the idea came from this Applied Science Video: Electroluminescent paint and multi-channel control circuit 21 Nov 2018 starting at 11:25

there is a link to amazon for a element – and it is not available to delivery to germany 🙁 so i went on with some help of friends and found

to get an idea of how much power i actually need i had a look at the small commercial IR-Heaters and Hot-Plates – they all have about 800W:

180mm * 235mm = 42300 mm² = 423 cm²
a = 60mm * 60mm = 3600 mm² = 48 cm (1x4)
b = 60mm * 80mm = 4800 mm² = 48 cm (2x2)
c = 60mm * 90mm = 5400 mm² = 54 cm² (1x6)
d = 60mm * 120mm = 7200 mm² = 72 cm² (1x8)
e = 120mm * 60mm = 7200 mm² = 72 cm² (2x4)
f = 120mm * 90mm = 10800 mm² = 108 cm² (2x6)
g = 120mm * 120mm = 14400 mm² = 144 cm² (2x8)

423 cm² == 800W
1 cm² == x

x = 800W *   1cm² / 423cm² = 1,89W
a = 800W *  36cm² / 423cm² = ~68W (1x4) 
b = 800W *  48cm² / 423cm² = ~91W (2x2) 
c = 800W *  54cm² / 423cm² = ~102W (1x6)
d = 800W *  72cm² / 423cm² = ~136W (1x8)
e = 800W *  72cm² / 423cm² = ~136W (2x4)
f = 800W * 108cm² / 423cm² = ~204W (2x6)
g = 800W * 144cm² / 423cm² = ~272W (2x8)

30x40mm: ~23W/module
60x15mm: ~17W/module

then i calculated the resistance of the found element to check on what wattage i can do at what voltages:

U = R*I
P = U*I
→ P = U*(U/R)

(i added these *guesses* in the table above)

So I decided to go with the 70x15mm 24V model. and will update here if i found how this works out..

and for the first test setup i will go with the concept 12V→ 27W / module so definitive more then enough..

as power supply i will use a MeanWell GST280A48-C6P (reichelt) with an fitting connector (reichelt) to get a 5V for the controller i will go with a recom R-78HB50-05 (VIN: 9-72V) and for switching the power to the heating elements i will use IRLB4030PBF – MOSFET N-LogL 100V 180A 370W 0,0043R TO220AB and to drive this a BC 550C as mentioned in this nice article: Schalten und Steuern mit Transistoren III – Mit MOSFETs höhere Ströme schalten

so when all the parts arrive i can go on.. with building.

for the Controller i plan to write it in CircuitPython and run it on an adafruit ItsyBitsyM4. and maybe later add an LCD – or use a PyBadge – for now i just want to use the arduino serial plotter or similar with an second CDC-device enabled to log the progress and the flash-drive function of CircuitPython for a text-file with the temperature-profile. i have written a request in the adafruit CircuitPython forum if there are any PID controller things out there…