So, I figured for my first foray into Arduino tech, I would set up a notifier for my mailbox. Like the title says, However, there's a twist.
My box is located in a huge bank of mailboxes. It's set up like a typical post office box: it's open on the back end where mail is inserted, and has a key lock on the "customer" end. It looks something like this:
Yes, I whipped that together in paint in about 5 minutes.
Now, as far as I know, there is no always-on power available save for an always-on fluorescent light in the open-end. (There may be an outlet, I'd have to ask, but I bet they wouldn't like my power cable draping down half a bank of boxes).
I was hoping that I could find something extremely low powered with Wi-Fi (there is a wireless network available), and something to detect a letter put in the box, like a beam-break sensor or IR ranging sensor. The box itself is made of what looks like aluminum, that's somewhat reflective.
The "Draping power cable" concern is for the convenience of putting mail into the boxes below mine, not for the "OMG small chip with a single LED IT'S A BOMB" concerns. I would of course notify my mail carrier (In this case, a University office that sits in the same place as the mail room, and has complete control of it) that I intended on putting a sensor in that notified me when my mail had arrived; nothing more.
How often are you expecting mail? You could have a simple to remove lipo battery or something, buy two and then swap them over every week or so perhaps.
Wifi is a bit of a power hog so could you have a low power wireless link to another unit that would connect to the wifi network.
mowcius:
How often are you expecting mail? You could have a simple to remove lipo battery or something, buy two and then swap them over every week or so perhaps.
Wifi is a bit of a power hog so could you have a low power wireless link to another unit that would connect to the wifi network.
I'm not expecting mail too often, so It's possible that I could just throw a battery in when I place an order for something. As for the low power link, I'm not even remotely in the same building as the mailboxes. I'm located in a "neighboring" building almost 2 blocks away, So Low-power linking to a wall-warted wi-fi module is Probably out.
So Low-power linking to a wall-warted wi-fi module is Probably out.
Well as the only data you really need to send is a 1 or a 0 (mail or no new mail) then you could use a very very simple RF link which could be low power.
One of the issues is with the metal boxes - RF doesn't like metal being in the way too much.
So - how long might you need this thing on standby? You could get a cheap mobile phone to ring you when there is mail (if you can get mobile phone signal in the box).
If you didn't answer the call then it wouldn't cost you anything each time you got mail.
Now, as far as I know, there is no always-on power available save for an always-on fluorescent light in the open-end.
So is there a light in each box? I presume you can't hack into the power of this though else you would have said so.
mowcius:
Well as the only data you really need to send is a 1 or a 0 (mail or no new mail) then you could use a very very simple RF link which could be low power.
One of the issues is with the metal boxes - RF doesn't like metal being in the way too much.
Let me rephrase that; I have no way to put a low-power receiver within range of the mailbox to receive the "Beam Interrupted: Mail arrived" signal, unless the low-power receiver has a range of half a mile, in which case, it probably isn't low power.
mowcius:
So - how long might you need this thing on standby? You could get a cheap mobile phone to ring you when there is mail (if you can get mobile phone signal in the box).
If you didn't answer the call then it wouldn't cost you anything each time you got mail.
I would hope for a week on standby, possibly even tweeting a message when the battery power gets low (But that's a coding issue). A cell phone is probably out, because I already pay enough per month for my mobile phone, and I don't need another monthly charge for something I'd be running for a week or two out of every month.
mowcius:
So is there a light in each box? I presume you can't hack into the power of this though else you would have said so.
No, The light is in the room behind the open end, where the mail is delivered from. I only mentioned it because it's a fairly bright light and seems to be always-on, so I figured it could provide a solar recharge for a battery or something, but seeing as it's a fluorescent light, probably not.
A cell phone is probably out, because I already pay enough per month for my mobile phone, and I don't need another monthly charge for something I'd be running for a week or two out of every month.
Well like I said, if you don't answer the calls from your mail box mobile then it won't be costing you any more than the phone itself (which you can probably get one for free).
Interfacing with the phone could be tricky though depending on what type of phone it might be.
Let me rephrase that; I have no way to put a low-power receiver within range of the mailbox to receive the "Beam Interrupted: Mail arrived" signal, unless the low-power receiver has a range of half a mile, in which case, it probably isn't low power.
Well, you'd be surprised of the range you can get out of low power devices, think of these battery powered radios you can get, you can get some that will last a week with occasional use and they will do >10 miles.
I would recommend this as an option (hacking one of these) but I'm pretty sure using them for data transfer is not allowed. I suppose if you simply send some audio pulses every so often, that aint exactly data transfer.