Make a Solenoid - Mikes Inventions 

You really do want the only ferrous metal in the solenoid to be the actuator itself. If you use a metal tube as a winding base it will also magnetize and the two will be more attracted to each other than to the coil.

Hey there! Yes, you always wind the same direction, because if you switch directions, the fields will cancel out. It doesn't matter that the wire goes back and forth along the core. The right-hand rule determines the direction of the field. Thanks for watching!

@@MikesInventions Thanks, the video is great, my eyes not. Thanks again.

​@@MikesInventionsfalse - the windings should not go in opposite directions. That is to say, winding angular direction as well as linear direction along the length of the air core is crucial.

V = I * R 12v = ? * R ? depend on your current source capacity. If you have 2 Amp of sources, then: 12v = 2A * R R = 6ohm Read AWG's table. Look at the highest Resistivity, usually Ohm per km. Example: if there is 1 ohm per meter, you would take 6 meters of wire. Then make a coil from it. Finish.

Hey Joseph! The current is limited by the resistance of the wire. That's why there are so many turns. It takes a lot of wire to get the resistance up to a level where the amps remain low enough to not heat everything up. Also why low voltages are good for DC solenoids.

@@MikesInventions Okay. Thanks for answering my question. I actually took a two year course in electronics but for the life of me I couldn't remember what limited the current.

Hey! If you use bigger wire, the resistance drops, and so current will go up, creating a larger magnetic field. Current and number of turns determine the strength of the magnet. Thanks for watching! Make sure you use enough resistance (wire) so you don’t overload your power supply. Current goes up quickly with larger wires because the resistance drops off fast.

@@MikesInventions thanks

Hey Arun! All I know is that it was 28ga wire. (Still have some on a spool behind the monitor) I have no idea how many turns this was. It was just a fun build as an example for Alex really.

No. It needs to be soft iron. If you put in a magnet, your solenoid will only work in one current direction.

Hey Luke. I can’t remember what we sized it for. When you design a solenoid, you need to calculate the resistance if the wire then use ohms law to make sure you don’t overload it with the voltage you plan to use.

We've had beans, tomatoes, peppers, and herbs! The corn never grew well because of the shade from the trees. There are potatoes going there now. I stunted my garden by using such small beds for fruiting plants. I'm going to redo it for next year to include more dirt so that the plants have more room to grow, but the boxes are still intact and look great! Thanks for watching these videos!