First off, something fun (if you’re boring like me)
I decided to record data in my car overnight and through the daytime. From 12:00am to 7:00pm thereabouts. I recorded the data every 4 seconds with the following sensors
- NTC Thermistor
- Low Sensitivity CDS (Resistor that changes when light hits it)
- High Sensitivity CDS
- Accelerometer X,Y,Z axis
Why did I do this? just cause. here is the resulting chart
Here is the legend: B = Temperature , C = Low Sens. Light, D = High Sens. Light, E = X axis accel, F = Y axis accel, G = Z axis accel.
All of these values are as the MCU read them, ranging from 0-1023. They are also logarithmic so as they approach 1024, the value is ‘squished’ so large changes appear small. anyways, I thought it was neat to see the following things occur.
- Temperature of the device goes down as the night wears on. There are some lights detected, probably people passing by in the alley behind my car. some drift is noticeable from the accelerometers (due to temperature change?). Also something to notice is that X and Y are pretty much the same
- The light appears to go haywire, this is me driving in the dark and going under streetlights. Also, the temperature increases, the accelerometers shake and show the duration of my drive to work.
- As my car is parked you can see that I have parked crooked by the X and Y axis. Also, the sun starts to come up. As far as I could tell, it was pitch dark outside, the sensitive light meter says differently.
- During the day, the overcast sky keeps the sky about the same light level, whereas with the less sensitive instrument, since it’s further from saturation, shows variations in the ambient light level through the day. Temperature also fluctuates.
- The Drive home, very similar to the drive to work.
- The car is level again and the light level drops as well as the temperature.
Anyways, I know it’s boring but it’s neat to see real world events (ones you didn’t know about) show up on the chart.
Update on the Digital Gage
Things are proceeding apace with this as well. The rail and the encoder are attached together and they also slide together with the aluminum part I machined for that purpose. Now as for the board, this was a nightmare. Nothing but problems. I started out with a PIC18F46K80, the faster/cheaper versions of the high end 18f4680 and initially it was all OK. Until I tried to use the UART. For the life of me, I could not get the UART to stop spitting out junk. Once I started getting it to stop spitting out junk, it then output nothing at all. 🙁
Now, I’ve switch over to a standard 18f4680 but the LS7166 is giving me problems. aaargh! Anyways, things should improve with a bit of hard work and a fresh mind on the idea.