I would like to build a small transmitter / receiver module and need some help.
I want to have a transmitter that will be powered by 12 volt vehicle source, it will have a switch that will put it in constant transmit mode when turned on.
The receive module will then turn on a set of led's when it receives the signal from the transmitter.
The idea is that as the vehicle drives along it will turn on the led's when in range they will light for 2 min and then turn off, until the signal is received again. Only need about 100 yard transmit / receive distance. The led's will be used to mark locations.
I was thinking of using some of the inexpensive 433mhz kits and arduino pro mini's but this is not my area of expertise and could use some help with this project.
This doesn't sound like a good idea at all. You seem to be relying entirely on an unknown variable - the signal strength, or the lack of it, of a moving transmitter. So what is the real objective? How far apart are the receivers? And who is looking at the LEDs? And why? By the way you describe it, you probably don't need Arduinos.
If you are serious about it, an Arduino with GPS in the vehicle might work well. It just needs to constantly check its position relative to the receiving stations, and send a coded broadcast accordingly. Who knows? you might even be able to dispense with the LEDs.
I might not need the arduino's you are correct i'm not sure but I figured I would to enable the timed off feature.
Basically I'm going to be placing these markers at specific locations that I need to check where equipment or sensors will be at. These will make the equipment easy to locate at night. I do not want to use gps because locations can change and I do not want to reprogram anything when the location changes.
The distances between the markers will vary from 100 yards to 300 yards and I'm looking at building like 50 of the receive modules. The receive modules will have a solar panel and battery onboard so once set up they will be maintenance free.
In theory the transmitter will be tied to the vehicles 12 volt system and will turn on when the vehicle is in drive. As I drive along at a speed of 25 to 35 miles an hour when I get within range of a receiver the signal will turn on the flashing LED's they will continue to flash for 2 minutes. I put the vehicle in park it disables the transmitter. I check the equipment move on to the next one.
Hope this makes more sense on what I'm trying to accomplish.
DesertFabworks:
I do not want to use gps because locations can change and I do not want to reprogram anything when the location changes.
The distances between the markers will vary from 100 yards to 300 yards and I'm looking at building like 50 of the receive modules.
OK. But, with distances like that, there are likely to be times when more than one receiver receives, but maybe that doesn't matter.
You may find Arduino IS a solution simply because it is cheap and practical, thereby making gross overkill irrelevant. Not necessarily Arduino per se, but a bare-bones custom-made device developed from Arduino. I imagine a production run of 50 makes this entirely practical, as well as the most economical.
This could be a ready-made solution -- a bare-bones ATmega328 Arduino compatible board with a radio transceiver, RTC and extra memory, for US$ 15. Anarduino MiniWireless Details
You would just need to program one transmitter to send a certain beacon packet, and the rest would listen for that packet.
I would skip the vehicle connections and just have a box sitting on the dash, with a transmit/standby switch. It could be powered by a 12V to 5V cigarette plug adapter.
Ah, there you go then, you should push his green button. One of the great things you learn about Arduino is that, no matter where you want to go, somebody has been at least part of the way before you....
I found the light unit I want to use. It is a pre engineer light puck that is about 5"x5" it has a battery pack small solar cell, leds, and a dusk dawn photo cell. It is designed to come on at dusk and flash the led's until it runs out of battery or the sun comes up.
I want to interrupt the circuit with my receiver module so that it only comes on when it receives the signal from my transmitter. So I want the receiver to basically be a switch. But I want that switch to stay on for 2 minutes each time it gets a signal then turn back off until it gets a signal again.
Not sure how to design or build that circuit. Seems like this setup for Adafruit might work, but their transmitter is very week and I would need to figure out how to create the on for two minutes part of it as well as the switch component vs the power to a pin.
You could probably add an antenna to the Adafruit keyfob, which would dramatically increase the range.
If you use the M4-type receiver, the light would be on for as long as the transmitter is on. Turn the transmitter off after 2 minutes. Or, use the L4-type latching receiver. Push the transmitter button once to turn on the light and once to turn it off, two minutes later.
Adding an antenna is an idea and eliminating the push button on the transmitter and making it an always on could work.
With the limited range it would only send the signal to the receiver when in range, when it leaves range it would turn off and I would not have to worry about a timer.
When I got in range the LED's come on and stay one while I work. When I leave and get out of range they turn off. Should be no problem to print up a new case for the transmitter. I really want to hook it into the vehicle 12 volt system not sure what that transmitter is running on but should be possible to make that happen so I dont have a battery in the transmitter and can use the 12 volt from the vehicle with an on and off toggle switch.
With the receiver from adafruit it allows power to go to the led to turn it on when it receives the signal from the transmitter. How would you wire it up so that instead of sending power it allows power to flow through the circuit which already exists in the light unit?
Thanks again for all the ideas this is helping i'm getting close!
The light diagram should be very similar to this diagram. With a solar cell, battery, leds, and photo resistor for dusk dawn. I want to keep the circuit intact except basically insert a remote on off switch. So I was thinking of hooking in either on the positive or negative side of the led but not sure how to accomplish this.
I would need the receiver unit from the adafruit to be my on and off.
I know nothing about electronics or circuits and I'm trying to self teach with about 2 days of learning.
Would this work: In the solar light circuit. cut the positive lead before the led put that to the +5v on the adafruit receiver connect a wire from the LED - side to the receiver ground. Then connect the + side of the LED to the D1 pin on the receiver???
If I have this right when the sun goes down the photo resister allows power to flow through the circuit to the adafruit reciver. But the LED does not light until the receiver gets the signal and then it completes the circuit allowing +V to go to the D1 post.
If some people that know circuits could check this idea and let me know I would appreciate it.
I was planning on using the solar light to power the receiver. The design may be a little different than the one shown. I may have to put the receiver in-front of the led resistors so that the receiver can get its 5v The power supply may also have to be adjusted a little as well as some of the resistors to make it all work but, I'm hoping that in theory this will function the way I have it envisioned with a few adjustments.
jremington:
[u]This could be a ready-made solution -- a bare-bones ATmega328 Arduino compatible board with a radio transceiver, RTC and extra memory, for US$ 15. http://www.anarduino.com/miniwireless/[/u] You would just need to program one transmitter to send a certain beacon packet, and the rest would listen for that packet. I would skip the vehicle connections and just have a box sitting on the dash, with a transmit/standby switch. It could be powered by a 12V to 5V ecigs plug adapter.
Well it seems like ready made solution.. I am working on similar project so your advice will really help me out..
