A single unit should cost about 80€, parts will include:

• housing
• fan(s) 12V or 24V, some candidates: AFB1224HHE-T500, MS1238E12B-FHR-2EM, AFB1224SHE-T50F, = order the fan from DigiKey!
• active carbon filter
• prefilter(s)
• hepa filter
• motor speed controller
• 12V or 24V power supply, external, sealed

This parts are here to document the design process, the final BOM and results are below.

Item	Picture	Description	Qty	Unit Price	Total Price	Link	Comment
SC120-W5		Metallic fan protection for 120mm fans	6	0.6€	3.6€	link
AFB1224HHE-T500		120x120x38mm fan 0.354 in H2O (88.2 Pa)	1	24.34€	24.34€	link
MS1238E12B-FHR-2EM		120x120x38mm fan 1.200 in H2O (298.9 Pa)	1	26.70€	26.70€	link
AFB1224SHE-T50F		120x120x38mm fan 0.571 in H2O (142.2 Pa)	1	24.93€	24.93€	link
Motor Speed Controller		5A 28V motor speed controller	1	8€	8€	link
F8 / F9 Feinfilter matte		Filtermatte F8 or F9	1	16.8€	16.8€	link
Active carbon 1kg		Active carbon for bad smell	1	9€	9€	link
Pre filter G4 matte		Filtermatte G4 for prefilter	1	10.85€	10.85€	link
Hepa TE70TE15021 Hoover		Hepa Filter	1	5.5€	5.5€	link	18x98x108mm, 190cm3, sealing on the bottom, seems easy to attach
Hepa Bosch BSA		Hepa Filter	1	6.4€	6.4€	link	11.8×132.5x96mm, 150cm3 sealing on top, side plastics makes it difficult to attach
Hepa Zelmer ZVC		Hepa Filter	1	6.7€	6.7€	link	21x108x98mm, 220cm3, sealing on the bottom, seems easy to attach
Hepa Ariete 2741		Hepa Filter	1	5.4€	5.4€	link	19x104x96mm, 190cm3, sealing on top, seems easy to attach
Hepa Electrolux T8		Hepa Filter	1	5.4€	5.4€	link	21x88x103, 190cm3 sealing on top, side plastic makes it difficult to attach
Hepa Siemens VS		Hepa Filter	1	9.9€	9.9€	link	32x95x82mm, 250cm3 sealing on top, side plastic makes it difficult to attach
					160.52€

• Fans in series increase the pressure but keep the same airflow, fans in parallel double the airflow but keep the same pressure
• 120x120x38mm fans seems the best format
• some fans are highly dangerous for the fingers, maybe better to protect the front/back with a plate!
• fans could be only with 2 wires and voltage controlled; the 5A motor controller seems ideal and cheap: https://www.amazon.de/-/en/Gebildet-Controller-Adjustable-Reversible-Regulator/dp/B07X5JZX4M/ref=sr_1_13?crid=39BGVBV3X1336&dchild=1&keywords=motor+speed+controller&qid=1629811356&s=diy&sprefix=motor+speed+c%2Caps%2C161&sr=1-13
• fabulaser filter is: G4, F9, H13, Active Carbon
• Weller soldering filter is: F5 + E12
• firtermatte could be precut or cut by hand
• the hepa filter maybe taken from a vacuum cleaner filter https://www.ebay.de/itm/373462598006
• do we need a middle size filter (middle size of the dust)? in case we can cut it from some “taschenfilter”
• Similar push structure as Fabulaser Filter + rubber/foam tape?
• noise isolation material for the fan?
• if everything is powered by less than 48V then it should be categorised as low voltage device (for CE certification)

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Total cost is about 60€

Item	Picture	Description	Qty	Unit Price	Total Price	Link	Comment
MS1238E12B-FHR-2EM		120x120x38mm fan 1.200 in H2O (298.9 Pa)	1	26.70€	26.70€	link
SC120-W5		Metallic fan protection for 120mm fans	2	0.6€	1.2€	link
F8 / F9 Feinfilter matte		Filtermatte F8 or F9	1	0.5€	0.5€	link	Here a 120x120mm piece is needed, price is calculated accordingly.
Pre filter G4 matte		Filtermatte G4 for prefilter	1	0.5€	0.5€	link	Here a 120x120mm piece is needed, price is calculated accordingly.
Active carbon 1kg		Active carbon for bad smell	1	9€	0.9€	link	Here less than 100g are needed, price is calculated accordingly.
Hepa TE70TE15021 Hoover		Hepa Filter	1	5.5€	5.5€	link	This is usually used in vaacum cleaner.
6mm Wood Sheet		6mm Poplar Wood	600x400mm (approx)	5.8€	5.8€	link	Also another kind of light wood would do it. MDF is not recommended.
4mm Wood Sheet or MDF		4mm Poplar Wood or MDF	250x250mm (approx)	3€
PLA Filament		Normal PLA filament	100g (approx)	2.5€	2.5€	link
Cable Gland		PG7	1
Superglue			1
Power Supply		12V 5A or more	1	15€	15€	link	Needs to be a power supply of the type that does not need an enclosure.