# Need assistance with a motion/wave sensor to control two solenoids in unison.

#### Smith5821

Joined Sep 21, 2022
3
I am currently working on a project that is using two solenoids that will pull and hold closed by the wave of a hand. The solenoids would hold closed until a hand is waved again max closed time would be around 3 mins. I am having trouble finding a sensor that will work with the solenoids that I am using.

The solenoids that I am using are BAOMAIN BM-Z05
12VDC
2A Current

I was hoping to be able to use something as simple as the hand wave sensors that are used for LED lights although I have been unable to find one that works properly or can handle the current.

I do have some experience with using Arduino but was hoping I could find a simpler solenoid controller or system, if Arduino is the simplest way to handle this, I would be willing to go that route.

#### LowQCab

Joined Nov 6, 2012
2,501
There are 2 separate systems that need to work together,
the heavy-Current-Switching and Spike-Suppression,
and the Hand-Sensor, and Timer.

What is the distance-range that the Sensor must work within ?,
close-sensing, ( within ~6-inches or so ), is easy and cheap,
I don't know how to approach working with greater distances reliably.
It also makes a huge difference if this must work outside, rather than indoors.

Do the Solenoids need to slam-shut hard and fast,
or would it be preferable to have them operate smooth and easy ?

Do You need an automatic "time-out"/"release" after the ~3-minutes max time ?

Is this project going to be Battery-Powered ?
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#### Smith5821

Joined Sep 21, 2022
3
Short distance detection would be all that is needed less than 6 inches would work just fine. Looking for someone to wave their hand a few inches above the sensor to activate/deactivate

The solenoids do not need to slam shut but quickly would be preferred.

The time out really is an after thought just to keep the solenoids from over heating if closed for long periods of time. If possible it would be a time out release only if it wasn't released already before that time.

The plan is to use an AC/DC power adapter one that goes from 120v to 12v.

Although battery operation would be an improvement as long as the battery wasn't very large. I would have room to fit a battery that is around 2" x 4" x 1".

#### LowQCab

Joined Nov 6, 2012
2,501
A Battery would be very expensive, require regular re-Charging,
and would require the addition of a Timer-Circuit.

If your Solenoids will reliably operate when wired in series,
I would recommend that You run them that way.

The following Circuit will work at a minimum of ~12-inches,
and may work up to ~5-feet away,
therefore the LEDs and the Digital-IR-Sensor must face vertically to prevent
false activations from people walking nearby.
If the operation is too sensitive,
the LED-Resistors can be changed to a larger value to reduce their Current.

The Activation-Zone is extremely narrow, it's approximately ~10-degrees wide,
this will reduce the likelihood of false-triggers.

The IR-LEDs, and the Sensor, must not be able to "see" each other,
they must be recessed into drilled-holes,
or the sides must be shielded by some other means.

The FET should be mounted to a convenient chunk of Aluminum,
or mounted in a small Aluminum-Box,
but it should not get noticeably hot with only a ~4-Amp-Load.

I don't know what condition the Output will be in on initial Power-Up,
if that's an issue for you,
the FET can also be driven by the "Not-Q" Output of the Flip-Flop,
which will make it Power-Up in the opposite condition.
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Hand Wave Project .........

IR-LED Vishay-5850,

DigiKey p/n VSLY5850-ND, 10 for ~$10.oo, 2.25V @ 50ma, 850nm-Peak-Wavelength, 5mm-Dia., Max-Current = 100ma, 4 LEDs in series = ~9-Volts Forward-Voltage, = 62-Ohm Current-Limiting-Resistor for ~12-Volt Supply, IR-Detector OPL820 DigiKey p/n 365-1868-ND, ~$3.45
~12-Volt Supply, 800nm-Peak-Wavelength,
5mm-Dia., Hermetic-Metal-Can-Package,

Flip-Flop, CD4013BE,
DigiKey p/n 296-2033-5-ND, 10 for ~$5.25 or 0.60-cents each Heavy N-Chan FET, DigiKey p/n IRFP064NPBF-ND, ~$3.25 each,
Infineon Technologies p/n IRFP064NPBF
55V, 110A, 200W, TO-247-Package,

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#### Smith5821

Joined Sep 21, 2022
3
Thank you very much for this detailed design, I will order the parts and get to work. Will follow up and let know how the project comes along.

#### graybeard

Joined Apr 10, 2012
52
Can I trouble you to explain why you chose the 100K ohm/1uF circuit at the gate? I assume it slows down the solenoid activation by about 100mS or so, correct? I have never done that when controlling a solenoid.

#### LowQCab

Joined Nov 6, 2012
2,501
It's a very easy way to slow-down the FET,
this also reduces the kick-back-Spikes from the Solenoids and almost makes them quiet.
If You want, or need, snappier-response, just reduce the value of the Capacitor,
or leave it out entirely, it's not required for anything else.
Edit ...... I was being lazy, I didn't actually calculate the ramp-time with those values, just a guess.
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#### graybeard

Joined Apr 10, 2012
52
Thanks for the explanation. Makes sense. Learned something new today.

#### LowQCab

Joined Nov 6, 2012
2,501
You can replace the Resistor with a 100K Trim-Pot for fine-tuning the Speed.
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