<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small"><br></div><div class="gmail_extra">
<br><div class="gmail_quote"><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small">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).</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small">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. <br></div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small">Maybe you can find another comparator with LE instead of LEbar?</div><br></div><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small">Cheers,</div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> [TriEmbed] I need a circuit that can do this.....<br><div style="word-wrap:break-word">All, <div><br></div><div>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 <a href="https://datasheets.maximintegrated.com/en/ds/MAX9140-MAX9144.pdf" target="_blank">MAX9141</a> but the operation of the latch in figure 2 was not what I expected. </div><div><br></div><div>I am looking for a simple circuit which will do the following:</div><div><span style="white-space:pre-wrap"> </span>- Powered, Vcc, by either 3.3V or 5V and should not consume more than 100uA.</div><div><span style="white-space:pre-wrap"> </span>- Connect to the analog output (ranges from 0 to Vcc) of my <a href="http://www.maxbotix.com/Ultrasonic_Sensors/MB7363.htm" target="_blank">Ultrasonic Range Finder</a> with a high input impedance - potentially with a low-pass filter - we will see.</div><div><span style="white-space:pre-wrap"> </span>- Allow me to set a “trigger threshold” ( 0 to Vcc) using a potentiometer </div><div><span style="white-space:pre-wrap"> </span>- Compare the input to the trigger and provide a latched digital “high” when the input exceeds the threshold</div><div><span style="white-space:pre-wrap"> </span>- This signal will wake the micro controller using a hardware interrupt and trigger an interrupt routine.</div><div><span style="white-space:pre-wrap"> </span>- The comparator will hold the line “high” input until cleared by the micro controller</div><div><br></div><div>Anyone who has a few minutes to take a look please let me know:</div><div><span style="white-space:pre-wrap"> </span>- Is the part I found the right one?</div><div><span style="white-space:pre-wrap"> </span>- Is there a better solution - perhaps using discrete components?</div><div><br></div><div><br></div><div>Thank you,</div><div><br></div><div>Chip</div><div><br></div></div><br><br>---------- Forwarded message ----------<br>From: Shane Trent <<a href="mailto:shanedtrent@gmail.com">shanedtrent@gmail.com</a>><br>To: Chip McClelland <<a href="mailto:chip@mcclellands.org">chip@mcclellands.org</a>>, TriEmbed Discussion <<a href="mailto:triembed@triembed.org">triembed@triembed.org</a>><br>Cc: <br>Date: Wed, 22 Jun 2016 01:49:59 +0000<br>Subject: Re: [TriEmbed] I need a circuit that can do this.....<br><div dir="ltr">Chip,<div><br></div><div>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?</div><div><br></div><div><a href="https://www.avrprogrammers.com/howto/comparator" target="_blank">https://www.avrprogrammers.com/howto/comparator</a><br></div><div><br></div><div>Shane</div></div><br><div class="gmail_quote"><div dir="ltr">On Tue, Jun 21, 2016 at 8:49 PM Chip McClelland via TriEmbed <<a href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">All, <div><br></div><div>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 <a href="https://datasheets.maximintegrated.com/en/ds/MAX9140-MAX9144.pdf" target="_blank">MAX9141</a> but the operation of the latch in figure 2 was not what I expected. </div><div><br></div><div>I am looking for a simple circuit which will do the following:</div><div><span style="white-space:pre-wrap"> </span>- Powered, Vcc, by either 3.3V or 5V and should not consume more than 100uA.</div><div><span style="white-space:pre-wrap"> </span>- Connect to the analog output (ranges from 0 to Vcc) of my <a href="http://www.maxbotix.com/Ultrasonic_Sensors/MB7363.htm" target="_blank">Ultrasonic Range Finder</a> with a high input impedance - potentially with a low-pass filter - we will see.</div><div><span style="white-space:pre-wrap"> </span>- Allow me to set a “trigger threshold” ( 0 to Vcc) using a potentiometer </div><div><span style="white-space:pre-wrap"> </span>- Compare the input to the trigger and provide a latched digital “high” when the input exceeds the threshold</div><div><span style="white-space:pre-wrap"> </span>- This signal will wake the micro controller using a hardware interrupt and trigger an interrupt routine.</div><div><span style="white-space:pre-wrap"> </span>- The comparator will hold the line “high” input until cleared by the micro controller</div><div><br></div><div>Anyone who has a few minutes to take a look please let me know:</div><div><span style="white-space:pre-wrap"> </span>- Is the part I found the right one?</div><div><span style="white-space:pre-wrap"> </span>- Is there a better solution - perhaps using discrete components?</div><div><br></div><div><br></div><div>Thank you,</div><div><br></div><div>Chip</div><div><br></div></div>_______________________________________________<br>
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<br><br>---------- Forwarded message ----------<br>From: Chip McClelland <<a href="mailto:chip@mcclellands.org">chip@mcclellands.org</a>><br>To: Shane Trent <<a href="mailto:shanedtrent@gmail.com">shanedtrent@gmail.com</a>><br>Cc: TriEmbed Discussion <<a href="mailto:triembed@triembed.org">triembed@triembed.org</a>><br>Date: Tue, 21 Jun 2016 21:59:46 -0400<br>Subject: Re: [TriEmbed] I need a circuit that can do this.....<br><div style="word-wrap:break-word">Shane, <div><br></div><div>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. </div><div><br></div><div>I can see this being useful in other applications it even supports hysteresis. </div><div><br></div><div>Thanks,</div><div><br></div><div>Chip</div><div><br></div><div><br><div><blockquote type="cite"><div>On Jun 21, 2016, at 9:49 PM, Shane Trent <<a href="mailto:shanedtrent@gmail.com" target="_blank">shanedtrent@gmail.com</a>> wrote:</div><br><div><div dir="ltr">Chip,<div><br></div><div>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?</div><div><br></div><div><a href="https://www.avrprogrammers.com/howto/comparator" target="_blank">https://www.avrprogrammers.com/howto/comparator</a><br></div><div><br></div><div>Shane</div></div><br><div class="gmail_quote"><div dir="ltr">On Tue, Jun 21, 2016 at 8:49 PM Chip McClelland via TriEmbed <<a href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">All, <div><br></div><div>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 <a href="https://datasheets.maximintegrated.com/en/ds/MAX9140-MAX9144.pdf" target="_blank">MAX9141</a> but the operation of the latch in figure 2 was not what I expected. </div><div><br></div><div>I am looking for a simple circuit which will do the following:</div><div><span style="white-space:pre-wrap"> </span>- Powered, Vcc, by either 3.3V or 5V and should not consume more than 100uA.</div><div><span style="white-space:pre-wrap"> </span>- Connect to the analog output (ranges from 0 to Vcc) of my <a href="http://www.maxbotix.com/Ultrasonic_Sensors/MB7363.htm" target="_blank">Ultrasonic Range Finder</a> with a high input impedance - potentially with a low-pass filter - we will see.</div><div><span style="white-space:pre-wrap"> </span>- Allow me to set a “trigger threshold” ( 0 to Vcc) using a potentiometer </div><div><span style="white-space:pre-wrap"> </span>- Compare the input to the trigger and provide a latched digital “high” when the input exceeds the threshold</div><div><span style="white-space:pre-wrap"> </span>- This signal will wake the micro controller using a hardware interrupt and trigger an interrupt routine.</div><div><span style="white-space:pre-wrap"> </span>- The comparator will hold the line “high” input until cleared by the micro controller</div><div><br></div><div>Anyone who has a few minutes to take a look please let me know:</div><div><span style="white-space:pre-wrap"> </span>- Is the part I found the right one?</div><div><span style="white-space:pre-wrap"> </span>- Is there a better solution - perhaps using discrete components?</div><div><br></div><div><br></div><div>Thank you,</div><div><br></div><div>Chip</div><div><br></div></div>_______________________________________________<br>
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