# Electromagnet and IR Beam Sensor project

#### mmccra2858

Joined Jan 12, 2022
18
I need some help, I don't know a lot about electronics, I'm hoping to learn a thing or two. I'm working with my daughter on a school STEM project. The project is a little box with a door held up by an elector magnet, the magnet is to be controlled by an IR sensor. The Electromagnet is powered and holding the door until the beam is broken. The unit is to be battery powered and portable. Any help explaining how to build something like that as well as where to get the components would be greatly appreciated.
The IR sensor only has to work within a range of about 4 inches. The electromagnet would have power to it until the sensor beam is broken, at which point the door, held by the magnet will fall. A small time delay to re-energize the magnet would be necessary.

The links below are from a previous post and were provided by Yaakov back in March of 2019.
I think the components could work for my project, but I sure would appreciate some help putting it together.

Thanks,

https://www.amazon.com/Gikfun-avoidance-Reflective-Photoelectric-Intensity/dp/B07FJLMLVZ/

https://www.amazon.com/dp/B07DFT2WDS/

#### AlbertHall

Joined Jun 4, 2014
11,957
From the answer to a question on the sensor, the range is just 3cm which is quite a long way short of 4 inches.
Could you use a beam break sensor? That would work over a longer range.

#### mmccra2858

Joined Jan 12, 2022
18
From the answer to a question on the sensor, the range is just 3cm which is quite a long way short of 4 inches.
Could you use a beam break sensor? That would work over a longer range.
Yes I'm sure that I could use a beam break sensor.
Thanks

#### sghioto

Joined Dec 31, 2017
3,059
The IR detector in the link is a reflectance type sensor but can be used as a break beam.
What is your idea or how do you plan to break the beam in this project?
Here's one idea: You can use a non reflective surface to break the beam or vice versa.
Any specs or a link to the electromagnet you are planning on using?

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#### mmccra2858

Joined Jan 12, 2022
18
Just a small electromagnet module. Here are the specs on the one I looked up.

Technical Details
• Nominal Voltage: 5V DC
• Current Draw: 0.22 Amps at 5V
• Holding Force: 2.5 Kg / 5.5 lb
• Diameter: 20mm / ~0.78"
• Center Diameter: 8mm / ~0.3"
• Height: 15mm / ~0.59"
• Lead Length: 270mm / ~10"
Product Weight: 25.1g / 0.9oz

#### sghioto

Joined Dec 31, 2017
3,059
Question:
After the door falls and later when the magnet is re-activated how does the door get back up, just manually?

#### mmccra2858

Joined Jan 12, 2022
18
Question:
After the door falls and later when the magnet is re-activated how does the door get back up, just manually?
Yes just manually raising the door. Essentially it's a little spider trap with a clear plastic door, the door will have a metal strip glued onto the surface, for the magnet. The sensor set up will turn off the electromagnet when the beam is broken, allowing the door to fall.

#### MrChips

Joined Oct 2, 2009
25,928
I think that it is unlikely that a spider will trip the sensor unless it is a very large spider.

#### mmccra2858

Joined Jan 12, 2022
18
I think that it is unlikely that a spider will trip the sensor unless it is a very large spider.
School project, a remote control spider will set it off.

#### sghioto

Joined Dec 31, 2017
3,059
The unit is to be battery powered and portable.
What type of battery are you planning on using?

#### mmccra2858

Joined Jan 12, 2022
18
What type of battery are you planning on using?
I was thinking, small battery pack 5 volts.

#### MrChips

Joined Oct 2, 2009
25,928
I was thinking, small battery pack 5 volts.
5V battery packs are not common (except USB power chargers).
Three 1.5V alkaline batteries will give you 4.5V
Four 1.5V batteries make 6V.
Lithium-ion batteries are nominally 3.6V.
You could use any battery voltage with significant capacity and use a switching regulator to give 5V output.

#### sghioto

Joined Dec 31, 2017
3,059
I would suggest 6 volts with a four pack of AA batteries.
How long will this magnet be powered before triggering with the RC spider?

#### sghioto

Joined Dec 31, 2017
3,059
Here's a wiring diagram using the modules posted in #1.

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#### crutschow

Joined Mar 14, 2008
29,508
Current Draw: 0.22 Amps at 5V
Here's where the design rubber meets the road.
You will need a very large battery to provide that current for any significant period of time (look at the ampere-hour (AH) ratings of typical batteries).
Better to use an electric solenoid to momentarily operate and release a latch that closes the door when the beam is broken.
That way the quiescent circuit power will be a lot less.

#### mmccra2858

Joined Jan 12, 2022
18
I would suggest 6 volts with a four pack of AA batteries.
How long will this magnet be powered before triggering with the RC spider?
not long, only long enough for a demo.

#### mmccra2858

Joined Jan 12, 2022
18

#### mmccra2858

Joined Jan 12, 2022
18
Here's a wiring diagram using the modules posted in #1.
View attachment 257622
Hi, I had some trouble getting a timer, I finally found one, I was wondering if you could draw the diagram again using this timer?
Thank you for all your help.

Matt

#### sghioto

Joined Dec 31, 2017
3,059
For that Timer to work in this setup will require adding a relay to the Load terminals.
The Timer module in post #14 is available at Amazon, $11.99 MakerHawk Time Delay Relay, 12V 5V USB Relay Module 6-30V Delay Controller Board Delay-Off Cycle Timer Control Switch with LCD Display Support Micro USB 5V Power Supply Thread Starter #### mmccra2858 Joined Jan 12, 2022 18 For that Timer to work in this setup will require adding a relay to the Load terminals. The Timer module in post #14 is available at Amazon,$11.99
MakerHawk Time Delay Relay, 12V 5V USB Relay Module 6-30V Delay Controller Board Delay-Off Cycle Timer Control Switch with LCD Display Support Micro USB 5V Power Supply
Thank you, I ordered the relay, they said it would be here Friday. Could you show me how to wire it all together?
Thanks.

Matt