Solenoid Start Gate Circuit

Solenoid start gates make for consistent heat starts.
*5 J's*
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Re: Start Gate

Post by *5 J's* »

Start gate all wired and video of it in operation. Works great!
(Note - I temporarily "installed" the timer at the end of the first section of track for this test, so it's a short run. Video from my camera so it's low quality).

Image

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FatSebastian
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Re: Start Gate

Post by FatSebastian »

5J's, what was your final investment in terms of components (not counting the solenoid that didn't work out)?
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Re: Start Gate

Post by *5 J's* »

Total was $32.29 + shipping + cost of mounting hardware. Note this included the cost ($5.25) of a 12.5V AC adapter which many may have laying around and therefore wouldn't need to purchase. The total also includes the cost ($10.00) for 36 inches of aluminum angle and I only needed 7 inches. I am using the balance to make a solenoid gate for our Pack track as well as other projects such as shims to be used with the DerbyWorx Pro-Body Jig.

12Vdc AC adapter $5.25
2.5MM DC JACK, PANEL $2.20
Circuit protector $0.34
3300uF capacitor $1.60
12V Solenoid $5.50
Diode $1.00 (pack of ten)
N-channel MOSFET $0.55
100k resistor $0.50 (pack of ten)
N.O. momentary switch $1.00
RJ-11 Jack $1.00 (for two - used a coupler from Dollar Tree)
Aluminum angle $10.00 (36 inches)
Clamp for capacitor $0.75
Elbow latch $0.60
Strike plate $2.00 (pack of 5)
Miscellaneous stainless screws/washers/nuts ??
I did go a bit extravagant and used #10 threaded brass inserts into the melamine board track for mounting the timer. These cost $0.75 each or $3.00 for the four of them.
Note the start gate switch for the MicroWizard Timer was integrated into this start gate but is not necessary for the operation. This switch and 50 feet of cable were $10 from Microwizard.

If anybody makes this - be advised that the mounting tab of the MOSFET is common to the drain (or high potential lead). This means you need to insulate the MOSFET from the aluminum bracket (and mounting hardware). Given the duty cycle the tab doesn't need to dissipate much heat, therefore doesn't require a heatsink, so I just wrapped the tab (and a bit of the mounting screw) in electrical tape.
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Re: Start Gate

Post by *5 J's* »

With all the testing and tuning in the last week I have a couple hundred cycles on the solenoid start gate. Working like a charm. :D
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Re: Start Gate

Post by TimInOhio »

So, I just stumbled across this project. I had been considering another version, the schematic for which is a lot more complicated. Has anyone tried this method on a Best track? No reason it shouldn't work there, right? The solenoid doesn't care what kind of release it is pulling.

Any thoughts?
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Re: Start Gate

Post by SirStorm »

I am holding off on investing in a solenoid starting gate until I see the plans for the car return and the automatic car loader.
=)
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Re: Start Gate

Post by habcdb »

What voltage is the 3000uF Capacitor? I am assuming the 50v. I am attempting to build something similar to this.

Thanks
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Re: Start Gate

Post by *5 J's* »

TimInOhio wrote:So, I just stumbled across this project. I had been considering another version, the schematic for which is a lot more complicated. Has anyone tried this method on a Best track? No reason it shouldn't work there, right? The solenoid doesn't care what kind of release it is pulling.

Any thoughts?
Yes - I am using this on a BestTrack now as well.
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Re: Start Gate

Post by *5 J's* »

habcdb wrote:What voltage is the 3000uF Capacitor? I am assuming the 50v. I am attempting to build something similar to this.

Thanks
I used the 50V cap
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Re: Start Gate

Post by habcdb »

*5 J's* wrote:
habcdb wrote:What voltage is the 3000uF Capacitor? I am assuming the 50v. I am attempting to build something similar to this.

Thanks
I used the 50V cap
Ok, Thanks That is what I ordered.
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Re: Start Gate

Post by *5 J's* »

I thought I had already posted this but couldn't find it. While the solenoid works just fine - this door actuator has a longer throw making it easier to adjust. It was a bit harder to mount however.
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Re: Start Gate

Post by habcdb »

*5 J's* wrote:I thought I had already posted this but couldn't find it. While the solenoid works just fine - this door actuator has a longer throw making it easier to adjust. It was a bit harder to mount however.
I have already built on manual start gate for a single lane best track and used this solenoid
http://www.mcmaster.com/#catalog/119/1013/=l0vp5h" target="_blank

70155K49

It worked well and plan on using it this time.

Thanks
CDB Racing
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Re: Start Gate

Post by habcdb »

Stupid question, but want to make sure I wire it right. Which side is the top on the Q-mosfet? It looks the same from the top and bottom. It wiil make a big difference.
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Re: Start Gate

Post by TimInOhio »

*5 J's* wrote:Below is a circuit for a start gate operated by GPRM via the serial port.

12Vdc will be supplied via a 12Vdc AC adapter (500mA or greater). Most people probably have one kicking around or you could order one such as this 12Vdc AC adapter. Note which size plug it is using. This one is using a 2.5mm, so I would need a 2.5mm female jack such as this 2.5MM DC JACK, PANEL MOUNT.

C1 is a 3300uF capacitor and is used as low-pass filter to clean the 12Vdc power.

S1 is the solenoid. I have two options. This one has a 1/4" pull or this door lock actuator which has a 3/4" pull. NOTE: Solenoid did not have enough power - ordered this one instead

D1 is a diode and is reversed biased in the circuit. It is used to shunt the current developed as the field of the solenoid collapses.

Q1 is an N-channel MOSFET and is used as the switch.

R1 is a 100k resistor and is used to prevent noise for triggering the MOSFET.

D2 is another diode and is used to prevent current flow towards the serial port on the computer.

I have also incorporated a normally open momentary switch (SW1) that can be used to "manually" operate the solenoid.

Image

Operation is as follows: The +12v will be applied to the circuit but will sit on the drain of the Q1 MOSFET. GPRM will send the open start gate command to the gate on the MOSFET via pin 4 of the DB-9 connector. One this voltage is applied to the gate of Q1, Q1 will allow current flow from the drain to the source. This will activate the solenoid, allowing the start gate to open. Once GPRM stops sending voltage to the gate of Q1, Q1 will stop conducting and the solenoid will return and it's collapsing field will be shunted via the D1 diode.
5 J's, do you have specifics for the MOSFET, so I can check my local Radio Shack? The part you link to is a 55V, 22A, .06 ohm - but Radio Shack doesn't have anything matching those specs.

I mocked-up an order from your source, but am looking to see if I can avoid having to pay to ship the parts from CA.

Thanks for any info you can give me.

Tim
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Re: Start Gate

Post by habcdb »

http://www.derbytalk.com/viewtopic.php?f=5&t=2448" target="_blank

http://web.archive.org/web/200710291453 ... matic.html" target="_blank

Radio shack part number 276-2072. This is the one I used, but do not mount it to an aluminum box without isolating it from the box. It will trigger the switch or ground out. Not sure which, but it would activate the solenoid when the metal base of the switch touched the box. The box was grounded.
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