3, sharing updates through our forum and incubator mailing list, software updates especially at Github. Next step after few months of testing, reporting on the progress and summarizing of the results will be design of the PCB boards which are base for 2.2 mamut kit version. This should be due at the end of July or during August.

Medium term goals - PCB and kit design 2.2 mamut - summer to winter 2014

After few months of testing of the first prototype 2.1 mamut we will design printed circuit board (PCB board) which will be base of our experimental incubator kit - 2.2 mamut prototype/model. This one will be assembled and tested for two or three months, aiming to have all the bugs out by end of September 2014 if possible, mid of October latest. Suggestions for this prototype are:

  • optimize the use of current Arduino outputs
  • create and apply design of PCB, possibly one for the "brain" and separate for the "relay or H-bridge" module, preferably all on one board
  • the type of relays used (mechanical or opto-relays) and/or H-bridge has to be decided

By the end of November the final run of tests needs to be done resulting in final version of the experimental incubator 2.3 mamut kit version confirming the final design and promoting and funding it most likely by crowdsourcing campaign ordering larger quantities of components (latest end of November) which will be presented and circulated at 31c3 congress as Experimental Incubator 2.3 Mamut.

  • Parts needed to build up prototype/kit for 30c3

(parts suggested based on industrial prototyping scheme)

Component Function Model Specifications Amount Cost (€) Purchase links Component Suggested by
Arduino Board (clone OK) easy prototyping ??? 1x 15 DealExtreme Arnd
Arduino prototyping shield for easy prototyping ??? 1x 2 DealExtreme Arnd
LCD Display display data ??? 1x 7 DealExtreme Arnd
Temperature sensors to measure temp. ??? 2x 8 DealExtreme Arnd
Solid state relay switch on/off 220V elements ??? 2x 6-10 DealExtreme Arnd
H-bridge changing polarity of peltier ??? 1x 13-16 Ebay Arnd
RTC (real-time-clock) module keep count of time DS1302 based 1x 3 DealExtreme Arnd
Connectors for temp-probes connect the temp-probes ??? 2x 1 DealExtreme Arnd&Erwin
Pin Headers for Arduino (package of 5pcs) to connect boards ??? 1x 5 DealExtreme Arnd
Thermopaste to connect heatsinks to peltier ??? 1x 5 DealExtreme Algoldor
peltier element for heating/cooling ??? 2x 8 GM electronics Lars/Algoldor
cooler for heat distributiong ??? 2x ??? Arctic Lars, Algoldor

An overview of pins used for 2.1 Mamut

An overview of Arduino/Atmega328 pinouts

The following table then emerges:

D0: Serial RX

D1: Serial TX

D2: SSR1

D3: SSR2

D4: LCD D4

D5: LCD D5

D6: LCD D6

D7: LCD D7


D9: LCD 'Enable' (might be optional)

D10: LCD backlight control (might be made optional)

D11: One-wire bus 1 (first temp-probe)

D12: One-wire bus 2 (second temp-probe)

D13: Free (see note below about LCD and buttons)

A0: LCD Buttons

A1: Free

A2: Free

A3: Free

A4: I2C SDA-line for DS1307

A5: I2C SCL-line for DS1307

This leaves one digital pin free in a 'plain and simple way' of connecting two SSR's and two temperature-probes. We could free up two digital pins with the LCD, even more if we move it to an I2C-based way connecting it (saves another 2 to 3 wires, I believe), at the expense of more code/parts. As it is, it's not required for what we want to achieve with the device right now.