The cheapest toy keyboard from ebay, Peng Zhan 168B

[phlogister]

Happy holidays!

I'm not an expert in circuit bending. This keyboard costs $7 with shipping when bought from America, and $5 with shipping when bought from Europe. I suspect the next one is produced by the same company and uses the exact same microcontroller, only has fewer keys, this one costs $1.65. The black keys don't play. When using it with Arduino (what i really bought it for), its possible to make the black keys to play like by putting a cardboard board below the keys, who has a patience of making it.

The sounds seem to be similar to a recorder, and the songs mostly played with a recorder or a bagpipe, seem to sound the best on it. The sounds seems to be triangulal wave, which is the most similar to sine. It seems that a frequency envelope was the easiest way to make sounds less monotonous. But at that it has no volume envelope, so the sounds end somewhat disruptly. It has no polyphony, the sound engine doesn't detect the release of the keys, so sounds played separately always have the same length, and it has no other effects.

This orange switch there is for switching to the mode where there is a song under every key, or rather they are only parts of the songs, some played with wrong speed, and there are the same songs under different keys. There are no other effects or modes.

The images below cannot be used for commercial purposes, by the photobucket license,



http://i1266.photobucket.com/albums/jj531/benshida/WJ/WJ012/1587846106_1521803253_zpse833b2aa.jpg

This is my video showing the keyboard, its sounds, the components inside, which are not many, and the modifications i made. Which is just soldering there two trimmers. What concerns circuit bending, then on this keyboard it doesn't make the keyboard anyhow worse, but is rather necessary to use that keyboard at all. Because as it originally comes, it is insanely loud and clearly overpowered, the frequency envelopes are not noticeable at all, and the sounds are more like just a monotonous beeps.

https://archive.org/details/pengja

The trimmer in series with the power supply enabled to starve the microcontroller of power. These were the sounds produced.

http://picosong.com/QS22

To give you some idea of how it sounds, spanish coffee, but low quality, it is quite difficult to hold headphones with microphone and keyboard in one hand, and play with another hand.

http://picosong.com/QUV5

Thank you, hope it was anyhow useful for anyone.

[phlogister]

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.

[phlogister]

To be more precise about the price, the price of that keyboard is $1.78 with shipping when shipping to America http://www.ebay.com/itm/1Pc-Popular-Mini-Plastic-Keyboard-Piano-Electronic-Kid-Toy-Musical-Instrument-/141807432001?hash=item210461b141:g:4EkAAOSwA4dWJEeO
, and $1.60 with shipping when shipping to Europe http://www.ebay.com/itm/1Pc-Popular-Mini-Piano-Plastic-Keyboard-Electronic-Kid-Toy-Instrument-Musical-/191815912021?hash=item2ca91e8a55:g:r1oAAOSwo0JWIKAz#shpCntId . The ebay listings may change, so when that happens, search ebay for "electronic toy keyboard" , and choose lowest first. There is likely no musical instrument cheaper anywhere, when bought as new.

More pictures.

[jamespoo]

mine came in the post today took 7days to get to new zealand

these things a neat to fiddle around with and bust out some basic song tunes

but would be amazing to be able to circuit bend these