need a cheap short range transmitter receiver using a PIC as trigger to transmit a signal 75ft in a closed room. Just need to trigger an LED on/off by wireless from one transmitter to 12 receivers.
A simple 1 transistor circuit might work but thinking an output pin could be used as an oscillator to an antenna?
some schematics I found on web. maybe too simplistic?
NO voice communication, just a trigger pulse from transmitter to te 12 receivers that indicate a signal has been transmitted.
found the MAX1472 and 1473 but could get expensive with one transmitter and 12 receivers.
Only need a 50 foot radius. 30 feet would do it but margin for error.
doing a web search for say a 555 receiver or ??
I hack a lot of gunk for parts and as I said I have seen 433 mhz transmitter and receivers that are just a 8 pin pic and maybe
4 parts coil crystal npn variable cap. and have 50 to maybe 75 foot range.
Am thinking of a sound trigger is a possible solution. A very narrow bandpass filter athat accepts only say 15khz?
Might be easier than going RF
$2.34 to make my own??
A different wireless possiability?
May be cheaper than going with the max1472/73 combo Wireless Doorbell
if you got to Wireless Doorbell and go to transmitters on P3 they have actual pics and a descripytion of wireless doorbell.
havn't seen what some of the coils are. Blind in one eye can't see outta the other. need to sit down and figure out how much each unit will cost.
Only need one transmitter and 12 receivers
After much web browsing, **broken link removed** seem viable for some simple comms with a smaller size micro. Cheap enough for sure, so picking up a few to play with. After much frustration with the microchip zigbee modules, the Nordic modules should be a breeze to communicate with.
The Nordic modules are designed for use within the ISM band for very short range use, so not a chance of reliable 75' radius.
Look for something along the lines of RF Solutions FM Modules.
Normally I would say two tin cans and a bit of wet string, however 75' reliably to a dozen receivers is just out of range
The Nordic modules are designed for use within the ISM band for very short range use, so not a chance of reliable 75' radius.
Look for something along the lines of RF Solutions FM Modules.
Normally I would say two tin cans and a bit of wet string, however 75' reliably to a dozen receivers is just out of range
In my experience 2.4Ghz blows badly for distance compared to 900Mhz and 433Mhz, especially indoors.
RFM12B/RFM12BP if you want something digital. Otherwise, I hate those bit twiddle modules, but they would work fine in this case. Nigel has some tutorials on them. You'll need proper encoding.
I didn't say they won't hit the 75' mark, they may well do so, merely that I doubt that you will achieve reliablility at that range. Those particular Nordic modules are designed for use with wireless keyboards and mice which is very short range. The Microchip devices may also hit 75' as stated by wannaBinventor, however I have no practical experience of using them and therefore can't comment on their suitability for your application.
The Nordic modules are designed for use within the ISM band for very short range use, so not a chance of reliable 75' radius.
Look for something along the lines of RF Solutions FM Modules.
Normally I would say two tin cans and a bit of wet string, however 75' reliably to a dozen receivers is just out of range
When it comes to RF and antennas I couldn't tell the difference between rubber gasket and a wet cheerio, but I am using the NRF24L01 in a commercial product and get about a 300' range on it. The antenna on our board is straight, not bendy like the one on the module. I have NO idea how much of a difference that makes though.
**broken link removed** <-- This one was returned... love the microscope