Visible on front: 3RT1024-1A..0
Visible on side: EAN 4 011209 291027
Probably this one:
Siemens 3RT1024-1AP00
http://www.conrad.com/ce/en/product/502380/Siemens-SIRIUS-3R-contactor-3RT1-Siemens-3RT1024-1AP00-S0-230-Vac
https://www.elfa.se/elfa3~se_sv/elfa/init.do?item=36-228-29&toc=0&q=3rt1024-1a
https://www1.elfa.se/data1/wwwroot/assets/datasheets/3RT_1015-1034_eng_tds.pdf
http://cache.automation.siemens.com/dnl/Tg/Tg0NzM0MQAA_6009084_HB/03_1sirius_en.pdf

Size S0
Rated control supply voltage Us at 50Hz: 230

How much current is needed for A1/A2? 61/230 = 0.265A = 265mA
Looks like 61VA max and 7.8VA when closed according to:
http://docs-europe.electrocomponents.com/webdocs/058e/0900766b8058e7af.pdf

Visible on back of TR 210: Sensor Type S and Alm
https://en.wikipedia.org/wiki/Thermocouple#Type_S
http://srdata.nist.gov/its90/type_s/0to300.html
http://srdata.nist.gov/its90/download/type_s.tab
[http://www.omega.com/temperature/z/pdf/z021-032.pdf Thermocouple theory]
[http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/temperature-measurement/thermocouple/thermocouple-noise-filter Thermocouple Noise Filter]

Thermocouple-to-Digital, type S SOIC8 MAXIM 31855
MAX31855SASA+
http://se.rs-online.com/web/p/temperature-humidity-sensors/7833894P/
http://docs-europe.electrocomponents.com/webdocs/1252/0900766b81252ffc.pdf
[http://archives.sensorsmag.com/articles/1297/sw1297/main.shtml Software Linearization of a Thermocouple]
http://www.maximintegrated.com/en/products/analog/sensors-and-sensor-interface/MAX31855.html
http://www.maximintegrated.com/en/products/analog/sensors-and-sensor-interface/MAX31855PMB1.html

http://www.susa.net/wordpress/2012/06/raspberry-pi-relay-using-gpio/
G5LA-1 DC5
http://se.rs-online.com/web/p/non-latching-relays/0492884/
http://docs-europe.electrocomponents.com/webdocs/0b76/0900766b80b76b3c.pdf
Trans GP BJT NPN 45V 0.8A 3-Pin TO-92
http://se.rs-online.com/web/p/bipolar-transistors/6711116/
http://docs-europe.electrocomponents.com/webdocs/0d22/0900766b80d22eb3.pdf
1N4004-E3/54, Rectifier Diode, 1A max, 400V, 2-Pin, DO-204AL
http://se.rs-online.com/web/p/rectifier-schottky-diodes/6289029/

Since the rise rate of the current (di/dt) of most systems is very fast (usually fractions of microseconds) “fast”, “ultrafast”, or Schottky diodes are used. Regular power diodes, such as the commonly used “1N4007” series, are not suitable as snubbers as their reverse recovery time (turn on time) is several tens of microseconds; the diodes do not turn on fast enough to suppress the fast voltage spike.

AMP 182694-1
Cable outer diameter 7.5mm
Cable 10 wires 2 separate shielded for thermocouple sensor
Contact inner diameter of dragavlastning 19mm
Contact (contact side) outer diameter 21.5mm
Lead size, outer diameter 1.5mm core diameter 0.5-0.6mm = 0.20-0.28mm2

Spänningsdetektorkrets SOT-23-5, STM6321LWY6F
https://www.elfa.se/elfa3~se_sv/elfa/init.do?item=73-457-48&toc=0&q=watchdog+timer
https://www1.elfa.se/data1/wwwroot/assets/datasheets/stm6321-22_6821-5_eng_tds.pdf
MAX823, MAX824

Watchdog-krets DIL-8, MAX813LCPA+
https://www.elfa.se/elfa3~se_sv/elfa/init.do?item=73-256-24&toc=19912

WD that stays low until WDI is active MAX691CPE+
https://www.elfa.se/elfa3~se_sv/elfa/init.do?item=73-691-01&toc=0

Interesting but not quite what I want
http://raspberrypihobbyist.blogspot.se/2014/01/fail-safe-circuit-using-discrete-logic.html

http://www.megaleecher.net/Watchdog_for_Raspberry_Pi

Elfa 37-071-60 5VDC 200mW - G5NB-1A-E-5VDC
Elfa 71-014-58 Transistor TO-92 NPN 45V - BC337-25
Elfa 10-526-25 Likriktardiod DO-41 400V 1A - 1N4004

http://www.petervis.com/Raspberry_PI/Driving_Relays_with_CMOS_and_TTL_Outputs/Driving_Relays_with_CMOS_and_TTL_Outputs.html

Relay: 5 / 125 = 40mA needed
BC337-25 100mA - hFE 250
40mA / 250 = 0.16mA needed for Ib base current
3.3 / 0.16mA = 20625 Ohm

Relay: 5V / 27.8ohm = 180mA needed
2N4401 150mA - hFE 100
180mA / 100 = 1.8mA needed for Ib base current
3.6 / 1.8mA = 2k Ohm (2.kOhm turns out to give ~140mA through the spool)
http://se.rs-online.com/web/p/non-latching-relays/6839065/

http://www.interfacebus.com/voltage_threshold.html

Transistor TO-92 NPN 40 V 600 mA, 2N4401
https://www.elfa.se/elfa3~se_sv/elfa/init.do?item=71-300-09&toc=19104

6VAC - 6VA - 2x6V, 0.5A Transformer
GBU405 rectifier
4700uF 16V
100uF 16V
.1uF ceramic
L4940V5 LDO voltage regulator
Here are some tests - LinearPSUTests

Vout = 1.21(1+R2/R1) + Iadj * R2
Iadj = 3uA

R1=3.9k

Vout = 1.21 + 1.21 * R2/R1 + 3e-6 * R2
Vout - 1.21 = 1.21 * R2/R1 + 3e-6 * R2
R1(Vout - 1.21)/1.21 = R2 + 3e-6 * R2
R1(Vout - 1.21)/1.21 = (1 + 3E-6) * R2
(R1(Vout - 1.21)/1.21)/(1 + 3E-6) = R2
R1(Vout - 1.21)/(1.21 + 3.63E-6) = R2

Vout = 4.5 - 1.21, R1 = 3.9k
3.29 * R1/(1.21 + 3.63E-6) = R2 = 10.6k

Vout = 5.5 - 1.21, R1 = 3.9k
4.29 * R1/(1.21 + 3.63E-6) = R2 = 13.8k

Assume trimpot goes between 2.6k - 26k (not from zero)

13.8k-10.6k = 3.2k
8.2k - 5% = 7.8k
13.8k - 7.8k = 6k

1/6k-1/26k = 1/X
X = 7.8k

Use 8.2k E12 value (will get 6.2k trimpot)

So R1 = 3.9k, R2 = 8.2k + 26k || 8.2k

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