infrared obstacle avoidance sensor problem

Thread Starter

cbart52

Joined Feb 23, 2020
13
The sensor shown in post #16 does not include a relay. That means that relay coil current is not an issue. So now there is confusion on my part. previously there was reference to a relay, and also a circuit that included a relay. If it is just the current through the comparator output resistor then that resistor can be replaced with a higher valued one and feed an external gate to provide compatible drive outputs.
Correct Misterbill2, the sensor itself does not include a relay. If you refer to the schematic in post #5, the sensor is being used to trigger a separate relay. If I understand you correctly, you are saying to replace the resistor I am using that is shown in the schematic in post #5 with one of higher value. When you say an external gate, does that mean a relay? Also, prairiemystic mentioned an issue with sunlight that makes me think I should be looking at passive IR sensors versus active IR sensors. The location definitely will be in the sunlight at times.
 

MisterBill2

Joined Jan 23, 2018
6,967
NO, when I use the term "gate" it means exclusively an IC logic gate. To reverse the logic sense in your application this could be as simple as one section of a CD4049 hex inverter. That part does not consume much power, and it will be quite happy running on either 5 volts, 12 volts, or even 15 volts. And the main power consumption is during that brief time when it is changing states. If the required control function requires using the states of other functions then consider different kinds of gates, such as AND, NAND, OR, and NOR. With that kind of logic it is entirely possible to duplicate any relay function at much lower power levels, and in much smaller volumes. But you will need to download the data sheets on the components tobe able to understand how they work.
 

Thread Starter

cbart52

Joined Feb 23, 2020
13
NO, when I use the term "gate" it means exclusively an IC logic gate. To reverse the logic sense in your application this could be as simple as one section of a CD4049 hex inverter. That part does not consume much power, and it will be quite happy running on either 5 volts, 12 volts, or even 15 volts. And the main power consumption is during that brief time when it is changing states. If the required control function requires using the states of other functions then consider different kinds of gates, such as AND, NAND, OR, and NOR. With that kind of logic it is entirely possible to duplicate any relay function at much lower power levels, and in much smaller volumes. But you will need to download the data sheets on the components tobe able to understand how they work.
I will research this option. Thank you!
 

RobNevada

Joined Jul 29, 2019
61
An infrared sensor like the one that you used has to have multiple signals before activating. This appears to be a time delay but is really signal processing. You might look at a time of flight sensor and see if you can work it into your project. It would stop at a given distance.
 

MisterBill2

Joined Jan 23, 2018
6,967
An infrared sensor like the one that you used has to have multiple signals before activating. This appears to be a time delay but is really signal processing. You might look at a time of flight sensor and see if you can work it into your project. It would stop at a given distance.
Even the very most simple "time of flight" sensor will consume far more power than the one shown so far. Since the main concern has been battery draw, TOF does not seem like a usable option.
 

Thread Starter

cbart52

Joined Feb 23, 2020
13
An infrared sensor like the one that you used has to have multiple signals before activating. This appears to be a time delay but is really signal processing. You might look at a time of flight sensor and see if you can work it into your project. It would stop at a given distance.
Thank you for your input. When I refer to a time delay, I am referring to how long the sensor stays triggered after there is no longer any object. The passive sensors I have can be adjusted but 5 seconds so far seems to be the lowest I can get it. That is why I was looking at the active IR sensors. There function seems to be immediate. At least as immediate as I need. Hand goes in front of sensor, sensor triggers. Hand goes away, sensor no longer triggered. no time delay. If I could figure out a way to configure the passive sensors so there was no time delay, it may suffice.
 

Thread Starter

cbart52

Joined Feb 23, 2020
13
Yes, I am definitely needing to conserve battery power.
While I've got your attention, you folks are all rockstars. I have a lot to learn about this type of electronics. Can anyone recommend a good text book or other resource so I can better understand what the heck you are all talking about? Thanks
 

ebeowulf17

Joined Aug 12, 2014
3,274
While I've got your attention, you folks are all rockstars. I have a lot to learn about this type of electronics. Can anyone recommend a good text book or other resource so I can better understand what the heck you are all talking about? Thanks
Many of the rockstars here were professional EEs for decades before retiring. In addition to books, you'd probably need many, many years of experience, and quite possibly a university degree in the field, to ever hope catch up with them!

Having said that, we've all got to start somewhere. What little I know is mostly self taught through a combination of manufacturer datasheets, mfr. app notes, reading this forum, and using Google searches as needed. This website also has an online textbook that takes you through the fundamentals in a logical order:
https://www.allaboutcircuits.com/textbook/

There's also a lot of great info at the "electronics-tutorials" website, although I'm noticing for the first time that it doesn't appear to be in any logical order right now. I thought I remembered them having a logical lesson plan, but maybe not:
https://www.electronics-tutorials.ws/

I'm sure there are also lots of great books on the subject, but I can't personally vouch for any. I'm sure someone else will have book recommendations for you.

I almost forgot one - the Adafruit website has really helpful tutorials on many subjects, although they tend to be very product or project specific. Still, if it's your first time working with a specific type of device, they may have a well written tutorial for just what you need.
https://learn.adafruit.com/
 

MisterBill2

Joined Jan 23, 2018
6,967
Yes, ten years as an electronics hobbyist followed by six years total college followed by 45 years in the industrial test equipment business does provide a large bank of experience to draw from. And having done a lot of system diagnostics and service provides some handy insights as well.
 
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