This is my second Picaxe project . It is a simple servo tester or servo cycler built using an 08M . It has 3 modes of operation . In mode 1 each servo is controlled by its own pot . In mode 2 both servos are centered with a 1.5 millisecond pulse . In mode 3 both servos are cycled with the left pot setting the low end point and the right pot setting the high end point . The modes are cycled using a normally open switch . I had to use the pulseout command instead of the servo and servopos commands to avoid jitter .
I used an enclosure from an old rc toy airplane charger for the case . It was a tight fit for the 4 AA battery box , 2 pots , circuit board etc. The circuit board was made by laser printing onto a label backing sheet and transferring by iron to the pcb . Ferric chloride was used for etching . This was the first time I tried the laser printer method and the results were ok but not great .
I know you can buy a single channel version of this for a few dollars but I like to make my own stuff . It's really handy for setting up servos without doing any programming . I have included the basic program and schematic for anyone who is interested .
I have built myself one few months ago. Mine is very simple comparing to yours, it just controls 2 servos with 2 pots. And it is very bulky as I’ve used my favorite enclosure - lunch box I believe this device is a MUST HAVE for a robot hobbyist, and as you have said, preferrably DIY. Thanks a lot for posting! Ah, here is mine:
Thanks . I included the schematic as an attachment along with the code . I have edited the post to include the image in the main body . I’m new here so I’m still not sure where to put things .
What processor did you use or did you use a 555 timer . I like food containers as enclosures also . Here is a picture of my FTDI breakout board with a Picaxe programming jack .
I’m using a Stamp board to compile Servopot4.bas and Im getting th following error: ‘serfreq’ command not supported in this mode, does it mean I have to get a Picaxe 08M in order to run Servopot4.bas?
I am not familer with your Stamp board . Is it the original Parallax Basic Stamp , also called the Stamp 1 ? The program will not run on a Parallax Stamp . It will run on an Picaxe 08M without change . I haven’t tried it yet on an 08M2 . I have some ordered and will post any code updates as soon as I can .
I have experimented with something similar, but with the pots placed on a joystick: PIC-AIM. I struggled with it for a month with no success. Servo jitter was my enemy. The funny thing is that I have collected this page of yours before I started that experiment. It looks as though the answer to my problem has been in “My Collection” all along. I´ve taken a look at your code and your pulseout approach looks promising. I can´t wait to adapt it to my gizmo.
For some reason I remembered this project of yours today…
I would delete the first ‘pause 50’ and change the second one to ‘pause 25’ but I don’t think that’s your problem . Is the circuit built on a breadboard ? Have you tried adding a 100 or 220 uF cap where the power supply comes onto the board ? Measure voltages while its running . Try measuring voltage from where ground enters the board to the ground pin on the picaxe and the ground pins of the servos in case you have a bad connection . Do this for the positive voltage also .If the connections are good the voltage reading should be be close to zero . While it’s running , push on the connections . Whenever I have any kind of erratic behaviour , I always look for bad connections . You can also try the following code that does’t read the pots to try and isolate the problem . It just sets the servos to center position .
I believe this device is a MUST HAVE for a robot hobbyist, and as you have said, preferrably DIY. Thanks a lot for posting! Ah, here is mine:
