Use for the Tesla Switch

[citfta]

Hi jpolakow,

Welcome to the forum and the TS thread. Do not remove the varnish. The laminations are supposed to be insulated from each other to keep down eddy currents. Eddy currents waste energy and cause heating of the transformer. Matt has said several times that you need to wind the wire onto the form as neatly and tightly as possible. Some of the guys have made a wooden form to fit inside the plastic sleeve so it is not crushed as you wind the wire on tightly. Some of the other guys may be able to give you more advice that have come up with better ways of doing the winding.

Carroll

[jpolakow]

thanks cifta

Thankyou so much Carrol! l I really appreciate your advice. I will wind as carefully as possible.

John

[hiops]

Hi, Matt and all! I got my parcel from digikey on Friday with small transformer and Basic Stamp 2E, took apart the transformer already and ready to rewind it, but haven't got #20 wire yet.
The Stamp kit comes without cable, can anyone give the part # for it on digikey or mouser, meanwhile I'm going to solder it.
One more question to Matt: can we insert transformer into the top wire between positives of Bat1 and Bat3, that way we need only one primary wound? We could use a bigger wire with that, b/c we need only two wounds here.

[Matthew Jones]

You just need a USB to serial cable.
Sabrent 1 Ft USB 2.0 to Serial DB9 Adapter w/Male Thumbscrews at TigerDirect.com

You do not want to pull a load from the the hot side of the batteries. Adds to many complications.


@ALL

Have a good one its been a nice ride I might pop in from time to time. Remember look for the truth. Believe what it tells you.

Matt.

[LutherG]

You just need a USB to serial cable.
Sabrent 1 Ft USB 2.0 to Serial DB9 Adapter w/Male Thumbscrews at TigerDirect.com

You do not want to pull a load from the the hot side of the batteries. Adds to many complications.


@ALL

Have a good one its been a nice ride I might pop in from time to time. Remember look for the truth. Believe what it tells you.

Matt.

Man, I sure am bummed to see this post Matt... I hope you do visit and often. I appreciate all you've shared with us. I'll be posting my results soon. I've got my Stamp on order as of Friday so I should get it by the end of the week.

Thanks again for all the hard work you put in to share your findings with us and I hope you reconsider and stick around a little longer... but if not, I wish you all the very best.



Luther

[gandyman]

Hmzz I have blow up my Propeller chip, with a faulty power supply...

Have order a few new ones ad Paraalax.... SIG

[citfta]

Hi gang,

I have talked to Matt and he is ok with me trying to help those of you who are sincerely trying to follow his PDF plans for building his version of the TS. I realize a lot of you do not have much or any electronics experience. IF you are trying to build Matt's TS then I am willing to help with the electronics. If you think you know more than Matt about building a TS then you are on your own. If you go back to the beginning of this thread you will see that Matt has been at this for a long time. Study the PDF Matt made. Then if you have questions about how something gets hooked up ask and I'll try to help if I can. Most of your questions have already been answered in the last several pages of this thread. I only have time to check in here a few times a day so don't expect an immediate answer to your questions. I have over 50 years experience in electronics but I can still make mistakes or typos just like anyone else. You are totally responsible for your own safety as I can not be there to make sure you don't do something stupid. Use fuses as I described in an earlier post.

Carroll

[garrypm]

Hi,

I can confirm that I am getting much better output with a fresh set of batteries.

A couple of questions remain -

1. From Matt's document, we see mention of the 400Hz switch (news article)
and with my meter measuring AC from the secondary (9.8v), the meter
shows approximately 200Hz if I set the delay in the Arduino to 2000us. To
get 400Hz at the output, I need to reduce the delay to 1000us or there abouts.
I Know my maths are a bit rusty but, if we set a pin high then wait 1000us
and then set the pin low and wait another 1000us then repeat, the cycle
would be 1/period = 1/2000us = 500Hz
At 2000us, 1/4000us = 250hz.
This is a bit confusing because the STAMP guys use PULSEOUT and
the ARDUINO guys must set High, wait, then set low and wait again.

Can anyone clarigy this for me?

2. One transistor from the pair of ONLY one set is getting warmer than the
oher three (Matt's darlington schematic). Should I just replace the transistor
(MJE13007) or is this somewhat expected ?

Thanks, Garry

p.s. anyone getting better than expected results and can I ask what size 12v
bulb are you guys using - mine is a 5 watt.

[jpolakow]

Mounting circuit components

Hi Caroll,
I have a couple electronics questions for you if you don't mind. I'm going to school for EE at CalPoly so I understand circuit theory, however my technical, "hands on" electronics skills are weak. So here are a few questions I have building the switch.
1. I have a breadboard and a few other "prototyping" boards but none of them seem to fit the pin spacing of the capacitors, diodes, or transistors. Is there a special socket you are supposed to buy for these components to fit into? Or are you supposed to drill holes for the components in the proto board? Or do you design a pcb for the application?
2. I reviewed the documentation and it seems the output winding of the transformer that is 25% longer goes to the rectifier and then to the load. Is this correct? I want to make sure before I start soldering stuff up.
3. My first build is the small switch. I am planning on building the big switch as well. I'm going to need car batteries for the big switch, so I'm going to need to get them eventually anyway, would they work with the small switch as well? I mean I realize its a battery so it will work, but the smaller switch uses a smaller load- possibly too small a load to effectively reduce the voltage on the batteries for tuning purposes?
4. On the back of the SSR and MJL21194 I see a heat conducting pad on the back. Is it neccesary to heat sink these components?

Thankyou very much for your assistance. This is probably common knowledge for some people but I'm kind of an electronics newb! I am taking many pictures and will document my build so others may have an easier path to follow. Have a good day!

John

[citfta]

Hi John,

I do not use proto boards for my builds. They are notorious for getting bad connections and causing circuits to not work. I use perboard. You can get it at Radio Shack in several sizes. I get the kind that has .1 inch spacing between the holes. Most transistors like the TO 220 style have the pins on .1 spacing already. I just mount the parts by putting the pins through the holes in the perboard and bending them over to make my connections. I just find a convenient layout for my parts so that I can connect them together with as few jumpers as possible. If you do a little planning with your layout of parts you can usually just bend the pins on the bottom side of the board and solder them to one another. You will probably need a few jumpers but not many if you plan carefully. Use sockets for your IC chips like the opto couplers. You can easily damage a chip while trying to solder to them. You may still have to drill a new hole here or there depending on the components you are using. And you may have to enlarge a hole for some parts that have larger than normal leads.

The output leads go to the AC side of the bridge rectifier and the DC side of the rectifier goes to the cap and the load is connected to the plus and minus of the cap.

I think if you use car batteries on the small switch you may have a hard time seeing what is going on. I am using some lawn and garden tractor size batteries on my small switch and that seems to be about right to give me some good run times and still let me see what is going on with them.

@ Garry, I am not familiar with the Arduino. I am using the picaxe 18x. I can tell you a couple of things though. A cycle or hertz is one complete set of pulses. In other words you pulse one side and then the other and that is one cycle. You do not want a pause between pulses. You will get some delay just from the program running. And that delay time needs to be as close to the same for each pulse for best results. There is an earlier discussion a few pages back for how to get the delays the same. I may have misunderstood from your description but it sounded like you were putting a delay between the pulses. Also you do not need to try and get an exact frequency based on what someone else has done. Follow Matt's instructions for tuning to get the best output and charging of your top batteries. Everyones build is a little different so the best frequency will be too.

I am using a 6 watt bulb in my TS so you are pretty close. You may have one transistor getting warmer than another for a couple of reasons. If one battery bank is charged up more than the other then it may be working harder. You could have something in the circuit not quite right somewhere or maybe a weak transistor. If it is only getting a little warmer and not hot then I wouldn't be concerned about it.

Later, Carroll

[dnewkirk]

I Know my maths are a bit rusty but, if we set a pin high then wait 1000us and then set the pin low and wait another 1000us then repeat, the cycle would be 1/period = 1/2000us = 500Hz
At 2000us, 1/4000us = 250hz.
This is a bit confusing because the STAMP guys use PULSEOUT and the ARDUINO guys must set High, wait, then set low and wait again.

2. One transistor from the pair of ONLY one set is getting warmer than the
oher three (Matt's darlington schematic). Should I just replace the transistor
(MJE13007) or is this somewhat expected ?
p.s. anyone getting better than expected results and can I ask what size 12v
bulb are you guys using - mine is a 5 watt.

Hey Garry,
I’m not one to offer better advice, but I can tell you what I have experienced so far. I have the BS2 STAMP setup and haven't played with the Arduino. I suspect that the execution times for each line of code are close to each other. Even though you have to execute more commands with the Arduino to acomplish what PULSOUT does on the BS2, the vast majority of the time is spent during the delay period of the pulses. So the +/- differences in the hundreds of microseconds between the two setups becomes negligible when using millisecond delays to adjust frequency.
On the STAMP for example, Pulsout the first pin at say 4100, which equates to about a 8200us pulse duration. This pulses the Primary1 winding, which puts the first alternation out the secondary winding. Then the next line of code pulses out another pin which controls the switching of current to Primary2 winding, which causes the other alternation to be output on the secondary winding. The two "pulsout" commands complete one cycle. Their combined delay period is theoretically 16400us (16.4msec). You would think the output frequency would be 1/.0164, or 60.975Hz. But it is closer to 60Hz because of the extra delay introduced between lines of code and their execution times. Not much more, but enough to bring the output freq down a bit.
I'll be changing over to a PIC microcontroller chip to take advantage of the ADC capabilities.
But whether you're using the arduino, a STAMP, a PICAXE, etc; the setup schemes are basically the same, and we all should get similar results when using comparable xfmrs, load wattages, and battery sizes. I'm currently using a 12v, 6 watt load. I've just obtained four new garden tractor batteries at 275 cranking amps. True wet cell lead acid batts. I'll be using my same small xfmr, but will change the ckt over to the sziklai pair switches. I bet I'll get better results than the first test with the Darlington sw setup.

The second transistor of each darlington pair carries better than 95% of the switching current, so you can expect that one to be warmer on each pair. Depending on the load current, characteristics of the xsistors and primary windings, the amount of heat you feel on each pair should be "relatively" close to each other. When they get too warm to keep you finger on them, better heat sink them well! If one gets radically hotter than the others, then look for a problem in your ckt wiring, or the transistor itself is fast on the way to becoming a charcoal briquette. You can quickly see if heat sinking works by using southern engineering... loosely slip a small pair of vise grip pliers around the MJE13007 (or MJL21194) and gingerly screw it tight for a snug fit. It's fast to do and you'd be surprised how well it works. That's all I can think of for now.
Let's keep up the enthusiasm so we can make this a success and help each other with the 'Big One'! --Dennis

[ehsanco1062]

Hi Carroll
I have been playing with the BS2 codes and i found that the best VloadDC across the load I have with
PULSOUT 1, 5100
PULSOUT 2, 5650
But with that PULSOUT I have one Battery start charging and the other one start losing its voltage.
As I understand from Matt that in the end of the test we should have two batteries fully charge and two batteries fully discharge but it seems that this doesn’t happen here, as I said I can charge only one battery when using the codes mentioned above
But when I use these codes
PULSOUT 1, 5000
PULSOUT 2, 5000
I will get less VloadDC across the load and almost no charging for the two batteries.
There is no much here to play with except the BS2 codes so where is the problem and where to look for it seems that I confused a little every thing I have here is ok I have no heat on the transistor nor the transformer and good voltage across the load and I am using 10w load but I am not satisfied with the charging can you help with that I appreciate any help.
Thanks
Ehsan

[LutherG]

Hey Garry,
I’m not one to offer better advice, but I can tell you what I have experienced so far. I have the BS2 STAMP setup and haven't played with the Arduino. I suspect that the execution times for each line of code are close to each other. Even though you have to execute more commands with the Arduino to acomplish what PULSOUT does on the BS2, the vast majority of the time is spent during the delay period of the pulses. So the +/- differences in the hundreds of microseconds between the two setups becomes negligible when using millisecond delays to adjust frequency.
On the STAMP for example, Pulsout the first pin at say 4100, which equates to about a 8200us pulse duration. This pulses the Primary1 winding, which puts the first alternation out the secondary winding. Then the next line of code pulses out another pin which controls the switching of current to Primary2 winding, which causes the other alternation to be output on the secondary winding. The two "pulsout" commands complete one cycle. Their combined delay period is theoretically 16400us (16.4msec). You would think the output frequency would be 1/.0164, or 60.975Hz. But it is closer to 60Hz because of the extra delay introduced between lines of code and their execution times. Not much more, but enough to bring the output freq down a bit.
I'll be changing over to a PIC microcontroller chip to take advantage of the ADC capabilities.
But whether you're using the arduino, a STAMP, a PICAXE, etc; the setup schemes are basically the same, and we all should get similar results when using comparable xfmrs, load wattages, and battery sizes. I'm currently using a 12v, 6 watt load. I've just obtained four new garden tractor batteries at 275 cranking amps. True wet cell lead acid batts. I'll be using my same small xfmr, but will change the ckt over to the sziklai pair switches. I bet I'll get better results than the first test with the Darlington sw setup.

The second transistor of each darlington pair carries better than 95% of the switching current, so you can expect that one to be warmer on each pair. Depending on the load current, characteristics of the xsistors and primary windings, the amount of heat you feel on each pair should be "relatively" close to each other. When they get too warm to keep you finger on them, better heat sink them well! If one gets radically hotter than the others, then look for a problem in your ckt wiring, or the transistor itself is fast on the way to becoming a charcoal briquette. You can quickly see if heat sinking works by using southern engineering... loosely slip a small pair of vise grip pliers around the MJE13007 (or MJL21194) and gingerly screw it tight for a snug fit. It's fast to do and you'd be surprised how well it works. That's all I can think of for now.
Let's keep up the enthusiasm so we can make this a success and help each other with the 'Big One'! --Dennis

Hi Dennis,

There is an ADC chip at parallax that is part of the Stampworks Experimenter Kit - so it should work with your stamp.

Look here:

ADC0831 8-bit A/D Converter DIP

I'll be getting one of these for my stamp. I also ordered a couple of the TI MSP430 Launchpad boards... They're just so inexpensive and run on so little current I've got to give them a try as well... I saw a video on youtube of a guy running one on 3 grapes...

Just wanted to let you know... and yes - agreed - let's keep the enthusiasm going and get this working!

best regards,

Luther

[garrypm]

Guys,

Thanks so much for the replies.

I will double check my wiring and change out the one transistor that is getting
warmer than the others.

Also, getting another 5watt bulb and paralleling the two may help show system
performance in a more timely manner.


To keep things in perspective, the tranfomer used measured 2" x 1.75" x 1.5".
The wire used is 0.8m (20BS) and the primaries are 5 meters and the secondary
is 6.25 meters.

Thanks, Garry

[citfta]

Hi Ehsan,

Well there are several things that you can play with. You are restricting your thinking too much. For instance no one said you had to use a 10 watt load. Maybe a 12 watt load would work better. Maybe a pulseout of 8000 and 8000 would work better or maybe 4000 and 4025. You need to make a chart and try different loads and pulsing times and look for the best charging and best voltage on the load. Then try to find a compromise between the two. Are you putting a delay between pulses? On mine it works best with no delay other than what is caused by the execution of the code. It also works best with both pulses the same. Good luck.

Carroll