Calling you electronic genuises - fun project

[dmurray14]

I'm trying to replace an hardwired irrigation network (30 valves or so) with a completely wireless one. Going wired just doesn't work well - wires get chewed up, cut up, or just degrade, and it's a major undertaking to replace them. So, I'd like to do something with wireless. So far what I'm thinking is a system with a rechargable 12v battery and solar panel at each location, along with a wireless recevier. When the receiver gets a signal, it will power the valve open (usually running for ~2 hrs). I just can't figure out what to use for the wireless portion - does anyone know of a wireless transmitter/receiver cabaple of transmitting to 30 different devices individually? Any other ideas or input is appreciated!

Thanks,
Dan

 

[harrkev]

We have the technology... We can build it... But at what cost...

Wireless data transmitters and receivers are available, but at a price. Expect to spend at least $100 per unit on just that. For the radio portion, you will need to get a generic radio modem, and program a processor to decode the data. Here are some manufacturers, but not necessarily the cheapest ones:
http://www.data-linc.com/plantlinc/
http://www.radiodata.co.uk/Products/rdt-data.htm
http://www.elprotech.com/elpro/405.htm
http://www.intuicom.com/

Most sprinklers operate off of a solenoid. Power will be your big problem. It will take some battery juice to hold the solenoid open.

Expect to roll-your-own here. You will need per sprinker or zone:
(note that my prices are ball-park estimates)
1) Wireless receiver - $100
2) Large rechargable battery. Probaby a gell-cell would be the best - $20
3) Microprocessor to receive and decode the wireless data. A "Pic" or "Basic Stamp" should be OK - $40
4) Solar Cell, fairly large to recharge the battery - $40
5) Solenoid valve - $10 (you may already have these).
6) Some sort of plastic or metal housing to protect this stuff from the weather - $20.

So far, we are up to $220 per unit. So the grand total will be $6,600. This is assuming that you can find a radio receiver for $100. You will also need wire, perf-board, caps, resistors, etc.

Have fun!

 

[dmurray14]

thanks for the reply. I was hoping for something a -bit- more turnkey, but if I have to improvise, I will. The receviers are the big deal now - I'll have to see what else I can find out...

Thanks again,
Dan

 

[J0hnny]

He's right. I've looked into this before and it's crazy expensive for a hobby / private project.

 

[Colt45]

A PIC is like $3, not $40.

I'd probably rig it with remote-control car servos somehow.. they're cheaper.
I guess servo is wrong word.. i thought RC cars had servo motor + reciever one piece?
must be seperate.


I suppose you could make your own AM recievers, spaced out 5KHz or something, and have the PIC make sense of whatever you're transmitting via an ADC deal

 

[So]

Originally posted by: Colt45
A PIC is like $3, not $40.

I'd probably rig it with remote-control car servos somehow.. they're cheaper.

I PIC is like $3 if you buy them in huge lots (thousands) from a retailer, for a handfull, you'll pay much more.

 

[Colt45]

Originally posted by: So

Originally posted by: Colt45
A PIC is like $3, not $40.

I'd probably rig it with remote-control car servos somehow.. they're cheaper.

I PIC is like $3 if you buy them in huge lots (thousands) from a retailer, for a handfull, you'll pay much more.

ok, $5...7 or so

 

[dmurray14]

hmm...this could get interesting

I feel like there must be a more simple way than using a wireless modem....

and it would be pretty cool to figure something out with Wifi- but probaly even more expensive

 

[91TTZ]

Originally posted by: Colt45

I'd probably rig it with remote-control car servos somehow.. they're cheaper.
I guess servo is wrong word.. i thought RC cars had servo motor + reciever one piece?
must be seperate.

No, they're separate.

 

[dmurray14]

Originally posted by: harrkev
We have the technology... We can build it... But at what cost...

Wireless data transmitters and receivers are available, but at a price. Expect to spend at least $100 per unit on just that. For the radio portion, you will need to get a generic radio modem, and program a processor to decode the data. Here are some manufacturers, but not necessarily the cheapest ones:
http://www.data-linc.com/plantlinc/
http://www.radiodata.co.uk/Products/rdt-data.htm
http://www.elprotech.com/elpro/405.htm
http://www.intuicom.com/

Most sprinklers operate off of a solenoid. Power will be your big problem. It will take some battery juice to hold the solenoid open.

Expect to roll-your-own here. You will need per sprinker or zone:
(note that my prices are ball-park estimates)
1) Wireless receiver - $100
2) Large rechargable battery. Probaby a gell-cell would be the best - $20
3) Microprocessor to receive and decode the wireless data. A "Pic" or "Basic Stamp" should be OK - $40
4) Solar Cell, fairly large to recharge the battery - $40
5) Solenoid valve - $10 (you may already have these).
6) Some sort of plastic or metal housing to protect this stuff from the weather - $20.

So far, we are up to $220 per unit. So the grand total will be $6,600. This is assuming that you can find a radio receiver for $100. You will also need wire, perf-board, caps, resistors, etc.

Have fun!

By the way, $220 per unit is not a problem at all. We could probably do around $500/unit for just the receiving equipment. Does this open up the creative damper?

Dan