PicAxe Projects > PicAxe 20M/X2 Servo Controller

Finished PicAxe-20M/X2 Servo Controller

Finished PicAxe-20M/X2 8 Servo Controller

PicAxe 20M 8 Servo Controller

PicAxe 20M 8 Servo Controller V.2 - download the Diptrace files here! V.2 is finished.


NOTE: This is a project that is in progress... proceed to build at your own risk. I decided to include the programming circuit since the resistors needed to be there anyway. So, a free bonus of a programmer!

Circuit used: The circuit is my fault and mine alone.

Parts List: PicAxe-20M/X, 20-Pin DIP socket, 1 10K resistors, 1 22K resistor, 9 3-pin headers, 1 8-pin header, and 1 2-pin header. Additonally, a LED and a 330 ohm resistor for the LED. Also needed is a power jack and a 5v wallwart. I might add the 5V regulator parts in a later version.

Construction Notes: If you look closely at the PCB layout, there are two jumper wires that isn't on the schematic, but it couldn't be avoided. I used my toner transfer method to make the PCB. I also added better markings for the silk screen (programming, servo headers, inputs, etc). See the PicAxe 20M programmer page for the construction of the programming adapter.

Programming: I will post some basic servo controller programs once I have completed the board.

Toner Transfer Note: the bottom of the board is NOT mirrored before printing (it automatically mirrors)! It seems like I have messed this up more than once. Just flip the text. The silk mask gets mirrored AND the text flipped. Also make sure you print it all in black to get the greatest density of toner.

April 16, 2011 - I managed to find time to populate the board. I haven't tested it yet, but will get to it shortly.

April 17, 2011 - Testing revealed a bit of a problem. I needed a 330 ohm resistor from the PicAxe chip output to the signal wire of the servo. Big oops... So, as printed, it does not work. I am working on V.2 as we speak. I am going hopefully going to get it etched this evening. We'll have to see how it goes.

April 19, 2011 - I got the V2 board etched and marked. I tinned the traces manually with solder. Sucked, but I haven't ordered my Tinnit yet. I will get it populated at sometime this week and then continue testing. I added the +5v regulator and the 330 ohm resistors that I was missing.

April 25, 2011 - I uploaded the new schematic and Diptrace files. You can download them at your own risk here. I still need to populate the board and test it. However, I did want to get the new files up.

May 3, 2011 - It is DONE!!! AND IT WORKS! There are a couple of things to pay attention to. First, the center pin of the power plug is negative. There are no protection diodes (READ: You can blow your chip if you are not careful!!!). If your wall wart's center is positive, you could blow the PicAxe chip. You can get my sample code here (save it as a .bas file). It moves the first three servos connected to Servo0, Servo1, and Servo2 moving from one end to the other each in turn. You could use the input pins to trigger servos to do seperate tasks... Use your imagination...

Bottom of board

Here is the first pass at the board. I should have run it through the laminator a couple of more times.

PicAxe-20M/X2 8 Servo Controller V.1 - Top Silk

Here is the top side of the board. Looking good so far. Only needed two jumpers. I may redo the board to include the 5V power regulator

V.1 board popluated, not tested

Here is the V.1 board popluated, I haven't tested it yet


Bottom of Board V2

Here is the bottom of the V2 board. I tinned the traces with solder. PITA, but I haven't ordered my Tinnit yet.

Top of Board V2

Here is the top of the V2 board. I might need to adjust some markings. Other than that, I think it turned out ok.

Populated V2 board

Here is the final test setup. Everything works as advertised! I am very pleased with the way it turned out.


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