SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
View Poll Results: What’s the most important thing to you?
Lowest possible cost 3 23.08%
Make it as small and light as possible 6 46.15%
Battery longevity is very important 3 23.08%
Highest power possible 3 23.08%
Highest RPM possible 2 15.38%
Only use through hole construction 2 15.38%
No winding of transformers 4 30.77%
Group buy of components including boards 0 0%
Group buy of boards only 1 7.69%
I’d rather buy a kit with everything in it 0 0%
I want to buy a pre-built & pre-programmed system 0 0%
I only want to use a 4.8v Ni-MH battery 2 15.38%
I only want to use a 2S battery 1 7.69%
I only want to use a 3S battery 1 7.69%
I want to use a 4.8v battery to 3S battery 5 38.46%
I want to use only off the shelf parts from Digi-Key or Mouser 3 23.08%
I want the Timer board to be separate from the HV board 6 46.15%
I want a combination Timer & HV board 1 7.69%
I want all the options possible using jumpers 3 23.08%
I want a USB connection 2 15.38%
I want a serial connection (DB9) and I’ll use my own USB adapter 3 23.08%
I want a ICSP connection 3 23.08%
I want a premade parts list (BOM) at Digi-Key 2 15.38%
I want a premade project parts list (BOM) at Mouser 1 7.69%
I want 1 design and 1 design only 1 7.69%
I want optional designs to choose from and Ill make the boards myself 8 61.54%
Multiple Choice Poll. Voters: 13. You may not vote on this poll

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Old Feb 07, 2015, 10:06 PM
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Joined Dec 2012
166 Posts
clones and fakes

http://codeduino.com/information-and...-fake-arduino/
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Old Feb 08, 2015, 09:23 AM
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JoseLuis28's Avatar
Colmenar Viejo - Madrid - Spain
Joined Jan 2009
304 Posts
Ok, I see.

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Old Feb 08, 2015, 06:28 PM
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Nav_Aids's Avatar
Canada, MB, Winnipeg
Joined Nov 2011
338 Posts
I know you were thinking of using the 1840 for pulsing the step-up transformer, did you try a circuit yet? Sparky-1 is a good circuit because everything is broken out as much as I could do it. It is a good teaching circuit. Using a 12F1840 or a MC3406 to pulse or turn the primary current on/off is better but, they are more complicated to use.

I have seen circuits that use 1or 2 transformer/s and 1 or 2 caps to boost the voltage higher (like 1300v). The biggest problem is the charging time, this is where the Time Constant of a capacitor comes in. Also the step-up transformer must be able to handle the charging current and the power supply must be able to deliver the current. Almost all CDI ignition coils will quit sparking when the primary voltage on the coil drops to 100-120v. As the RPM goes up there is less time to charge, eventually you hit a point where you can no longer charge the caps up fast enough. 1.3Kv should be good for @ 60,000 RPM on a 1 cylinder 2 stroke engine and 15,000 RPM on a 4 stroke 8 cylinder all CDI. Also 1.3Kv is hard to control and keep in the wires, furthermore do we need that much energy?

I am a big fan of SMD components but, unfortunatly most hobbyists and DIY's aren't, so keeping this in mind I try to make all my shared circuits through-hole (PTH). With SMD there are more parts available and they are smaller.

Temperature has very little effect until about 75C when you might start to see something, at 105C caps will start to fail and at 150C transformers will start to fail. I constantly monitor temps when I'm testing and if the temps get to high I change the design. I would like to put a RTD in the exhaust to have the 1840 montitor exhaust temps.

Ray

Quote:
Originally Posted by andso View Post
hI, Ray
i think the only 1 I.C. on sparky is good: have a minime qty of comps because the transfo take a big place. i 've investigate about the12F1840 which could do the job,
with a soft space for extra(s) feature(s). But there is to experiment a soft!
I think exploit this 1300V transfo implicate have 2 capacitors ( 600V) and a switching mode of 2 sparks (usefull on big bore, i think large), or only two!, but with an always efficient energy ( a charging cap and a firing cap) (i know, more comps, but have a (semi)SMD approach would be great).
More about the SMDs cook hand book , ¿JoseLuis28 ?
The pulse_routine would take a sense...

Edit about the space: the energy stocked in capacitor(s) is space defined (and dependant of the technology), how to store it (the energy) in a minimal space, is a question;
and how to manage the space ? with elegance!

Edit 2: and i think the energy which have to be stored decrease with the temp (important) and with the RPMs ( a consequence).
Why dont have sparky monitoring the energy needed, with temperature informations?

pj
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Old Feb 09, 2015, 05:10 AM
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United States, ID
Joined Sep 2011
859 Posts
Quote:
Originally Posted by Nav_Aids View Post
I know you were thinking of using the 1840 for pulsing the step-up transformer, did you try a circuit yet?
I've been thinking of trying just that. The charge cycle is linked to the firing cycle, so it might work well to fire the spark then charge the cap.

There's a couple potential problems though. If we charge before the SCR turns off then we'll have problems. I'm also not sure how easy it will be to get everything working right since there will be a lot going on at once.

One thing I found with my quasi-resonant experiments is that it's pretty easy to control primary current through timing, and it's not hard to get ZVS using preprogrammed delays. I'm not sure if this will hold throughout a range of input voltages, but if it's close enough I would think there should be no problems.
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Old Feb 09, 2015, 08:06 AM
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Nav_Aids's Avatar
Canada, MB, Winnipeg
Joined Nov 2011
338 Posts
Quote:
Originally Posted by jakestew View Post
I've been thinking of trying just that. The charge cycle is linked to the firing cycle, so it might work well to fire the spark then charge the cap..
Hi Jake, I tried that, blanking the charging during the sparkplug firing and found that the maximum RPM dropped quite a bit due to the delay of components turning on and off so I just removed blanking.

Quote:
Originally Posted by jakestew View Post
There's a couple potential problems though. If we charge before the SCR turns off then we'll have problems. I'm also not sure how easy it will be to get everything working right since there will be a lot going on at once..
Since we are using isolated transformers, at least from what I've seen, there is no need to blank the charging, The SCR will turn off, because the SCR is effectively shorting out the secondary side and almost no load will be applied to the primary side because it is isolated from the secondary side. The only thing keeping the SCR turned on is the voltage across the capacitor and once that drops low enough the SCR will turn off and the cap will start recharging as long as the trigger is removed.

Quote:
Originally Posted by jakestew View Post
One thing I found with my quasi-resonant experiments is that it's pretty easy to control primary current through timing, and it's not hard to get ZVS using preprogrammed delays. I'm not sure if this will hold throughout a range of input voltages, but if it's close enough I would think there should be no problems.
If you take a look at Sparky-1 & Sparky-2 you will see the difference on how the primary side of the step-up transformer is connected. On Sparky-1 it uses the center tap of the primary and on Sparky-2 it uses the whole primary side. The difference is mainly how the switching is applied. In Sparky-1 the switching is: Upper half of transformer is on, delay, upper half off, delay, lower half on, delay, lower half off, delay, and back to upper half. In Sparky-2 it is: On, delay, off, delay, and back to on. As you can see, using a setup like Sparky-2 would be easier to program.

To calculate the R/C or L/R time constants for charging and discharging of coils and caps and to calculate the delay:
Simple explanation: http://www.learnabout-electronics.or.../dc_ccts45.php
More complex explanation: http://en.wikipedia.org/wiki/RL_circuit

For coil charging use the inductance of the primary side and the resistance of the transistor or IGBT or whatever you are using to turn the circuit on & off.

For coil discharge it depends on which coil we are talking about but, use the resistance of the components on the secondary side only.

Ray
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Last edited by Nav_Aids; Feb 09, 2015 at 08:36 AM. Reason: R/C and L/R Time Constants to calculate Delay
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Old Feb 12, 2015, 11:39 AM
frenchy
France, Pays de la Loire, Chalonnes-sur-Loire
Joined May 2013
64 Posts
i use
a toroidal transfo 220V/12V 4VA producing H.T. for experiment , and that's sufficient to spark on a 125CC motor. I think on sparky1, the CCFL (1300V 6W) is not exploited at its max. I have posted a calc sheet to explain that if the voltage doubles the energy squares and the value of the capa(s) can be smaller, the challenge for the rc purpose!

There are 650V CCFL: but difficult to find on the market... I have now two on a samsung supply card( ccfl ref TM-2326 HYD750DCI), but they are big (maybe 14W), .
http://www.plcforum.it/f/topic/17572...o-video-aiuto/
PJ
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Last edited by andso; Feb 12, 2015 at 03:21 PM. Reason: small is beautiful
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Old Mar 03, 2015, 05:03 PM
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Joined Jul 2014
106 Posts
If you would like to build, rather than buy, an Arduino type development board, here is an Open Source site for the "Pinquino;" based on PIC18F2550:
http://www.hackinglab.org/pinguino/index_pinguino.html
It is also documented for a 18F4550 version.

Also do searches for "Pinquino" and "18F4550 Bit Wacker." You will find lots of additional information.

I have created a "stick" style, double sided, 18F4550 development board... See attachment. I call it "The Sandwich." It is about 3.5" x 1.25." The folder has Eagle files. (I am not the author of the circuit, just the board layout.)

If you have questions, please send me a private message, so we don't end up highjacking this thread...

T
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Last edited by Tee One Dee; Mar 05, 2015 at 04:47 PM.
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Old Mar 04, 2015, 09:15 AM
frenchy
France, Pays de la Loire, Chalonnes-sur-Loire
Joined May 2013
64 Posts
Hi Tee One Dee
excellent!
i' m looking for a domotic solution (some n.t.c. and relays), and that would be a choice.
In parallel, i want a mini usb/B on my C.D.I., and my choice for the interface is actually on the MCP2221, from microchip also, but i have not statued.

Sometimes this site is difficult to domesticate... (i had problem of time-out with multiple tabs opened in firefox...
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Old Mar 04, 2015, 04:13 PM
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