Think, Suggest, Advise

Help investigate how best to integrate the sensor system with beehives. Currently we have two concepts on the table. The first is to distribute our sensors around the hive and connect them with wires. The second is to integrate all our sensors into a top bar frame sized container, from where they will monitor hive conditions.

Please share any thoughts or ideas you might have below.

I know the idea of 3D printing a case was kicked around. I think a laser cut case made of acrylic or plywood would be easier to design/make. I'd like to take a stab at the design.

Can those working on the sensors describe the specs that would be needed?

Hey Patrick,

Continuing with @jonathan's interest in developing a top bar & frame with integrated sensors, I recommend we design and prototype something that can be inserted between top bars. Jon should be able to put his images and ideas in this thread shortly.

In the meantime, it would possibly have the following features:

• Comb is generally between 20.20 mm and 22.60 mm thick (source)
• Bee space - the space between combs - should be around 9mm (source)
• The case should be a box shaped like the interior of the hive that attaches to a top bar or that has its own top bar replacement.

Questions

1. How thick should this sensor box be? It needs to allow for wire leads to plug into the bread board.
2. How will the breadboard/MCU mount to the box interior?
3. How will the sensors mount to the case?
4. How many holes do we need and of what sizes? (ventilation, power cables, etc.)

I'm interested in what other people think. Did I capture our thought process correctly?

Thanks Patrick

Maybe I'm behind on the design here, but has the precedence been set to use wired sensors? Or wireless?
If the space for the sensor and housing was routed into the top bar, that would allow the most usability and a modular type system to move the sensors anywhere in the hive to get results at different parts of the hive.

A system that just gave readings on the weight of each frame would be a data point I'd be interested. It could give researchers an idea of the honey to brood ratios as well as day to day traffic patterns which is an excellent indicator of health. It would have the added benefit of letting hobbyists know when it was time to add frames.

I would choose higher fidelity sound monitoring over weight of frames though. What about a weight system that ran the length of the hive underneath the frames on the lip of whatever the frames rest on. It could easily connect to the "frame" that houses all the other sensors.

For Langstroth hives, a sensor system integrated into a slatted rack might be an option. Those would fit well in an awful lot of commercial hives.

We've started with wired sensors, because that's the most straightforward path. It's possible we'll use multiple wireless sensor nodes in the future that communicate via Bluetooth LE to a central microcontroller that broadcasts data to our servers via wifi. More to come, but yes, it's all wired at the moment.

Colorado Top Bar - v6.1 - Interior Dimensions

Note: The vertical height from the bottom of the hive to the bottom of the top bar is 8.76".

CTB - v6.1 - Top Bar Dimensions

Note: On the right, the 0.27" dimension refers to the space between the comb and the outside edge of the top bar. This is based on an average comb width of 20.20 mm (source).

Colorado Top Bar - v6.1 - Alpha Kit Sensor Case Dimensions

• Top: 17.77" / 451.358 mm
• Bottom: 7.10" / 180.34 mm
• Sides: 10.12" / 257.048 mm
• Width: minimum 3" / 76.2 mm

Determining Width Requirements

• Bee Spacing: 0.27" x 2 = 0.54" / 13.716 mm (source)
• Breadboard: 0.33" / 8.5 mm (source)
• DHT22: 0.988" / 25.1 mm (source)
• Standoffs: .375" / 9.525 mm (source)
• Wall Thickness: 0.125" x 2 = 0.25" / 6.35 mm
• Total: 2.533" / 64.34 mm

Alpha Sensor Case - 01 by on Sketchfab

Critique of v0.1

1. The model above doesn't allow for bee spacing. Currently, the top and bottom pieces pass through the side walls. It needs to be the opposite way - the side walls need to pass through the top and bottom, and the top piece needs to be wide enough to account for bee space.

2. There's a gap on the left side at the bottom for some reason. It's not wide enough.

Re: Preventing RFI
(see this thread elsewhere in the forum)

If this box is inserted at the entrance of the hive, the case's back side, which faces the brood, could be shielded, and the front face would be directed towards the wifi router. So, the front of the hive would need to face the wifi router.

Incredible Schematic

• The black box is the CTB
• The yellow area is the majority of the bee colony
• The orange box is the sensor case
• the red line is the shielding on the back of the sensor case
• the green arrows are the wifi signal
• the blue box is the wifi router

If you shield the box completely, you defeat the purpose of putting the case inside the brood with a drop in design, because you can't broadcast your wifi. We should look at antennaes that can be mounted outside the hive - this came up with my discussion with Caleb today.

This design looks great - it looks as though it could be quite easily laser cut, though that brings up questions about materials again!

As for bee space, if we place the sensor bar at the front of the hive, bee space would likely only be a consideration for the inner facing wall. The outer facing wall could probably sit right up against the front section of the CTB. Of course we need to make sure there is room under the structure for bees to enter the hive.

Apparently this TF200 Thermo is pretty good at insulating against Wifi and other signals.

READ MORE HERE

Here is a (very rough) alternative design for an in-hive sensor container.

This design uses a u-shaped wooden frame, with mesh stabled on either face to sandwich the sensors inside. Supposed benefits might be easier flow of air through the container to more accurately measure humidity and temperature, though I'm not sure if the mesh would allow for accurate readings within the sandwiched space.

In this design, the sensor hangs independently from a top bar within the frame.

Feedback encouraged for either option!

CTB Entrance Dimensions

Barcelona Warre v2.4 Entrance Dimensions

Length: 3.149" / 80 mm

Height: 0.378" / 9.61 mm

Alpha Kit - v1.0 - Case Design

Introduction

The first design will be for the Colorado Top Bar. After testing, it will be modified for the Barcelona Warre. The case will have the following features:

1. Acrylic material - probably 1/4"
2. Snap-fit design
3. Prototyped on a laser cutter
4. Follows the interior contour of the hive
5. Drops in place like a normal top bar
6. Preserves bee space on either side - 3/8"
7. Maintains space at the bottom for bee movement beneath
8. Uses cable glands to allow wires to pass through
9. Uses holes for air ventilation for temperature & humidity detection
10. Uses standoffs to mount a perfboard as seen below
11. Is mounted at the front of the hive by the entrance taking the first slot
12. Uses the TF200 Thermo insulating membrane on the brood-facing wall to minimize wifi disturbance
13. Uses an exterior-mounted wifi antenna to concentrate radio waves in one area and away from the hive core.
14. Displays the Open Source Hardware Logo and/or OSBH logo in a prominent location as an engraving

Sensor Kit Mounting

Alpha Kit - v1.0 Schematic

The IR counter is nearing the testing phase. It will have its own case.