<div dir="ltr">Chip,<div><br></div><div>I believe you can also set the comparator to trigger an interrupt. The example code at the link shows them using the comparator interrupt.</div><div><br></div><div>Shane</div></div><br><div class="gmail_quote"><div dir="ltr">On Tue, Jun 21, 2016 at 9:59 PM Chip McClelland <<a href="mailto:chip@mcclellands.org">chip@mcclellands.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">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><div style="word-wrap:break-word"><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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