I now also received the $1.65 (with shipping) electronic toy keyboard. It took two months for it to arrive from china. So i took some pictures with my not so good web camera. It was packed in a thin plastic bag like a one used for candies, this doesn't protect the keyboard anyway, so all the impact has to be taken by its case, made of very thin plastic as well. It came in too big for it plastic envelope, which had some bubble plastic inside. As a description it was written "piano".
No name of the manufacturer was written anywhere, but from the very similar artwork, very similar sounds and the same demo songs, it can be decided that it was made by Peng Zhan, and it had a number on it, so i name it Peng Zhan 517-27.
It was insanely loud, so i again had to solder the same 40k trimmers on it, as to the previous one, in series with the speaker and in series with the power supply. Without these it is useless, if you are going to buy one, consider that this is what you have to do, just to be able to use it.
I were able to make the sound normal with these two trimmers, but i were not able to get any circuit bent effects as with Peng Zhan 168B. It looks like much smaller trimmers are necessary to even get the sweet spot with that microcontroller.
The distance between keys is 13 mm, which is less than 14 mm on midget keys. This makes it somewhat more difficult to play, yet it is possible to play as you can hear here
http://picosong.com/hBnr . I'm sorry for the microphone always rubbing against the keyboard, i had to keep it at a distance. In short, sorry for the awesome quality, but it's just to give you some idea of how it sounds. These are all the demo songs of this keyboard
http://picosong.com/hBFH . The plastic domes are smaller than on Peng Zhan 168B, an thus the keys move less, yet they need some pressure to be switched, which makes playing somewhat more normal. The switch between playing and demo songs is backwards from the one on Peng Zhan 168B.
There are 8 keys that play, the black keys don't play, and don't even move. As you see on the images referred to in the previous post, it had scale numbers on it. But the most strangely, these scale numbers were completely wrong. And also completely unnecessary, as different from Peng Zhan 168B, it has a normal scale, the same as on an ordinary keyboard. But it appeared that the scale numbers came easily off with an eraser.
Before you open it, remember to first remove the cover of the playing mode switch, it can just be lifted up. Because otherwise it may jump off when you open it, and you may lose it. To open it, unscrew the four screws and carefully lift the upper half vertically. It is fixed only by pins that go into the holes in the lower half of the case.
Arduino nano can be put into the keyboard as shown. Fix it with a mounting tape or such. A hole large enough has to be made into the case, so that usb can be connected. A small round 9 volt battery (l1022) can be be used for arduino. I don't know whether it has a capacity large enough, all i know is that its diameter is less than on aa batteries, so it goes into the battery holder, these are also cheap. It should also not be very difficult to connect several in parallel. In spite that it has only 8 keys, it can be used for a first attempt to make a synthesizer with arduino, with some real keys and a speaker. Connect the speaker directly to the arduino output. Remember to put a 150 ohm resistor in series with the speaker, as connecting the speaker directly to the arduino output causes too much current that may damage the arduino output. It works that way, and should be quite loud.
Hope it was useful for someone for some purpose.
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Topic: The cheapest toy keyboard from ebay, Peng Zhan 168B (Read 6722 times)