[TriEmbed] I need a circuit that can do this.....

Tue Jun 21 21:20:23 CDT 2016

That part looks like it should work.  You need to be careful of stray
feedback from the output to the inputs so no rats nests of jumpers and you
need a 0.1 uF ceramic cap shorted across the VDD and ground (like right on
them not just nearby).

The LEbar (pin 5)  comes from your uP and you need to code it so it  is
high when you are reading the latch, which may be a problem if the uP is
asleep and all pins go low.  So you may need and inverter for that pin.
You could use another comparator if you do not want to order a CMOS
inverter.

Maybe you can find another comparator with LE instead of LEbar?

Cheers,

>  [TriEmbed] I need a circuit that can do this.....
> All,
>
> OK, before you say it, yes, I first consulted Google before sending this
> note.  I have not worked with these devices before and the latch operation
> is the part that I find most confusing. The best device I could find was
> the MAX9141
> <https://datasheets.maximintegrated.com/en/ds/MAX9140-MAX9144.pdf> but
> the operation of the latch in figure 2 was not what I expected.
>
> I am looking for a simple circuit which will do the following:
> - Powered, Vcc, by either 3.3V or 5V and should not consume more than
> 100uA.
> - Connect to the analog output  (ranges from 0 to Vcc) of my Ultrasonic
> Range Finder <http://www.maxbotix.com/Ultrasonic_Sensors/MB7363.htm> with
> a high input impedance - potentially with a low-pass filter - we will see.
> - Allow me to set a “trigger threshold” ( 0 to Vcc) using a potentiometer
> - Compare the input to the trigger and provide a latched digital “high”
> when the input exceeds the threshold
> - This signal will wake the micro controller using a hardware interrupt
> and trigger an interrupt routine.
> - The comparator will hold the line “high” input until cleared by the
> micro controller
>
> Anyone who has a few minutes to take a look please let me know:
> - Is the part I found the right one?
> - Is there a better solution - perhaps using discrete components?
>
>
> Thank you,
>
> Chip
>
>
>
> ---------- Forwarded message ----------
> From: Shane Trent <shanedtrent at gmail.com>
> To: Chip McClelland <chip at mcclellands.org>, TriEmbed Discussion <
> triembed at triembed.org>
> Cc:
> Date: Wed, 22 Jun 2016 01:49:59 +0000
> Subject: Re: [TriEmbed] I need a circuit that can do this.....
> Chip,
>
> Have you considered tying the range finder output to one of the AVR's
> comparator inputs and a setting the trip point with a pot voltage divider
> on the other terminal?
>
> https://www.avrprogrammers.com/howto/comparator
>
> Shane
>
> On Tue, Jun 21, 2016 at 8:49 PM Chip McClelland via TriEmbed <
> triembed at triembed.org> wrote:
>
>> All,
>>
>> OK, before you say it, yes, I first consulted Google before sending this
>> note.  I have not worked with these devices before and the latch operation
>> is the part that I find most confusing. The best device I could find was
>> the MAX9141
>> <https://datasheets.maximintegrated.com/en/ds/MAX9140-MAX9144.pdf> but
>> the operation of the latch in figure 2 was not what I expected.
>>
>> I am looking for a simple circuit which will do the following:
>> - Powered, Vcc, by either 3.3V or 5V and should not consume more than
>> 100uA.
>> - Connect to the analog output  (ranges from 0 to Vcc) of my Ultrasonic
>> Range Finder <http://www.maxbotix.com/Ultrasonic_Sensors/MB7363.htm> with
>> a high input impedance - potentially with a low-pass filter - we will see.
>> - Allow me to set a “trigger threshold” ( 0 to Vcc) using a potentiometer
>> - Compare the input to the trigger and provide a latched digital “high”
>> when the input exceeds the threshold
>> - This signal will wake the micro controller using a hardware interrupt
>> and trigger an interrupt routine.
>> - The comparator will hold the line “high” input until cleared by the
>> micro controller
>>
>> Anyone who has a few minutes to take a look please let me know:
>> - Is the part I found the right one?
>> - Is there a better solution - perhaps using discrete components?
>>
>>
>> Thank you,
>>
>> Chip
>>
>> _______________________________________________
>> Triangle, NC Embedded Computing mailing list
>> TriEmbed at triembed.org
>> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
>> TriEmbed web site: http://TriEmbed.org
>>
>
>
> ---------- Forwarded message ----------
> From: Chip McClelland <chip at mcclellands.org>
> To: Shane Trent <shanedtrent at gmail.com>
> Cc: TriEmbed Discussion <triembed at triembed.org>
> Date: Tue, 21 Jun 2016 21:59:46 -0400
> Subject: Re: [TriEmbed] I need a circuit that can do this.....
> Shane,
>
> Wow, I did not know this was an option.  The only problem is that I
> believe the only interrupt pins that can wake the Arduino from sleep are
> the D2 and D3 pins and this requires Analog pins.  Please correct me if I
> am missing something.
>
> I can see this being useful in other applications it even supports
> hysteresis.
>
> Thanks,
>
> Chip
>
>
> On Jun 21, 2016, at 9:49 PM, Shane Trent <shanedtrent at gmail.com> wrote:
>
> Chip,
>
> Have you considered tying the range finder output to one of the AVR's
> comparator inputs and a setting the trip point with a pot voltage divider
> on the other terminal?
>
> https://www.avrprogrammers.com/howto/comparator
>
> Shane
>
> On Tue, Jun 21, 2016 at 8:49 PM Chip McClelland via TriEmbed <
> triembed at triembed.org> wrote:
>
>> All,
>>
>> OK, before you say it, yes, I first consulted Google before sending this
>> note.  I have not worked with these devices before and the latch operation
>> is the part that I find most confusing. The best device I could find was
>> the MAX9141
>> <https://datasheets.maximintegrated.com/en/ds/MAX9140-MAX9144.pdf> but
>> the operation of the latch in figure 2 was not what I expected.
>>
>> I am looking for a simple circuit which will do the following:
>> - Powered, Vcc, by either 3.3V or 5V and should not consume more than
>> 100uA.
>> - Connect to the analog output  (ranges from 0 to Vcc) of my Ultrasonic
>> Range Finder <http://www.maxbotix.com/Ultrasonic_Sensors/MB7363.htm> with
>> a high input impedance - potentially with a low-pass filter - we will see.
>> - Allow me to set a “trigger threshold” ( 0 to Vcc) using a potentiometer
>> - Compare the input to the trigger and provide a latched digital “high”
>> when the input exceeds the threshold
>> - This signal will wake the micro controller using a hardware interrupt
>> and trigger an interrupt routine.
>> - The comparator will hold the line “high” input until cleared by the
>> micro controller
>>
>> Anyone who has a few minutes to take a look please let me know:
>> - Is the part I found the right one?
>> - Is there a better solution - perhaps using discrete components?
>>
>>
>> Thank you,
>>
>> Chip
>>
>> _______________________________________________
>> Triangle, NC Embedded Computing mailing list
>> TriEmbed at triembed.org
>> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
>> TriEmbed web site: http://TriEmbed.org <http://triembed.org/>
>>
>
>
> _______________________________________________
> TriEmbed mailing list
> TriEmbed at triembed.org
> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
>
>
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