| Oct. 7th |
|
Writing this Tues. 11th, trying to get back on track here; I had a week
with a nasty cold, then a deadline for my internship at MGH that really
snuck up on me.
Despite my lack of updates here, I have been finding the time to pick away at this project as much as possible. I've been mainly frustratingly trying to figure out a good design for the VLF/audio input stage. I was originally going to use a digital switch to route either VLF or audio through the same preamp, but was running into impedance problems, and I'm thinking now, after some experimenting, that the VLF preamp will need much higher gain using such low voltages (most of the VLF designs I've found are powered by at least 9 volts). I then tried this design:
I also received an order of parts the other day, including a buck/boost converter (hopefully I'll be able to use a single 3.3v supply, a DHT11 digital temp/RH sensor and a couple thumb-joysticks and 5-way tactile switches. sensor |
