Show HN: Mantel-top computerized musical chimes with MicroPython on an ESP-32(github.com)
github.com
Show HN: Mantel-top computerized musical chimes with MicroPython on an ESP-32
https://github.com/keredson/chimes/blob/main/README.md
17 comments
Beautiful project! I love how it turned out and I'm impressed by the homemade solenoids.
I don't quite understand how the strikers work. Is there something magnetic attached to the top of the wood dowel?
I don't quite understand how the strikers work. Is there something magnetic attached to the top of the wood dowel?
The electromagnets are used as a solenoid, it seems.
So, the electromagnet ‘pulls’ the piece of steel into its inner cavity.
The wooden stick and bead seems to be arranged and mounted in a way that gravity will ‘pull’ the piece of steel away from the solenoid.
I think the solenoids are only strong enough to ‘swing’ the stick and bead toward the tube, but not hold it in place for a sustained period.
[update]
Totally wrong. Seems to be the opposite. The solenoid sucks in the piece of steel, moving the stick and bead away from the tube, but normally, at rest, the bead rests against the tube, because of the hinge and gravity.
So, the electromagnet ‘pulls’ the piece of steel into its inner cavity.
The wooden stick and bead seems to be arranged and mounted in a way that gravity will ‘pull’ the piece of steel away from the solenoid.
I think the solenoids are only strong enough to ‘swing’ the stick and bead toward the tube, but not hold it in place for a sustained period.
[update]
Totally wrong. Seems to be the opposite. The solenoid sucks in the piece of steel, moving the stick and bead away from the tube, but normally, at rest, the bead rests against the tube, because of the hinge and gravity.
On the dowel there are 5 steel nuts which are pulled towards the electromagnet. Gravity makes them return, but TBH it's not reliable enough. I'm working on a new version with small return springs and a wider swing for the striker.
The electromagnet is pulsed to control how hard to strike.
The electromagnet is pulsed to control how hard to strike.
Really impressive work!
I am really interested in what you are able to come up with.
I remember taking apart old telephones with bell ringing mechanisms.
That might be a source of further design inspiration for you.
Maybe ballpoint pen springs?
I purchased a child’s xylophone to try something similar with, but the cost of the solenoids was a dealbreaker for me at the time ($6+ per solenoid on eBay).
I am really interested in what you are able to come up with.
I remember taking apart old telephones with bell ringing mechanisms.
That might be a source of further design inspiration for you.
Maybe ballpoint pen springs?
I purchased a child’s xylophone to try something similar with, but the cost of the solenoids was a dealbreaker for me at the time ($6+ per solenoid on eBay).
Even more crazy were these "iron core for electromagnets" https://www.amazon.com/Soft-Ideal-making-electromagnets-inch..., 6" for $17.
Give me a break. Soft steel is >99% iron and I bought 4' for <1/2 that price from HD. Rip-off.
Give me a break. Soft steel is >99% iron and I bought 4' for <1/2 that price from HD. Rip-off.
Hah, yeah, I think I saw them on Amazon for like $20. That seemed nuts; why I decided to roll my own.
Did you consider using servos vs electromagnets? Curious if small servos couldn’t accomplish the same goal.
That is a good idea. Those 9g mini servos are only $2 each, so that is much more affordable than the ‘retail’ solenoids.
If you are willing to wait on them, you can get 5 packs of 9g servos for $2 including shipping from China.
I am interested in that url, please.
I’m not seeing them in stock with the sellers I usually buy from, but here is a 4 pack for $4.39 including shipping from China ($2.09 from US, but not free shipping):
https://m.aliexpress.com/item/4000066002225.html
https://m.aliexpress.com/item/4000066002225.html
I hadn't even thought of using small servos. Possibly that would have been a lot simpler! I went though a bunch of prototype EMs testing to get a working combo of voltage, windings, core size, etc. (Blew more than a few driver circuits too...)
I was wondering this too.
Thank you!
There's a little plastic hinge that goes on the end of the dowel / slots into the hanger. I don't have a picture, but the file is here: https://github.com/keredson/chimes/blob/main/striker_hinge.s...
There's a little plastic hinge that goes on the end of the dowel / slots into the hanger. I don't have a picture, but the file is here: https://github.com/keredson/chimes/blob/main/striker_hinge.s...
Nice hack.
Two tangential complaints.
First, it sounds to me like the ninth note is off - it's lower than it should be.
Second, that page ate a huge chunk of my monthly mobile data allocation.
Twice. Because I made the mistake of clicking the image for the video, instead of opening it in a new tab. The page reloaded in full on the back button.
Two tangential complaints.
First, it sounds to me like the ninth note is off - it's lower than it should be.
Second, that page ate a huge chunk of my monthly mobile data allocation.
Twice. Because I made the mistake of clicking the image for the video, instead of opening it in a new tab. The page reloaded in full on the back button.
Ouch, I'm sorry. When I get home tonight I'll check to see if GitHub supports loading=lazy.
I can't believe you soldered directly to the ESP though! Seeing that gave me anxiety, haha.