This is another feature that I decided my bot has “gotta have”.
When the bot gets to the point that it is roaming the house on its own, I’m sure it will have some “bad behaviors” that I will want to fix, such as running into things that it should have avoided. When these things happen, I’m going to want to have data to know why/how it made a bad decision. I figure the coolest way to do this is for it to broadcast radio telemetry data every time it does anything.
So, the bot will soon include a small transmitter module which is connected to one of the serial ports in the PIC-brain. In the C code, I simply do a printf() statement whenever I want to send some telemetry.
Somewhere else in the house will be a receiver for the telemetry data. It will be tied to a PIC that receives/decodes the serial data coming from the bot, and displays/logs/forwards that data to [whatever]. I may start with a PIC that talks to a small LCD display. This would make a small, portable package that can sit anywhere in the house. And/or it could be hooked up to the serial port on my PC, if it’s necessary to log a lot of data.
The radio link works on either 433 or 315 Mhz. These frequencies are also used by things like garage-door openers and auto keyless-entry gadgets. So, it’ll be cool if my telemetry system can filter out “bogus” data that it may receive. Perhaps I’ll implement a simple ‘protocol’ so that the receiver will know if has gotten good data or not.
Another enhancement might be to make the link work 2-way (half-duplex), by adding a rcvr on the bot-end, and a xmtr on ‘base station’ end.
I know that there are off-the-shelf wireless solutions out there, but I don’t care . I want to do it myself, and I don’t want to have any “operating system” or “software drivers” on either end.
You’re a brave, brave man, Pete.
I had taken a peek at those buggers and had run quickly in the other direction.
For me, those one-package solutions are a somewhat-expensive lifesaver.
However, I agree.
If I had your 1337 haxxor skillz, I’d be doing it the cool way, too.
Now that is one heck of an idea. I understand where you are coming from in regards to making your own devices. Some may say ‘why reinvent the wheel?’ - well. it’s fun to make your own stuff!
This is one idea I would love to see roll off the Pete assembly line!
Today I got the ‘basics’ of the robot-radio-telemetry working.
It’s still in a prototype stage, at the moment.
On the bot, I’m using one of those little transmitter modules from SparkFun (they sell for about $6 each). It connects directly to one of the serial ports on the PIC-brain. In the C code, with just a couple lines of code I can send any string (or binary) data. In general I will send little messages like “moving forward”, “obstacle detected”, etc.
The receiver is a Microchip “PICdem 2 Plus” demo board, with an 18F4520 plugged into it, and a Microchip receiver module (SparkFun has rcvr modules also, and they’re cheaper, but probably lower performance).
The receiver module drives the RX input on the PIC. The TX output on the PIC goes to a regular serial port connection, so that I can see the received data on my PC. So the PIC really just receives stuff on one wire, and echos it out on another wire.
In the near future, I’ll use the LCD display on the PICdem board to display the received text, so the receiver can be useful when the PC is not powered up. The PICdem board also has LEDs and a piezo beeper, so I can use that to ‘sound an alarm’ if the bot gets into trouble, or whatever.
. I want to do it myself, and I don’t want to have any “operating system” or “software drivers” on either end.
, i wish i could do the same thing, but alas, even with perfect instructions i would more than likely break something 