Mail Notifier
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SETEC_Astronomy
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Mail Notifier
For various reasons I want to make a circuit to detect when I have mail waiting in the mailbox. I've looked at several designs on the net but they all rely on monitoring the door of the mailbox, something I have a problem with regarding reliability. I'd like to make a mail present circuit that utilises a beam break sensor but that has lead me to a few issues, the first of which being power consumption. I want to build the circuit as efficient as possible while still being of reasonable complexity. What I've come up with so far is a 555 timer producing one high pulse every ten minutes which powers an LED. If mail is present the light is blocked which presents problem number 2. To deal with problem two I thought to use a missing pulse detector and tried to ignore the increased complexity and power consumption. So once every ten minutes if the beam is blocked my wireless transmitter is activated. To really keep power down I'm only turning on the transmitter for a short time (under 1 sec) and transmitting the data indicating the presence of mail. What happens on the receiver end is irrelevant in this case as power is not an issue inside the house and I've already figured out that part of the system. What I have to work with is caps, resistors, 555 timers, uCs and a transmitter with only three connections (power, ground and transmit). So my question is can anyone suggest a better, more efficient and reliable system? Thanks for any ideas you may have and I look forward to hearing them.
Start with one of these:
http://www.glolab.com/dp-001/dp-001.html
Set its sensitivity way low, and select an output "On" time to fire your transmitter.
It's a very versatile little motion detector. It could sit in the back of your mailbox, and an opening door, or falling envelopes would activate it for your predetermined time to turn on the transmitter. It will drive a load of 100 mA by itself. Consumes microamps in standby mode.
John
http://www.glolab.com/dp-001/dp-001.html
Set its sensitivity way low, and select an output "On" time to fire your transmitter.
It's a very versatile little motion detector. It could sit in the back of your mailbox, and an opening door, or falling envelopes would activate it for your predetermined time to turn on the transmitter. It will drive a load of 100 mA by itself. Consumes microamps in standby mode.
John
WA2RBA
As a word of caution. I was working on the same thing several years ago for my mother who had to walk about 100 feet to a mailbox on the street.
If you are in the US you may want to check with the postmaster general as at that time anything attacted to the mail box had to have his approval.
Also recently I was advised by the postoffice that the post office does not have to deliver mail to an unapproved mail box or one that looks offensive.
Ned
If you are in the US you may want to check with the postmaster general as at that time anything attacted to the mail box had to have his approval.
Also recently I was advised by the postoffice that the post office does not have to deliver mail to an unapproved mail box or one that looks offensive.
Ned
I did exactly what your wanting to do for a school project a couple years ago: http://pauljmac.com/projects/index.php/Mails_Here!
EDIT: Phpbb 2 does not like !s in a URL. Your gona have to coppy and paste it. The ! is the last character in the link.
I used a Photoresistor and and a POT on the input capture compare ports on a PIC. The POT made it easy to adjust sensitivity of the photoresistor.
The idea was a mail box is normally dark. When you open it up it allows light in, which triggers the CdS and wakes the PIC up and makes all the good things happen.
I threw around the idea of a breaking beam like you're talking about but as you said there are issues with power consumption there as well as complexity of the mail has to be put in a certain way to break the beam.
I think at one time I calculated I can get ~25 days off of a 9V bat. Which isnt good at all but this was my first project and I probably could have done a lot of things better.
EDIT: Phpbb 2 does not like !s in a URL. Your gona have to coppy and paste it. The ! is the last character in the link.
I used a Photoresistor and and a POT on the input capture compare ports on a PIC. The POT made it easy to adjust sensitivity of the photoresistor.
The idea was a mail box is normally dark. When you open it up it allows light in, which triggers the CdS and wakes the PIC up and makes all the good things happen.
I threw around the idea of a breaking beam like you're talking about but as you said there are issues with power consumption there as well as complexity of the mail has to be put in a certain way to break the beam.
I think at one time I calculated I can get ~25 days off of a 9V bat. Which isnt good at all but this was my first project and I probably could have done a lot of things better.
There is an easy work around for broken URLsChupa wrote:I did exactly what your wanting to do for a school project a couple years ago: http://pauljmac.com/projects/index.php/Mails_Here!
EDIT: Phpbb 2 does not like !s in a URL. Your gona have to coppy and paste it. The ! is the last character in the link.
when embedded in posts. Check out this comment.
That's a nice looking project Chupa! Well done!
SETEC- For simplicity, the PIR module and a transmitter is all you need.
The PIR consumes 38 microamps while watching for movement. At that rate, a standard alkaline will die from outdoor exposure before it runs down from usage.
I have a source for transmitter-receiver pairs for about $10, 200 yds range. PM if interested.
John
SETEC- For simplicity, the PIR module and a transmitter is all you need.
The PIR consumes 38 microamps while watching for movement. At that rate, a standard alkaline will die from outdoor exposure before it runs down from usage.
I have a source for transmitter-receiver pairs for about $10, 200 yds range. PM if interested.
John
WA2RBA
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Robert Reed
- Posts: 2277
- Joined: Wed Nov 24, 2004 1:01 am
- Location: ASHTABULA,OHIO
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Hi Robert-
These folks have a plethora of RXTX combinations! Something for everybody!
Specifically, this is the single channel, momentary (as long as the transmit button is depressed, the receiver relay is held closed), and 200 meters range-The TX and RX are solder-jumper selected to match digital codes.
http://cgi.ebay.com/1CH-Momentary-RF-Wi ... m153.l1262
Great folks to deal with also.
John
These folks have a plethora of RXTX combinations! Something for everybody!
Specifically, this is the single channel, momentary (as long as the transmit button is depressed, the receiver relay is held closed), and 200 meters range-The TX and RX are solder-jumper selected to match digital codes.
http://cgi.ebay.com/1CH-Momentary-RF-Wi ... m153.l1262
Great folks to deal with also.
John
WA2RBA
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