complete project

[Tinkerer]

The first picture of the Flyback is good. Symmetric and no truncation.

On the second picture we see oscillations. Not good. Is this the STW18nm80 Mosfet?
Could it be that the power supply does not deliver enough current?
Normally the 2 large capacitors should supply all the current for the TX.

PS. on irfan, you can also rotate the pictures by a few degrees, best before cropping, and re-sample for smaller size.

[mschmahl]

Hi tinkerer,

i have a flyback now. The problem was the 6V supply for TC4452. Now i have 12V and all looks better.
Here are the pictures.


Thanks for your spice-simulation and your help.

[mschmahl]

Thanks for this LTspice-file, tinkerer. I will try it tomorrow. So i hope to find my mistake.

[Tinkerer]

Below is the LTSpice simulation file for the TX and target responses. With this you can see the differences that any change in Flayback capacitance or inductance causes.
You can also see what the different wave forms should look like.

For the induction balance, the important part to look at, is K3 L1 L3 0.25 this means that the surface area covered by the BU coil must be 0.25 times the surface area covered by the TX coil. Use medium coil thickness for the calculations.


Tinkerer

[Tinkerer]

We need to go back to the balancing of the coils. Please see my post on IB coils.

Tinkerer

[mschmahl]

Hello Tinkerer,
can we go trough balance coil´s and settings for R27 and R28? The tinkerer_sb is on with permanent tone in headphones. It doesn´t show any reaction for metall. Here are some scope-shot´s.


I have built in the sn74hc4066n. On Pin 1 and 11 i see the same how on pin 6 from 2019 and on pin 13 and 12 i see the sample from pic. If i touch pin 2 or pin 10 with the scope-probe then the tone is changing higher or lower and one of the led´s glow.

[Tinkerer]

The timing is correct, congratulations!

If you crop the pictures, only to show the important part, they become clearer. Below is a link to a totally free software that works well for cropping and reducing the pictures for sending by WEB.

http://www.irfanview.com/main_download_engl.htm

Tinkerer

[mschmahl]

Sorry for my little report, but i have almost no time for my hobby these day´s.
The two board´s are now complete and all is wired good. The voltages are fine on the socket´s. The PIC is working right. I have made some scope-pictures
for TX ON and OFF and Sample 1 and Sample 2. I have take the probes for TX on Pin 2 of TC4452 socket and on Sample-connection-point on RX-Board.
Next step is building the coil.
Tinkerer thank´s for your tireless help.

[Tinkerer]

Hello Tinkerer,
i have downloaded the MPLAB X but couldn´t use it right. Than i have downloaded PicKit2 Programmer. This was easier to use and i could programm the Pic16F690 with the notification: "successfully". How can i test the pic of proper working?

The TX pin should be ON about 90us and OFF about 10us. Sample 1 should be starting about 5us after TX OFF
Sample 2 should end just before TX OFF.

[mschmahl]

Hello Tinkerer,
i have downloaded the MPLAB X but couldn´t use it right. Than i have downloaded PicKit2 Programmer. This was easier to use and i could programm the Pic16F690 with the notification: "successfully". How can i test the pic of proper working?

[Tinkerer]

Thank´s Tinkerer.
Here is the updated file (only PDF). If someone need the schematic-file for DesignSpark PM me.
I´m soldering the RX-Board on a testboard. I think i will finish it today or tomorrow. Next step´s are programming the pic and building the coil.
For programming the pic i have PICKIT 2 and MPLAB IDE V8.50. What programm did you use? Is the HEX-file up to date?
Greeting´s from saxony.

I use the PICKIT 2 for the programming. Recently I am using MPLAB X. The V8.5 files run on X but I don't know if the other way around.
I have packed my stuff away for moving. In about 6 weeks I will unpack. In the meantime use the Hex file I posted earlier.
For the large coil and deep search, use about 20nF or 2x 10nF Flyback capacitor. This should work with about 10us OFF time.
Later we can optimize the timing for your specific purpose.
All the best
Tinkerer

[mschmahl]

Thank´s Tinkerer.
Here is the updated file (only PDF). If someone need the schematic-file for DesignSpark PM me.
I´m soldering the RX-Board on a testboard. I think i will finish it today or tomorrow. Next step´s are programming the pic and building the coil.
For programming the pic i have PICKIT 2 and MPLAB IDE V8.50. What programm did you use? Is the HEX-file up to date?
Greeting´s from saxony.

[Tinkerer]

Hi mschmahl,

R 13 must be about 100 Ohm, 10 or 20 turns for fine adjustment.

R 6 is better about 47 Ohm, to limit the current that R13 sees. (R6+R13) should be between 47 Ohm and 150 Ohm.

All the best

Tinkerer

[mschmahl]

New PCB for PSU&TX.
Further changes are: - R3 must be a big one with 3W
- Pinswap for -5V and +5V; sample #1 and sample #2; batterie 0V, 6V, 12V and Coilconnection
- allmost all track´s are on the bottom side, only 3 track´s are on top side, so the PCB can be made single-sided



One problem i see is on IC1, the LDO for + 5V supply. It is always on, because ground is 6V and in is 12V and there are no switches to turn off this IC. We could use an additional switch for batterie +6V.

Greeting´s from Saxony

[mschmahl]

@all
I have made some changes around C6, C1 and Coilconnection, but without heatsink for the mosfet (i don´t find one in libary). I think the best ist to solder the coil direct to board for handeling 3 A, therefore are the big pad´s. I have reconnect some part´s on the left, but i have to do it with the ride side.
Greetings from saxony.