I have wired the circuit properly, it just won't ignite on the other end!! - Page 1
Forum section: electronics / beginners

author: cuesoccer24
author_rank: Contributor
timestamp: March 24, 2020, 06:07:51 pm
content: Hello to all,I am trying to build a model rocket launch controller using the shell of an old N64 controller. One guy did it on youtube and I am trying to replicate exactly what he did. I wanted a DIY project since we are staying home from work with the virus out there. I am a beginner with electronics and I just need help wiring this together. I thought I completed the circuit yesterday and when I went to connect the two 9V batteries, nothing happened. There was no connection to the mini push button switch or from the bigger red push button to send power to the mini LED. Not sure where I went wrong, but if someone can help me figure this out/help me wire things together I would be greatly appreciative. The two pictures I have attached are what I am working with. One picture is of the shell of the N64 controller with the parts inside and where they all go. The other is the diagram/schematic of the wiring that I need to complete, I just can't figure out how. Thanks for any info or diagram help.

author: bob91343
author_rank: Super Contributor
timestamp: March 24, 2020, 07:31:30 pm
content: It's not clear what you want to do. Please explain what function you want and which button is supposed to do what.You have connected the batteries in parallel so you still have 9 Volts. It goes through the first button to supply 9V to the second button. When you press the first button, the LED will light unless you install it backwards. While holding the first button, you press the second and the full 9V goes to the igniter. So you need two hands to press both at once, the way you have drawn it.

author: cuesoccer24
author_rank: Contributor
timestamp: March 24, 2020, 08:01:53 pm
content: First of all, thank you for replying to my thread, I really do appreciate your time. Sorry if I wasn't really clear with my post. I wasn't sure of how to really word it since I am a beginner with this stuff.There are 2 functions I would like to have happen.When I would press the big red button on the top of the controller first, this would send the signal to the LED to light up to show I have contact and ready the system. The second button (bottom...gray Z button-mini push button installed inside the controller) would then be triggered to send the signal out to the igniter to light the rocket engine.The big red button opens the circuit and the bottom Z button would close the circuit and send the signal to the igniter?I hope that clears anything up. Explaining it is hard but I tried my best. I included two more pictures.

author: senso
author_rank: Frequent Contributor
timestamp: March 24, 2020, 08:56:25 pm
content: In your original image where it says to igniter, you add the second button, interrupting the signal that already comes from the first button.

author: cuesoccer24
author_rank: Contributor
timestamp: March 24, 2020, 09:52:33 pm
content: Senso...could you explain further? maybe help me with a drawing of the diagram if mine sucks?

author: krappleby
author_rank: Contributor
timestamp: March 24, 2020, 10:10:26 pm
content: HI,from the 9v source to your first switch, Connect this to your resistor and led, Run a wire from here to your - on the battery, (when you press first switch the light will come on but no signal to ignitor)then connect another wire from the resistor (- end) to your second switch, run that directly to your igniter. (when pressed (only if first switch is active and led on, will signal be sent to the ignitor)hope that explains it a little better..Cheers

author: cuesoccer24
author_rank: Contributor
timestamp: March 24, 2020, 11:08:37 pm
content: I appreciate the feedback, I will try that shortly.

author: cuesoccer24
author_rank: Contributor
timestamp: March 25, 2020, 03:55:40 am
content: I figured it out, thanks everyone for your contribution!!

author: bunnyThief
author_rank: Contributor
timestamp: March 25, 2020, 04:07:39 am
content: Did you mix up the terminals on the batteries?

author: cuesoccer24
author_rank: Contributor
timestamp: March 25, 2020, 04:15:17 pm
content: nope, didn't mix them up, just wasn't running the correct wires to certain parts. I was able to connect everything including both switches. I can now open and close the circuit. It is an accomplishment for being a noob with electronics!!

author: cuesoccer24
author_rank: Contributor
timestamp: March 28, 2020, 01:54:06 am
content: So everything is connected and wired properly. I just have one question...why won't everything produce enough electricity to heat the igniter? My batteries are good. I am stumped.

author: bunnyThief
author_rank: Contributor
timestamp: March 28, 2020, 02:13:52 am
content: Quote from: cuesoccer24 on March 25, 2020, 04:15:17 pmHow are you checking that the circuit is closing?

author: bob91343
author_rank: Super Contributor
timestamp: March 28, 2020, 02:30:37 am
content: What are the igniter specifications? Two puny 9V batteries might not be able to supply the required current.

author: Nerull
author_rank: Frequent Contributor
timestamp: March 28, 2020, 02:33:08 am
content: Estes-style igniters are notoriously high current - I've seen all-fire figures of around 2A, it often takes several seconds for them to ignite with disposable battery powered launch systems, and typical club systems use car batteries. Thin gauge wires can also be a problem.Connect the clips to a light bulb and make sure its working at all.Pretty much every other manufacturer uses e-matches that fire at much lower currents, there have been issues with the continuity check function of launch systems built for estes igniters accidentally setting e-matches off.

author: Stray Electron
author_rank: Super Contributor
timestamp: March 28, 2020, 02:49:35 am
content: Quote from: bob91343 on March 28, 2020, 02:30:37 amAbsolutely this. I used to use a 12v car battery and even that wouldn't have enough power to ignite them if I used a long run of wire. I would use something like three 18650 Lithium batteries in series. They can put out a tremendous amount of current for a short time. Also I found that if I dropped two or three grains (pieces not weight) of 2F or 3F Black powder into the nozzle before installing the igniter that that gave me much better ignition. I used a small tuft of cotton loosely pressed into the nozzle to hold the powder and igniter in place.PS also you need to make sure that you're using GOOD switches. The junk sold by Radio Shack and the cheapo switches that just push a copper plate against a wire aren't good enough. Go get a couple of real military surplus switches or some good industrial switches.

author: MarkF
author_rank: Super Contributor
timestamp: March 28, 2020, 02:50:35 am
content: Wire gauge and wire length...You may have too much voltage drop in the wire.Consider dividing it into two pieces:

author: cuesoccer24
author_rank: Contributor
timestamp: March 28, 2020, 04:13:34 am
content: Hello to all,First of all, thank you for your advice and replying to my thread.I'll try to answer as much as I can.bunnyThief: I am not sure how to check for a closed circuit. All I know is that when I push the big red button, this allows me to push the 2nd button (trigger button on bottom of controller) and this lights up the LED. If I were to press the big red button again and then push the trigger button on the bottom, the LED will not light up. Is that what it means when the circuit is opened and closed?Quote from: bob91343 on March 28, 2020, 02:30:37 amThe igniters are estes model rocket igniters. not the most quality built things in the world but its what I had. I am trying to use two 9v but I guess that isn't cutting it.Quote from: Nerull on March 28, 2020, 02:33:08 amHow do I connect to a light bulb? Just touch the wires on the base? sorry if that's a dumb question.Quote from: Stray Electron on March 28, 2020, 02:49:35 amAre those lithium batteries readily available and not too expensive? Thanks for the info. I am using good switches...they seem to work and my LED light turns on.MarkF: Thanks for the diagram...to be honest I am not totally sure how to read it but I will try to figure it out. I am a newbie with electronics.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 28, 2020, 05:35:08 am
content: Brings back memories. Too much current can make the wire explode apart never igniting the little black blob.Basically the system works in two levels, there's a continuity check which lights up a LED/bulb in series with the igniter. If that doesn't light up, there's a problem.Typically after a few launches the clips to the igniter get dirty.AFAIK the igniters are rated for 6V and they rely on the resistance of the long wire to the controller to limit the current.I didn't know model rocketry was still a "thing". When I was doing it people thought nothing of two weird kids with rockets and batteries taking public transit.What kind of rockets are you building? Do they still have the Estes designer's kit?

author: cuesoccer24
author_rank: Contributor
timestamp: March 28, 2020, 05:55:44 am
content: Just regular model rockets from estes...just a build I wanted to do since I am not working right now. These are just simple put them together kits. I haven't had any wires "explode". At this point I kind of wish they would explode to ignite the rocket engines!!

author: krayvonk
author_rank: Regular Contributor
timestamp: March 28, 2020, 07:12:55 am
content: I bet that circuit is right, its just i dont understand why that resistor and led is there, i know its got 500 ohms resistance, but wouldnt that sorta ignite it as well, especially if you put too many batteries in I mean.

author: MarkF
author_rank: Super Contributor
timestamp: March 28, 2020, 09:26:20 am
content: In your first photo, it looks like you are using thin speaker wire.I did a quick look around the web on model rocket igniters and they need a lot of current for a short period of time.At the very MINIMUM, I would use16AWG/2 Lamp Cord.An alternative battery option might be a small 12V motorcycle lead acid battery.Note. I modified my previous circuit with detailed part names (plus a few mods)...Quote from: krayvonk on March 28, 2020, 07:12:55 amThe resistor/LED are there to indicate continuity from the battery through the igniter when the system is armed.From what little I have read, you should be able to safely have less then 100mA current through the igniter without it going off. A typical LED is less than 20mA.

author: MarkF
author_rank: Super Contributor
timestamp: March 28, 2020, 09:58:38 am
content: Single battery (with higher capacity) option:Lots of ways to skin a cat here. Biggest concern is the safety interlocks!

author: cuesoccer24
author_rank: Contributor
timestamp: March 28, 2020, 03:03:32 pm
content: I think I am starting to understand this diagram a little better Mark, thank you for labeling everything.I am using speaker wire and I think it is 10 AWG...would that possibly be the problem with not getting enough current to the igniters?

author: cuesoccer24
author_rank: Contributor
timestamp: March 28, 2020, 03:06:32 pm
content: Hopefully this clarifies anything...I am going to open up the controller in a little bit to show the inside wiring diagram and see what everyone thinks.

author: cuesoccer24
author_rank: Contributor
timestamp: March 28, 2020, 04:42:17 pm
content: Does my wiring make sense?

author: MarkF
author_rank: Super Contributor
timestamp: March 28, 2020, 06:13:30 pm
content: Quote from: cuesoccer24 on March 28, 2020, 03:03:32 pmThe smaller the gauge number the larger the wire size.From your latest photo, that does not look like 10AWG wire. 10AWG wire would be twice the size you've shown.The 10AWG wire would dwarf the small wires used on 9V battery connectors.For 10AWG wire, the copper conductor in each wire is approx. 1/10 inch diameter.Compare that wire to the wire on any lamps you have in your house.Edit. 10AWG speaker wire would be closer to the size of what they use to call 'monster cable'.Each wire with its insulation has a diameter close to 1/4".

author: Nerull
author_rank: Frequent Contributor
timestamp: March 28, 2020, 08:03:56 pm
content: Monster cable is a marketing wank audiophile brand, not a gauge of cable.

author: MarkF
author_rank: Super Contributor
timestamp: March 29, 2020, 12:06:20 am
content: Quote from: Nerull on March 28, 2020, 08:03:56 pmYes. But, I bet most people know what it looks like and how big it is!I actually do not know what gauge Monster cable is or if it is all the same gauge.And that is not what the OP is showing in his photos.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 29, 2020, 01:14:58 am
content: Quote from: cuesoccer24 on March 28, 2020, 05:55:44 amAh, I meant the wire inside the igniter's blob. I remember experimenting with the igniters and a home-brewed SCR+large cap igniter system. At some point the igniter simply exploded apart never igniting properly. There's a sweet spot of current where the filament glows and lights up the blob properly.

author: Manul
author_rank: Super Contributor
timestamp: March 30, 2020, 03:43:24 pm
content: Maybe it is just me, but LED current (even small) going through a control relay, as in the last diagram, makes me nervous.

author: cuesoccer24
author_rank: Contributor
timestamp: March 30, 2020, 03:50:50 pm
content: Quote from: MarkF on March 28, 2020, 06:13:30 pmAbsolutely right with that Mark, not 10AWG at all...it is very thin and I believe it is around 18-20 AWG wire.

author: MarkF
author_rank: Super Contributor
timestamp: March 30, 2020, 06:53:34 pm
content: Quote from: Manul on March 30, 2020, 03:43:24 pmMe too.The sourced relay would need a fairly large coil current to energize for safe operation.Maybe someone can come up with a better circuit configuration that would check continuity with switching operation...

author: cuesoccer24
author_rank: Contributor
timestamp: March 30, 2020, 07:45:13 pm
content: I am all ears...this isn't going the way that I thought it was going to go...I feel like I have the correct wiring and with a resistor it should be safe right?Would anyone be willing to help me with this if I shipped my controller to them to have it fixed? I know that's a long shot but I could really use some help.

author: Manul
author_rank: Super Contributor
timestamp: March 30, 2020, 08:19:38 pm
content: Well, I worked with dangerous stuff myself. Safety is number one thing. Always.Because of that and also because of the fact, that we are discusing kind of "general" approach (we don't know for sure what relay, diode, resistor, battery etc. someone will use), I suggest toput battery, or any kind of power source on a control side.Because wire can short, LED can fail, relay can activate from mechanical shock, you name it. So it is best to remove all these posibilities all together by putting battery on a control side. You can even physicaly disconnect ignition wire from control device, setup everything, go away, connect wire, push your buttons. All other details and problems can be discussed and solved. Should not be very hard to make it work.

author: Manul
author_rank: Super Contributor
timestamp: March 30, 2020, 09:05:31 pm
content: Why not make it simple, similar to how OP started doing:

author: Manul
author_rank: Super Contributor
timestamp: March 30, 2020, 09:23:01 pm
content: Or, if OP wants indication of full circuit readiness (continuity), then this should do. Added reverse diode to protect LED, because most probably there will be significant reverse voltages because of wire inductance. Something like 1N4148 should do.And if it does not ignite and you have a multimeter, measure how much current is going to igniter and compare with igniter specs. That would be some useful basic troubleshooting.Or if igniter specs states just voltage, measure voltage on igniter side (carefully, possibly you want to run a separate wire for that to not be close).

author: cuesoccer24
author_rank: Contributor
timestamp: March 30, 2020, 10:12:41 pm
content: Quote from: Manul on March 30, 2020, 09:05:31 pmI am not totally in tune with the symbols Manul...could you explain what each of those blue and black triangles represent?

author: Manul
author_rank: Super Contributor
timestamp: March 30, 2020, 10:26:10 pm
content: Quote from: cuesoccer24 on March 30, 2020, 10:12:41 pmWell, on the left it is battery symbol. Switch is kinda obvious symbol (connects/disconnects circuit). Resistor is represented by a symbol which looks like spring. Black triangle with two white arrows pointing away is LED (light emitting diode). Blue triangle without white arrows is a diode (it may be optional, but better be there). Here you goThats almost same to what you did in the first place. So read my comment about troubleshooting if your setup still does not work.In my opinion (and others) you just need a good thick wire and correct type of battery. It may be not the 9V battery which you use. You possibly need something more beefy. Or more sensitive igniter. Thats a process of trial and/or measurement.If 9V battery is not enough, ideas would be car battery, UPS battery, battery packs from power tools or RC model batteries.

author: MarkF
author_rank: Super Contributor
timestamp: March 30, 2020, 11:31:47 pm
content: Your original circuit is okay as is.The only real problem is that you might want a 12V battery and larger gauge wire.Check out my earlier link to Lowes 25ft 16/2 lamp cord.As said elsewhere you can check your circuit by connecting a 12V light bulb instead of the igniter.A SPDT switch for arming would make the circuit safer.Edit:I have read a few tests on different igniters requiring as high a 20A for a few milliseconds.This will require a large gauge wire and/or higher battery voltage to meet this requirement.As @Alex Eisenhut said, you might need to experiment to find the sweet spot ofbattery voltage, wire gauge and wire length.Maybe even connecting igniters (Outside of the rocket) to see what combination works best.

author: cuesoccer24
author_rank: Contributor
timestamp: March 31, 2020, 02:36:17 am
content: thank you for the input...i will look into it.Now that I am looking at my controller set up and wire thickness...they all seem to be pretty small, somewhere in the range of 22-30 awg for all wires except the speaker wire. That could be one source of the problem. I also need to find a bigger battery source.

author: MarkF
author_rank: Super Contributor
timestamp: March 31, 2020, 04:54:37 am
content: Quote from: cuesoccer24 on March 31, 2020, 02:36:17 amA quick Digikey search gave this 12V battery:price $16.00, size 3.86" L x 1.91" W x 2.01" Hhttps://www.digikey.com/product-detail/en/panasonic-bsg/LC-R121R3P/2148-LC-R121R3P-CHP/10246377