After a delay due to a temporary health issue I can now post something more meaningful.
First, a sample of the present state of my church bell (or rather clock) project on a breadboard; in this test set-up, I let the tower clock ring the hours as well as the half hours in between, but to avoid long waits between the first few hours strikes in the test I programmed a fixed pause between strike sequences instead of starting the strikes at fixed intervals. The video contains the half-hour strike (which is identical to the one-o-clock strike) and the strikes of 7 and 8. The difference in sound volume between the half-hour strike and the others is due to editing and will be remedied later. The set-up can be fit nicely on a fairly standard small breadboard of about 5×8cm.
The set-up on the breadboard consists, from left to right in the video, of
[1] An Arduino Nano clone for controlling
[2] A DFPlayer Mini MP3 player with a 256MB microSD card containing the sounds, connected to
[3] A speaker with decoupling capacitor.
Arduino, as per
the Arduino website, "is an open-source electronics platform based on easy-to-use hardware and software. It's intended for anyone making interactive projects."
The Arduino Nano is a small board that fits nicely on a breadboard; it provides various input and output methods and there is a huge number of extension modules. Its popularity means that clones, using a functionally equivalent communication chip (albeit with a different driver), are mass available for a few euros from sites like AliExpress or Banggood. When connected to a computer (from which it can be programmed) it can use the power provided by the USB connection; when operating stand-alone it needs either a 5V regulated power supply or an unregulated power supply of a somewhat higher voltage (where the acceptable voltage range varies between suppliers, probably due to the use of different voltage regulators). The programming language is quite comparable to C++.
You can find various descriptions of the use of this or similar boards for model railroad projects on this and other forums. Before my ongoing tower clock project I used these boards for controlling the lights in different rooms of toy houses according to time of day, with commands like
lightswitch(kitchen, on, "sasu", "17:30")
which switches on the lamp in the kitchen on 17:30 saturdays and sundays
[the quotation marks can be avoided for the time points by writing them as, e.g. 0030, 1730, etc. and treating them as integers, but that solution feels worse than the problem of having to use quotes; for the day abbreviations the only "solution" I can think of is to declare all possible combinations (1 for all seven days, 6+5+4+3+2+1 for 2 days, 5+4+3+2+1 + 4+3+2+1 + 3+2+1 +2+1 for 3 days, etc.) which would be using a sledgehammer to crack a nut].
Not listed above, but visible in the video and necessary for voltage levelling are two 1k resistors in the communication lines between Arduino (controller, 5V signal) and DFPlayer (controlled, 3.3V input).
The DFPlayer Mini MP3 player, as found on AliExpress et al., is a small, breadboard-friendly board that can play MP3 files from a microSD card. It can be controlled via serial communication, or manually with an arrangement of buttons. Power supply voltage is 5V (external or, like in my set-up, from the 5V pin of the Arduino). I came across it via
a post on the Particle forum. The decoupling capacitor between DFplayer and speaker was suggested by the starter of that thread. In the video above the speaker is an 8 Ohm 0.25W speaker from a long gone computer case. With the right casing (or even with the film box in the video), this produces enough sound for model purposes.
Jeroen
Edited by user 09 January 2025 16:43:38(UTC)
| Reason: Update
