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remo²hbo Hardware: Casing
Durability: instrument must be shielded against moisture, water, fine dust particles, and high temperatures. The following conditions apply:
| Parameter | Unit | Constant operation | Tolerance (30 minutes) | Transport | Notes |
|---|---|---|---|---|---|
| Temperature | °C | -5 to 50 | -10 to 60 | -10 to 80 | |
| Moisture | % | 100 | 100 | 100 | |
| Water | m water column | splash water | rain | splash water | |
| Dust | particle size and particle per cubic meter | all particle sizes, high exposure | all particle sizes, very high exposure | sand storm | fine dust particles and sand, sand storms |
Resilience: instrument must be shock-resistant.
A 1.5 Liter angular plastic bottle with rubber rings for mounting. A mounting ring is fastened to the inside of the bottle (in my prototype with adhesive tape, but silicone would be preferable).
A panel is attached to the cap using 3 mm screws.
The foot at the bottom of the bottle contains a steel spring, which provides the panel with loose stability in order to absorb shocks.
The plate that I used has two openings/spaces for 5x/ cm perforated plates. A RasPiB would also fit.
A button is attached to the edge of the plate and can be pushed through the plastic.
The NeoPixelLED is visible through the plastic. An OLED is also feasible to display heart monitoring etc.
- Plastic bottle only costs 0.25€ deposit. Replacement can be found in many countries very easily.
- You can find small plastic bottles with large openings on the Internet starting at about 1€.
- In addition to the plate etc (I can only estimate about 3-10€) and the silicone glue which would be required for any changes, we only have a few euros in total costs per casing. Ideally, we would have one casing type for everything.
- It is unique, robust, cheap, lightweight, and can float.
- If containers are needed for transport and drop-off on site, these containers could also serve as replacement casings:
- Bandages, medicine, small instruments, operational equipment, etc. are packaged as shock-resistant and waterproof in plastic cans. Many similar plastic cans are bundled.
- In case of bad landing, only outer plastic casings are damaged, while RasPis etc. remain intact.
- If everything arrives intact, you also have a plastic operating table, urine sack, soup cups -> multiple use.
- All sensors are attached without plugs:
- Optional and better for fast servicing, connect/attach/glue the plugs on the inside.
- Several cables with sensors are then attached to the bottle: this is cumbersome in practice, but otherwise robus and cheaper. Thus, the handling in the field should be tested.
- For necessary cables:
- Ideally just one type of cable, in order to reduce spares inventory
- For necessary plugs:
- have a usb-plug protrude from the casing on a cable
- if this part is defect, a new cable can be soldered/glued in
- Which parts must be contained in one unit? (power supply only or battery pack as well?)
- Isn't one ESP32 per patient enough, which would be smaller than an Arduino?
- Is natural cooling sufficient? (direct cooling is not possible; A metal insert would make sense for water cooling...=more challenges)
- Which plugs can be avoided?
- Can globally available cables be used? (e.g. USB or CAT5 patch cable…)
Instead of plastic bottles use clip-and-close cans: - slightly more expensive at ca. 3 €
+ no silicone/glue for opening and sealing necessary
+ more stable
+ more sizes available
+ stackable
+ boards can basically be attached with regular distance bolts
Wouldn't a Pi zero be sufficient? + reduce costs
+ reduce power usage