Members: Shashwati JhaGR, Rebekah HanUG
Advisor: Dr. Richard Martin
Today’s cell towers are large, complex and expensive, but recent advances in thin-film solar and lithium iron phosphate (LiFePo) energy storage will allow for a new class of small-scale communication infrastructure. In this project, you will use a combination of thin film solar panels, batteries and Long Range (LoRA) wireless radios to build a small scale demonstration sensing and communications platform with a tree-like structure. The platform will use a combination of solar power, energy storage, and a small neural network to provide image recognition, wireless mesh networking, and small device charging services.
You may view our GitLab repository here. In addition, here is the Google Drive folder to all of our Thursday presentations. In addition, here is the CAD model and BOM for our solar tree.
- Defined the goals of this project, with accessibility and self-sufficiency in mind. Our Thursday presentation is available to view here.
- Brainstormed what the solar tree would look like, as well as defining the electrical configuration of the tree. We came up with a 200 W 28S2P configuration so that our given battery pack would take 1.5 hours to fully charge (in perfect conditions).
- Thursday Presentation.
- Research materials for solar tree + established a new design.
- Set up GitLab repository.
- Create this wiki page! (Yay!)
- Progress through Onshape's CAD Basics course.
- Create block wiring diagram.
- Thursday Presentation
- Complete CAD Basics course.
- Verified the solar cells hold up in voltage in different conditions. In shaded conditions, it holds up at 0.63 V.
- Took the Woodshop 1 course to use the table saw at the Makerspace. In-person test pending.
- Here is our wiring diagram. In theory, this is what would happen if a string of cells were shaded. Since we are not getting any more solar cells, we will work with a 35S configuration.
- Successfully transmitted packets from the transmitter. The receiver was able to receive the packet, but it was corrupted. This is because the Adafruit bonnet (transmitter) was plugged into the same Pi that was receiving. The next step is to separate the two from overloading the receiver.
- Found out that we likely need to order new boards so that MeshCore can be flashed onto them.
- Somewhere around this time, finalized-ish our parts list to order.
- Thursday Presentation.
- MeshCore was also developed for a particular kind of hardware architecture, which is a board with a LoRa radio and an ESP32 or nRF52 microcontroller. The hardware we received did not have such chips. Finding that someone implemented MeshCore in Python, we tried to run it on our Raspberry Pi.
- Thursday Presentation.
- We really spent time breaking down meshcore-pi in order to have the program run on our older, SX127x transceiver. The code originally supports only SX126x models.
- Thursday Presentation.
- We resolved the transmission issue we had by adjusting the transmission power to be 13 dBm instead of 17 dBm. We were able to successfully send and receive messages!
- Thursday Presentation.
- 3D printed enclosured for the new hardware boards we got to flash MeshCore onto. We ended up ordering supported hardware so that this could be deployed as a repeater radio. Also, convienence.
- The CAD model of the solar tree.
- The PVC pipes were sawed to size, and a junction box was ordered to store the battery and solar charge controller.
- We anticipate on putting everything together hardware-wise next week as we are waiting for a few parts.
- Thursday Presentation.