Today, we finally did a range test on the 433MHz Emergency Stop board I made.
The minimum range the project is looking for was 50ft, reliably. The good news? We managed that distance no problem. Better news? The range is so far we're not sure how to appropriately measure it.
Indoor's where you expect reception to be worse. We left the transmitter in our lab and walked away with the receiver to a point in the building we could not receive the signal anymore.
This ended up being about 150 feet, through the doors of our lab (which have been known to be pretty impervious to RF), not even close to line of sight, and while transmitting at the lowest voltage possible.
Next up was an outdoor range test, again plugged in to an outlet at one building the transmitter was left to transmit. The receiver was walked behind buildings and a range of about 200ft was managed, although it could probably go further.
Finally, we did a Line of Sight Test, One person on one side of the parking lot, myself on the other side. With line of sight, we've easily managed 450ft. Just 9 times the required distance for the E-stop. Thats with the 3.0V minimum transmit voltage (works up to 5.2V).
Later this week we will test using a different method. Namely find a dead end road and drive straight down it until we can't receive anymore, and try this with the higher transmit power, also.
I'd bet we can get over 1000ft out of these things if we try.
Ill put up pictures of the schematics and a parts list for those interested in this. ~60$ gets a reliable link up to about 1000ft (Data sheet says you can get 3000ft if you know your RF design...I don't). If your looking for simple switching, this beats the price of Xbees.
No comments:
Post a Comment