loboat

Possible... I used Eagle for the schematic representation of the circuit, but I didn't do any routing with it. If you want to, you have to do some modifications :)

Beautiful creation. I definitely want to build one now !

Yes, with an oscilloscope and a function generator :) (as I explained in the step 1, "How to use these devices").It's the only way

no, unless you change the circuit and the all project...

You can use any app with this hardware. I recommended the ones i found great for my purpose. Bluetooth oscilloscopes have the main advantage to be totally isolated from the input signal. There's no possible way that your phone can be damaged in case of trouble. But, they are more complicated to build : you will need prog skills in addition to electronics skills.

There is no relationship between the pin numbers of the lm324 and the pin numbers of the OP amps used in the eagle schematic. That's why ! :)Just make the circuit using the 4 OP amps of the lm324

Yes. You can check this specification by studying the lm7808's datasheet (you can find it with a quick google search btw)

Congratulations !! I hope this project will be usefull for you :)

You only need to connect the positive and the negative to the lm324. See the datasheet of this component to find the pins useful on it.I posted a picture of the lm324's datasheet in a previous comment if I remember well.

see step 2 for the total cost !

You only need to connect the positive and the negative to the lm324. See the datasheet of this component to find the pins useful on it.I posted a picture of the lm324's datasheet in a previous comment if I remember well.