This week we spent the majority of our time on PCB design finalization. We made some design changes with regards to ordering an MQ-02 sensor with a built-in breakout board as well as a potentiometer to ensure that we wouldn’t have to waste time recreating this circuit on each node. We also added the possibility of powering our board with a barrel jack and ordering a plug to show how when attached to a wall, we would be able to power our nodes when they are not just running on the batteries. We also started working on our final presentation slides and cleared up some concerns with regard to the content of the presentation and we are now working to reformulate it in a manner that we can show off the progress we have made up until this point despite being able to keep working on it after the presentation.
One of our major risks is ensuring that the PCBs come in time and are wired correctly. We have spent a lot of time this week connecting with Quinn and learning how to use the Voltera to make our own PCBs which we started two versions of but had to edit due to the trace width or spacing between holes/pads as the conductive ink tends to spread when the probe moves. Even then, the machine doesn’t have big enough drill bits for our mounting holes so we had to order that which means we can only clean up and finish our PCB on Monday. Quinn was nice enough to order our PCBs on Friday through JLCPCB in order to have a backup plan using a design that Aidan and Neha spent a lot of time checking for correctness. Though we are hopeful that it will work as intended, we want to be able to anticipate it not working the way it should, in which case we would need to edit the design and send them out to be fabricated once again despite cutting it close in terms of time. We are also considering the possibility of using solderable breadboards to get a slightly more finalized version if all of our PCB fabrication attempts don’t work out.
One other risk is finding the correct voltage for our wall power supply. We know that we are able to use at least a maximum of 7V on the 5V rail of the ESP32 and we need at least 5V to our batteries after the diode and resistor in our circuit. This means that we should be able to get a high enough voltage to our batteries, but we still need to find what value we will use.
The only change we have to our schedule is that we had to push back some of our deadlines such as the poster, video, and creating the shelf for our demo. In hindsight, it was probably a mistake to schedule these as early as we did because we need to have a working product before some of these tasks. However, we feel that we will be able to finish them soon and before the actual deadlines, so rather than actually changing our schedule, we will just catch up in these areas. We also received notice that we have been invited to present our demo at the general CIT presentation, in addition to the general ECE one, which has moved up some of our deadlines, but we still believe that we will have enough time to get it all done. After this upcoming week ends, most of our schedules clear up, allowing us to dedicate more time to get things finalized.