Re: [beam] Re: Maxibug v3 input needed
- You had me wondering Jack.
The positive feedback cap value together with the 1M
resistor should be tuned to the time constant of
acceleration (determined by robot mass and motor speed) so
that it results in a little wiggle as it moves in straight
line. If the cap is too big, the wiggle will be too big or
the bot may even twirl. With no feedback cap and no resistor
there is probably high frequency switching back and forth
of the motor drive signals which could be wasteful of
energy. With no feedback cap (and stray capacitance alone),
the resistor will help lower the frequency of the switching
but may not be optimum for efficiency. Experiment for best
----- Original Message -----
From: "Jack" <grsshpr875@...>
Subject: [beam] Re: Maxibug v3 input needed
Date: Wed, 22 Sep 2010 23:25:39 -0000
>--- In firstname.lastname@example.org <mailto:email@example.com> ,
>wrigter <wrigter@...> wrote:
>> The schematic has several errors:
>> 1. add a jumper between the negative side of C2 (the
>> reverse cap) and the tactile sensor. When the sesnor
>> closes, the cap is charged up through the contact and
>> when the sensor opens the cap is discharged through R2.
>> 2. remove the jumper between the U1A output and the U1C/E
>> 3. LDR CDS2 should be connected to the output of U1A
>> instead of to the input of U1E.
>> 4. The inputs of U1C and U1E should be connected
>Holy, you aren't kidding! Fortunately I've been working off
>another schematic. This EAGLE version was drawn up hastily
>for posting purposes.
>> 5. The new 1M resistor should go between the common point
>> of the LDRs and inputs of U1C/E.
>> 6. A 0.1uf cap should be connected between the inputs of
>> U1C/E and the output pins of U1D/F
>The 1M resistor works like a charm. No more jitter.
>Movement straight forward is smooth as butter.
>The 0.1uF cap has me confused. Again, my interpretation of
>your instructions here.
>i-1M-balancer\ -v2.jpg> When the cap is connected the bot
>only wheels around in one direction regardless of light
>levels. Besides that I feel the bot is ready for a few pics
>and a video :)