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| Thread ID: 150222 | 2021-10-27 01:44:00 | WiFi from the mailbox - continued | Tony (4941) | Press F1 |
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| 1481605 | 2021-10-27 01:44:00 | This is a continuation of this thread: pressf1.pcworld.co.nz which has been closed for some reason - possibly lack of posts. Anyway, I've been working away, lockdown and weather permitting, and have it at the stage where all the mechanics and the electronics are working separately, but I'm having problems with the interface. It is supposed to be activated by a microswitch, but I can't get that to work satisfactorily. The problem is that the switch needs more force to actuate it than I am able to apply. I'm constrained by the dimensions of the letterbox, which won't allow me to extend the actuator arm very far, and I can't just add weight because it stops the rotating plate working with small weights on it. It will work with a magazine or a decent letter, but anything lighter just won't make it work. I decided to try something else, and found this photo interrupter (www.jaycar.co.nz) from Jaycar. 11175 I now have to make this work. As you will all have realized, my electrical knowledge is limited, to say the least. If I read the diagram correctly, if I supply power to K and A, and a lamp to C and E, the lamp should light until the current is interrupted by putting something into the gap. That's not happening, and I don't know why. Any suggestions? |
Tony (4941) | ||
| 1481606 | 2021-10-27 03:39:00 | Thinking about it some more, I realize my assumptions are totally wrong about the wiring of the interrupter, but I'm still not sure what I should be doing. | Tony (4941) | ||
| 1481607 | 2021-10-27 17:59:00 | The transistor side of the interrupter can't drive anything on its own; if you power one side of your lamp (LED?), then wire the other side to a resistor (depends what the lamp is), then through the interrupter at C, with E tied to the negative side of your supply, then when the LED side of the interrupter is active (use a series resistor to avoid blowing up the LED!), then the lamp should light up. | MushHead (10626) | ||
| 1481608 | 2021-10-27 19:58:00 | Thanks for that. It looks like it might me back to the drawing board, as the combination of my iffy soldering skills and the need to have something that is sturdy and weatherproof enough to live in my mailbox means this approach is probably a non-starter. | Tony (4941) | ||
| 1481609 | 2021-10-30 05:06:00 | What about putting a flap on the opening of the letterbox, and arming the flap? Flap closed, switch closed, system is off / standby (using no current), flap pushed open just a few mm and the switch is released to open and the circuit triggers. Set it up so you need to push the flap back down from within the letterbox to reset it back to the off/standby position, or atttach a small weight to the flap to have it self close / self reset if you wish. Edit: This might also solve the issue of stuff only shoved part way into the letterbox failing to trigger a system relying on the weight of the letter. |
Paul.Cov (425) | ||
| 1481610 | 2021-10-30 07:45:00 | What about putting a flap on the opening of the letterbox, and arming the flap? Flap closed, switch closed, system is off / standby (using no current), flap pushed open just a few mm and the switch is released to open and the circuit triggers. Set it up so you need to push the flap back down from within the letterbox to reset it back to the off/standby position, or atttach a small weight to the flap to have it self close / self reset if you wish. Edit: This might also solve the issue of stuff only shoved part way into the letterbox failing to trigger a system relying on the weight of the letter. Thanks for those suggestions. I've sort of been round that loop, and the issues are around the fact that the flap needs to be right on the balance point where it will move with just a single sheet of paper, and when it does that, it just doesn't generate enough force to trigger the Jaycar microswitch that I have. I have very light elastic attached to return it the starting position, and that also won't generate the required force. If I make the plate heavier to make it work on the downswing, I can't get the elastic to bring it back up. Its a real catch-22. I've been googling "zero force microswitch", and got a few hits, so I'll be making some phone calls on Monday. I've a horrible feeling they might want me to buy 100 (or 1000!) but I live in hope. |
Tony (4941) | ||
| 1481611 | 2021-11-01 07:14:00 | Ahh, well your plans for optical makes sense then. I wonder if an old mouse could be gutted for some of the parts... switch, LED light source and censor. I've had birds try to nest in my letterbox, plus ants and wasps, there's potential for some false alarms. Rain might also be an issue. I've had some posties that leave half the letter sticking out to catch the rain, with the wet envelope then acting as a wick to draw the water into the letterbox |
Paul.Cov (425) | ||
| 1481612 | 2021-11-01 07:30:00 | Dont know if this is of any help -- Do a google search for "letterbox notifier" Theres a couple of prebuilt ( including one fron Jarcar). The one from Jarcar lists all the components to make it yourself. Jarcar -- www.jaycar.co.nz |
wainuitech (129) | ||
| 1481613 | 2021-11-01 07:40:00 | Dont know if this is of any help -- Do a google search for "letterbox notifier" Theres a couple of prebuilt ( including one fron Jarcar). The one from Jarcar lists all the components to make it yourself. Jarcar -- www.jaycar.co.nz It's the Jaycar one I'm trying to build. That's not actually prebuilt - it's a set of instructions and a parts list. The microswitch I am having a problem with is in the foreground of the photo. |
Tony (4941) | ||
| 1481614 | 2021-11-01 07:54:00 | Ahh, well your plans for optical makes sense then. I wonder if an old mouse could be gutted for some of the parts... switch, LED light source and censor. I've had birds try to nest in my letterbox, plus ants and wasps, there's potential for some false alarms. Rain might also be an issue. I've had some posties that leave half the letter sticking out to catch the rain, with the wet envelope then acting as a wick to draw the water into the letterbox Yes, weather could be a bit of an issue. Once I actually get to install the whole thing I will be weatherproofing it as much as possible. That said, in fact my mailbox does keep pretty dry. |
Tony (4941) | ||
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