I am working on a project and need some help. My son has a room with no outside walls (no windows). I have made a virtual window to hang on the wall with leds for light I have a light sensing device (schematic below) that bring the lights up as the sun comes up and down as the sun goes down. I would like to have the sensor outside (on balcony) and transmit the light level through 1 window, 1 wall and 40 foot to the window without wires. I have been thinking about this for some time.
I haven’t programmed any pic microprocessor but with some help. Could I use the a pic microprocessor to covert the analog signal to decimal, a TLPA and RLPA TX/RX from http://www.sparkfun.com, and another pic microprocessor to convert the decimal signal to PWM to light the leds? Or is there a better Way?
What examples close the to these things are available to look at?
Some of the new atomic clocks have remote temperature sensors could I hack a $20 clock and use the tx in that… No way. I just don’t know how.
That is such a great idea to have a virtual window for your son–very cool. Your suggested approach sounds very suitable to me.
The PIC will convert the analog signal to digital, then you can transmit the digital info to the receiver via the transmitter/receiver pair you describe. At the other end, the received signal could light the LEDs using the PWM function. Basically just what you said!
There are lots of code snippets out there that will do it; let us know if you need help piecing it together or code or whatever.
Thanks Jeff, I do need help and I hope this makes since
I am not sure if I understand this all but this is what I think I understand.
· Starting from the light sensor the light level is turned into a voltage.
· This voltage is sent to the analog to digital converter in the microprocessor and converted to a binary number. So, I now have a binary number with ? bits. (Not sure what is needed.)
· This binary number is coded with special stuff before and after.
· This bunch of 1’s and 0’s are sent out the TX.
· At the RX, It is getting all kinds of stuff. It’s coming in from everywhere but the microprocessor is looking for our special stuff with the binary number and more special stuff.
When it gets it and it’s sure.
· The binary number is removed and is held in the microprocessor
· This number and some magic, outputs to the led and makes then light the same as the light sensor sees.
· I think I have some of the magic figured out. Pulse Width Modulation.
Is this how PWM works?
I have to talk movies for a moment. The film goes through the camera at around 25 frames each second and the picture looks smooth. So my thinking is that if I could break time into 1/25 of a second the light would be smooth also. Don’t laugh it’s all I have to relate to at this point. Now If I could turn on the light for part of each 1/25 second this would make the light go brighter with more on time and less light with more off time.
http://www.crouchman.com/tx/getLight.jpg