Mk138 based incubator

Kits Mini Kits Range
1

hello everbody

i am building an incubator based on the mk138

i need to regulate the temperature higher than the module allows

i am aiming for somewhere in the 35 to 40 range

(i actually need to maintain about 37.7)

what is the best way of doing this

changing the thermister or changing the resistors (as someone has posted)

it seems that the chap who changed the thernisters had a few problems with buzzing - rapid cycling of the relay i assume

if its a simple ntc thermister change what value would you recommend

many thanks in advance for any recommendations

cheers

mike

:smiley:

2

This kit is not suited for an incubator, the hysteresis is too high.
You can adjust the range by changing resistors as indicated on the PCB.
Please do not ask for values, experiment !
Remove the hysteresis resistor to obtain max. hysteresis.
As the unit will cycle continuously, replace relay with solid state relay
(e.g. http://www.velleman.be/ot/nl/product/view/?id=341825)

3

thanks for that ill have a play and see what i can do

mike

4

Did you ever find a solution for controlling your incubator at 37.7Deg. C? :slight_smile:

5

A bit late perhaps but I have several customers who built incubators for various purposes. They all use the K6002. Works even better than most commercially available products!

6

To increase the operating range of MK138 so it is suitable for use as an egg incubator thermostat (37.5º) with a hysteresis of approximately ±0.4º. Change the following components:-
Component Value Order Code
R4 4K7 1% 907-247
R5 3K9 5% 906-239
R6 2K7 5% 906-227
R7 10M 5% 906-610
RV1 1K 994-210