Bergen STEM Amateur Radio High Altitude Balloon (ARHAB)

ARHAB Blog 3/29/19 -        Add Clearance (1/2mm-1mm) to top and bottom where components meet -        Increase height of treads on door/Print better gear -        Possibly combine two larger components into one -        Add additional two switches and add holes for mounting and (1.5mm-2mm of travel to engage switch)  -        UChannel for feeding wires to circuit board? -        Extend end so the door doesn't need to close at the perfect spot Latest Design:

We discussed how we are going to mount the new petri dish modules onto the payload. Instead of using the polycarbonate or aluminum rods, we are looking into using carbon fiber tubes, which on paper should reduce the weight of the payload while providing stronger support for the modules. https://www.mcmaster.com/2153T86 Additionally, we are considering reinforcing the modules in a similar fashion to that of a suspension bridge. Our running idea is that a loop of string, twine, nylon, or some other strong cord will run across both sides of the box and through holes in the corners of the modules. The cord may be knotted around the holes in the module to keep it from sliding out of place. This will provide result in trusses that may help reduce the likelihood of the modules bending downwards or upwards. We also regained our circuit board and are reviewing its programming. We also found the data sheets of each module for implementation.

Comments on Petri Model: Dish compartment height right now is 20 mm, which needs to be increased to at least ~20.5 mm because the dish itself is 20 mm. Add hole for the wire of the servo to travel under the Base/Holder and into the box Possible sources of weight reduction: Smaller, lighter batteries? (Old ones are just so heavy, maybe we can find lighter ones.) Carbon Fiber? - only circular rods are available but this can be adjusted in the model.

Review the collection assembly specifications and modify them so the cover and petri dish fit together properly Reorient the assembly so that the assembly support rods are perpendicular to the support rods passing through the box (realign the mounting screws and holes..) --- Will we need a new box for this? Or can we reuse previous box? Consider using aluminum rods through the payload box and metal screws and bolts to hold everything together. Reprint anything that needs to be rebuilt. Bigger base that fits the petri dish (Deeper, hole wider...this has been done on Fusion) Gear needs to be looked at (entire sliding mechanism) Bottom rails will need to be adjusted Review the software line by line to make sure that it is doing what we want (Kassem , Sadik, me, any other person who wants to join the software team…) Insure that the s/w converts voltages recorded into usable units and make sure that we know what those units are… Review the new circ...

9/21/18 Petri parameters; Wall thickness: 2.1 mm +- 0.1 mm Height including ridge: 20.0 mm Diameter: equal to fusion model but might need more clearance for easier inserting Old polycarbonate: 0.490"x0.400" Ordered full 1/2'x1/2" rods in polycarbonate and aluminum as well as a smaller size aluminum rod. 10/12/18 Materials came in and at the moment the smaller aluminum is appearing to be our go to rod-material. Reorganized the mess that came with moving rooms. All is now is in separate bins. 10/19/2018 The team met with Professor Balzarette and discussed materials and overall weight solutions. The idea of carbon fiber tubing came up for a possible more rigid and light material than the polycarbonate or aluminum. The batteries take up a lot of space and weight so we need to look into finding a solution for this.

We are almost finished with the payload. We finished the petri dish holders and cut holes in the box for the rods. We are did a mock assembly of the payload in order to weigh everything en masse. The payload weighs 8 pounds.

We finally have one of the compartments for the Petri dish. Unfortunately, it seems to be a bit too small, so we might need to either enlarge and reprint the model or file a few things down. The dish does fit if its pushed into place using a bit of force. Due to the way the holder was designed, the dish can only fit if its pushed in. The dish is essentially like a trapezoid (a bit like so \__/), thus in order for it to fit, the larger top side has to be pushed through the smaller bottom side of the holder. The motor mounts and the cover are being printed. We also finished the invitation form and sent it to Louis.