cannot be found somewhere, and in short order. We have a Maytag dryer at o ur summer house, and just replaced the belt, rollers, idler and motor with new parts (made in Mexico and the USA) all for less than $100 installed (by me). It was made in 1971.
llons of water left behind (full load) that has to be dried. And more. But, they do work well, when they work.
I did go to those websites and find my part number, only to see them all ma rked "out of stock."
But then the problem solved itself, so I'm fine.
If I get another 20 years out of it, that's probably more than I have left anyway! Hee, hee.
But appliances controlled with expensive electronic boards, like modern ref rigerators, washers and dryers, scare me. Power fluctuations take them out so easily. I hate extended warranties but these may be necessary for some equipment. That mechanical timer could be replaced, with some effort for one that didn't quite fit maybe. Or I could put 8 toggle switches in a box and do it manually if I had to. Once a board goes I'm stuck.
I setup an Arduino (Uno) as the heart of a semi-automated controller for my BIL's extensive model railway layout.
The test track I have here is just a 3m straight length of (OO) track on a bit of timber with a small passing place in the middle section, joined to the main line with a couple of sets of points.
There are diodes in one track leg near the ends to kill the power to the loco if it was to overrun (but allowing it to reverse out).
There are 4 coded IR sensors on the track, two near the ends, two just outside the points.
Arduino ramps up the PWM, loco pulls away and accelerates (with inertia) to full speed till it passes the sensor past the distant points then decelerates (again with inertia) and then creeps to the furthest sensor then stops.
The points change (capacitor discharge via electronic bridge drivers) then the loco pulls away, round the bypass and to the other end.
Rinse / repeat.
The idea was to have some automated bits of track that ran stuff at the back of his main layout, just to keep something running while he was working on the layout or running other stuff himself.
The full project was going to be a main line with two sidings at each end.
The track would be broken up into at least 5 sections, the main run and the 4 sidings. All 5 could be driven independently (but as one) and each section 'sensed' for current draw to determine occupancy / transition.
3 locos (probably railcars / trams) could be placed on the track, two in any of the 4 'ends' and one on the main line.
On startup, the Arduino would test each section of track for occupancy (test current pulse), set the points to one of the empty sidings and drive any loco on the main line into an empty siding.
Now it would randomly select one of the two trains facing the empty siding at the remote end and set the live line to that siding. It would then slowly run out onto the main line (past a sensor), accelerate to full speed (user setable with a pot) to the remote sensor then slowing though the points and to the end on the empty siding. We could add a halt / station in the middle if we wanted.
Re evaluate and run again, either randomly or cycling though all three locos / units.. ;-)
During out initial trials we learned we would probably have to select a small subset of similar spec models from his extensive collection to ensure the performance of each loco was similar.
Because he has quite a collection, he really didn't want to go digital, hence all the intelligence had to be in the track.
We might also need to use the Arduino to drive an independent PWM controller with feedback, to allow better control.
I have an Arduino Mega running the 3D printer I built a few years back. ;-)
I have a Raspberry Pi3B running Open Media Vault (NAS) on a 3TB USB drive and another running TVHeadend with a couple of HD TV tuners.
This one is just a solenoid hitting one chime (Ding) and then dropping back to the other (dong) when the button is released.
Ok ...
Ok, so when I first hooked it up it will pull the bell in 'Ding' and hold it in till the charging current dropped back enough to allow the solenoid to release (which might be slow so we might not ever hear a clear 'dong')?
Ok. I follow that.
What if the buzzer was (across your diode) in series ... with another reversed diode and resistor in parallel?
eg, charging current passes though original diode / buzzer, combo, through the resistor and into the cap. Then when the button is pressed the cap charge passes through the second diode, though the buzzer and to the switch (and back to the -Ve of the cap etc)?
What sort of leakage do these caps have Chris?
Understood, or I could pre-charge it? ;-)
plus another diode and suitable resistor ...
Well it is a solenoid so it might have a bit.
I was hoping to go for a electro mechanical buzzer so that it actually resonated the door frame a bit, rather than just be a beep in parallel with the existing doorbell.
Not if I get the charging resistor right?
Basically, I don't think I need a big cap, just one big enough to allow the buzzer to sound briefly, just to provide feedback to anyone outside that the button did work (and ideally I wouldn't want it to run much longer in case they did hold their finger on the button).
I'll have to rig something up and see how it goes (and it's easier to find 6V buzzers). ;-)
Cool, I've ordered the same thing (and in white) from Amazon UK. ;-)
Agreed, if at all possible and as long as it works. ;-)
Do you think I'll need to limit the voltage across the buzzer (2 (/3) diodes in series in parallel with the buzzer?) and that the existing bell draws at least 25mA?
"* Minimum Input Voltage: 1.3V* Maximum Input Voltage: 2V* Current Consumption: 25mA* Nominal Output @ 30cm: 75dB* Output Frequency:
I had considered suggesting such an arrangement, but then I thought that the simpler option would probably be good enough.
Here is a datasheet. Tens of microamperes or less. I didn't know but they come in voltage ratings above 5.5V so you would only need one capacitor:
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True. That's the main advantage I can think of for putting a charging resistor. There might be an argument for using a zener diode rather than a rectifier diode in parallel with the charging resistor, as I don't know whether breakdown might be destructive for a diode not intended as a zener.
Yes, a smaller capacitor would do if you have a suitable one on hand.
I think you should try it and please report back how it goes.
That would depend very much on how long your delivery individual holds down the button. But a couple-of-ohms, 1-watt resistor, or so, in parallel to the buzzer should give all the protection you need. One watt is crazy-overkill, but cheap enough.
If it's anything like the Hermes delivery at 8 last night, too long (or two many times). ;-(
So if using a resistor in that role I really need to match the resistance to the resistance of the solenoid to give me the right voltage drop over the buzzer (potential divider), hoping the worst case is not too much voltage across the buzzer and when the batteries are on the way out, enough for the buzzer bit to still work?
If I had a suitably low value (ww?) pot, I could put that across the buzzer then tune it for the best sound with the Ni-Mh cells (then replace it with a fixed resistor etc)?
Why wouldn't a 'voltage' regulated solution be better, given how little voltage we have spare to play with and the fact that the voltage will change with time?
It looks like you can get 1.5V zeners so as long as they can manage the current though the existing bell and the back EMF etc, wouldn't that be the more subtle way of managing it all?
I just stuck my DMM across the contacts on the bell push (at the bell itself) and with a 6V battery supply I measure ~750mA (dropping to ~730 after a few seconds). That puts the bell solenoid resistance at around 8 ohms (plus what I would get via the cabling etc).
If the buzzer draws 25mA at 1.5V then the buzzers resistance is around
60 ohms (I know that isn't ever going to be a pure resistor, unlike the saturated solenoid) so adding that in series with the bell is going to give me around 70 ohms and a maximum current of ~85mA.
That's roughly 5V across the buzzer and 1V across the bell.
Putting a 2 ohm resistor in parallel with the buzzer will give me just over 10 ohms in total, so back up to around 600+mA, and so 1.2V across the buzzer and 4.8V across the bell (and I know it works with 4.8V's worth of rechargeables. ;-)
However, aren't we wasting energy in a resistor system, rather than clamping voltage using a (say) a zener or is it the same thing?
Are these the sorts of things they have in these clever capacitive based vehicle jump starting units?
Understood.
You should see from elsewhere I'm going to try the low voltage series buzzer first and yes, of course I'll report back as I can't be the only one in this position who might appreciate a 'simple' solution? ;-)
The resistor is on play only when the button is being pushed. So the amount of energy 'wasted' is negligible. The buzzer is rated up to two (2) volts. Which suggests that a 1.5 ohm resistor will accommodate voltage swings from the battery and still protect the buzzer. Resistors are far less complicated (and thereby more reliable) than a diode, more so if that diode is a zener. The idea is to pass enough current to trip the bell solenoid, yet not damage the buzzer. I am not so sure batteries, buttons, buzzers and bells understand the concept of "subtle" on the one hand. They may understand "elegant" on the other hand. On the gripping hand, they certainly understand "simple". I am trying to limit the number of parts involved with the least complicated, most efficient solution that uses what is already in place, and also does not involve brain-damage.
There you go Petey! See, it's not so hard to be helpful. Just don't inject to much of your inner thoughts when you reply. Give only pertinent information like in this example. :)
efrigerators, washers and dryers, scare me. Power fluctuations take them ou t so easily. I hate extended warranties but these may be necessary for some equipment. That mechanical timer could be replaced, with some effort for o ne that didn't quite fit maybe. Or I could put 8 toggle switches in a box a nd do it manually if I had to. Once a board goes I'm stuck.
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