chip updates: going the current sensing route & EMI [updates]
I think this is the last thing we're going to have to spend money on for this project... hopefully.
So after watching the OpenDog's last video about trying to add force sensing to the feet. In the end, James talked about how because of the motors, the signal was really spiky from the force sensors on the foot-it was basically unusable due to EMI. This leaves us with a few considerations.
So as you know, we're using an ArduPilot to as an IMU and things like that. It also has a GPS/Compass sensor mounted close to some motors which could be affected. These sensors have an in-built EMI Interference Calibration. We probably won't run it now because we just need IMU data, and we'll see how accurate that is with the EMI on, but I don't think it will be too too bad, these things are built to filter out quite a bit of EMI, and we can always put some copper shielding underneath if need be. The shielding will help block any EMI.
But this is another great argument for using current sensing on the motors. If we sense the current going into the motors and transmit that back VIA CAN-BUS, there's no room for interference, and it is much less likely that these measurements could be skewed by environmental factors.
Just to block out most EMI from the comms, telemetry, and processing systems *because it isn't great for it anyways* we're going to get this: https://www.amazon.com/gp/product/B01HPGXBR0/ref=ox_sc_act_title_1?smid=A2YE6R85UF3M12&psc=1
Which is copper shielding cloth, and we're going to get this:
Which will tell us exactly how effective the cloth is being (hopefully). I kind of want to test this.
Feeling a little like NASA here :) Read this! https://www.nesdis.noaa.gov/content/good-gold-are-satellites-covered-gold-foil