SAGAR Update, New Motor Controller and Motors

Posted in Projects by Bill
7 Aug 2010
SAGAR Update, New Motor Controller and Motors

Hey Guys,

It’s been a while since I posted an update on SAGAR, but here’s the latest.

I wanted her to go faster. My original motors would only do about 1.2 m/s tops. Well, with a little help from a friend, I found new motors that would bring up the top speed to well over 3 m/s. However, they require more current to reach that speed, more then my original controller could handle. So it had to be replaced.

I wanted to build a single board motor controller from scratch, but couldn’t find the parts I needed with the support for the higher current. I decided on a motor driver board from Pololu, and designed my own ‘daughter board’ to connect to it.

The daughter board is an Arduino board of my own design. It mates directly with the Pololu driver board, and included the pin headers for motor encoders, and a connector for a Dimension Engineering voltage regulator. The regulator will be providing the 5V rail for all the electronics in SAGAR.

I have several copies of the daughter board if anyone wants them. They are yours for free but you pay shipping. Leave a comment if you would like one.

Here are some pictures: (click for full size)


Some more pictures:

The old Motor Driver. I feel like it was such a messy job now.

With the Voltage and Current Sensor

Installed. Man it looks sexy!

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  1. 16 Comments.

    • Joker94No Gravatar says:

      One of those boards would be awsome. count me in.

      if i make the cut, do you take PayPal?

      or if not bank transfer?



    • Ro-Bot-XNo Gravatar says:

      Hi MadSci, I would like to try out one of your boards, and perhaps take a look at your controller code. I guess you’re using serial to communicate with it, I will need I2C, but I guess that is not so hard to add, the pins are already grouped together and don’t need pull ups.

      Cheers! And keep up the wonderful work you do!

    • BillNo Gravatar says:

      Hey guys, shoot me an email bill@[the address of my website here] with your address and i’ll calculate shipping.

    • kasNo Gravatar says:

      Hi Bill,

      I did received the card, let me thank you again for your nice attitude.

      I can’t find the part list on your site, is the info available ??

      I made some test with the Pololu motor driver, please see
      I found the Amp monitoring output (CS) to be _very noisy_ did you notice this point ??


    • BillNo Gravatar says:


      Your right! No parts list or assembly guide. I’ll have to write one up tonight.

      I bought the cheaper Pololu driver that does not use the CS current sensing pins, so I don’t know how noisy they are. My driver board doesn’t monitor current either, but you can jumper the pins to the analog pins if you want to add current monitoring.

    • BillNo Gravatar says:

      Parts as promised:

      All resistor values are marked on the board.

      C1 100nF
      C2 10uF
      C3 100nF
      C4 100nF

      The DIP chip in the middle is an Atmega 328

      The three terminal oval component next to the Atmega is a ceramic resonator (crystal replacement). Here’s a 16Mhz model:

      I’ll post the circuit diagram next.

    • BillNo Gravatar says:

      BTW guys, be careful programming this with a sparkfun FTDI board. I didn’t add any circuitry to ‘select’ which power source the board will use, and that cause problems. I just removed the 5V pin from the FTDI header and always used the battery power when programming the Arduino.

    • AndréNo Gravatar says:

      HI! man nice work.. do you still have any of those boards? if so I would love to test one in my little project…

      Best of lucks with your project

    • BillNo Gravatar says:

      I do have more. if you would like one email me motor[at]

    • JeffNo Gravatar says:

      I was wondering if you had any more boards available?

    • G.ANo Gravatar says:

      Hi Bill your proyect is very interesting, I was wondering you left any daughter boards?


    • TejasNo Gravatar says:

      Hey even we are working on a similar project in which we want to interface the playstation joystick with a arduino board. but m not able to figure out how to read values from the sticks please help me out.

    • Joann IrbyNo Gravatar says:

      Hi,Iam working on an arm project.The PID program
      may help me alot.I would love to have one of your SUGER PCB. Thanks a lot!

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