A crummy little servo tester and other minutia

The little servo tester
Well, I needed a way to test all of these servos I got from EBay and I decided to spend a little time making a quick and dirty little board for doing that. It uses a PIC12F683 and has a linear pot attached to it. Simple.

Crummy servo tester

Crummy servo tester

Viscometer Board and stuff
I’ve been working on the software for the viscometer. Every function appears to work, at least based on the rudimentary prototype I have currently running. I am working on a scripting system for this device. I could make it just a basic viscometer but, as anyone that knows me, I simply can’t do. Here’s a pic of the working board.
The prototype viscometer board

The prototype viscometer board

An EEPROM file system
After thinking about how to store files appropriately and trying to have a file system that can work easily with 1024B of space, I started coming up with ways of defining a reasonable file system. Here it is.

  • First 2 bytes are settings, things like block size, filename size and special behaviors like for EEPROMS that can only be written to with blocks.also defined is the address size 8b, 16b or 32b
  • Each file in the FAT consists of a name of either 2,4 or 8 bytes. this is determined by the setting.
  • Following the name is one byte detailing the flags such as read-only, archive, and whether it’s open or not.
  • After the filename and attribute byte, are the addresses. These addresses can be 8, 16 or 32 bits, however, an 8 byte address can address something larger, say 2k rather than 256B if you set the block size appropriately. This of course lowers the efficiency of storage space but allows for some growth in the file. The file can have any number of addresses in order to remove time wasted moving stuff around.

Anyways, that’s what I’ve been working on as of late. Fun!

  1. paul
    December 23rd, 2009 at 09:06
    Reply | Quote | #1

    great page how about the circuit for the first little servo tester?

    regards paul

  2. smackaay
    February 8th, 2010 at 00:58
    Reply | Quote | #2

    Sorry about the late reply. Ok, I’ll draw it up as nice as I can and post it shortly.

  3. Victor C.
    September 24th, 2010 at 19:35
    Reply | Quote | #3

    Hi Steve,

    I am working on a little project, and I need to use a servo without a Tx/Rx, and your circuit and program could be just what I have been looking for. Would you mind sharing the schematic and program? I will more than happy to pay you some money if you want.



  4. Henrik
    March 1st, 2011 at 15:38
    Reply | Quote | #4


    I would be very happy if you could share the *.hex file for the pic12f683.

    Thanks in advance!

  5. smackaay
    March 2nd, 2011 at 17:42
    Reply | Quote | #5

    I would, however, I don’t have it anymore. 🙁 I may build a 555 timer variant since I’ve gotten so many requests.

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