TTL Laser upgrade, almost there, need a few questions answered.

[dindunuffin]

I have an older board on my Elecks A3 laser engraver, its an L5, it has one two pin plug for power, three four pin plugs for stepper motors, and one two pin plug for laser.  I recently purchased a TTL laser from banggood and I'm ready to install it.  From reading the forum, its obvious that I need to run the laser with the provided power supply, my question is in regard to controlling the TTL portion of the laser.  Can I simply connect the laser output from the board to the input on the laser?  I read somewhere that I would need to get the TTL from the D11 pin, where ever that would be located.  OR would it be easier and better to order a newer control board?  Anybody performed the TTL upgrade that would know? I can provide pics if this wasn't clear.

[Zax]

Yes you'll need to get the PWM output from pin D11, have a look under the Nano and you'll see a jumper. The end pin on the 0.9 side is what you need. You'll also need a ground which should be available on one of the connectors, not the laser output as that's switched.

[dindunuffin]

Thanks, I think I can manage that.  Is there a newer control board that would be plug and play, maybe offer some other benefits? I've seen the mansa boards.  Just curious.

[Zax]

None that really offer any benefits, they all use the same Arduino Nano clones. The Mana boards use a Chinese version of the Atmel chip, which I would avoid based on the number of problems.

[dindunuffin]

Chinese knockoff chips? yeah, I'll pass.  Don't all the newer kits come with TTL?  How are they sending the signal?

BTW, you said to NOT use the laser ground pin, so just use any of the other ground pins? the power ground or one of the servo grounds?

[Zax]

I don't remember what the L5 looks like but any of the grounds is OK, except the one on the laser connector as that's switched by the MOSFET.

If you just want to make connection easier get a Mana board or one of the newer designs (yes 95% have a TTL output) and move your Nano from the L5 to the new board.

I like the Cronos Maker boards, that's what I use on my CNC with a remote pendant. It operates off line from an SD card but I don't know if it would be fast enough for a laser controller. It's perfect for a CNC as it has a high current relay for the spindle as well as a MOSFET and TTL outputs.

[dindunuffin]

Thanks for the info. For now I will just tap the D11 pin, but might look at a new board for the future. 
There is this transition module for sale too. I'm assuming that is exactly its purpose.
https://www.banggood.com/EleksMaker-PWM-TO-TTL-Module-for-Laser-Machine-Controller-Board-Mana-SE-IVAxis-p-1245920.html?cur_warehouse=USA

[Zax]

That board separates the power from the TTL so you can run higher powered lasers that require current greater than the Mana board can source.

[dindunuffin]

Under my nano there are three pins, mine has a jumper that jumps the center pin and the 0.9 pin.  It appears that my D11 path runs to the center pin (see pic), but you indicated to use the end pin on the 0.9 side.  Having said that, do I need to keep the jumper in place AND tap the pin(s) too? Since the jumper connects the middle pin with the 0.9 pin, can I just attach the wire onto the jumper, or just remove the jumper and solder all three together?  Sorry, for so many questions, but I want to make sure I don't fry anything.

I was reading an older post of yours..  https://benboxlaser.us/index.php?topic=2383.0  where you were discussing 2-pin vs. 3-pin connectors and TTL. This confused me as my laser is definitely TTL, but it only has two pins on the board (see pic). I understood from your post that 2-pin is non-TTL, and the 3-pins are TTL.  Sometimes reading too much leads to confusion, I'm there.

[Zax]

No, the D11 is on the outer pin. The middle pin goes to the MOSFET gate and can be left disconnected (jumper off).

This is what you are trying to achieve.

Your laser has 4 pins actually; power (12VDC) and ground, TTL (5VDC/PWM) and ground. If you are using a single power supply only 1 ground is required, hence the 3 wire minimum for TTL.

[ggallant571]

In the beginning there were two primary laser control schemes:

1. The 2-wire interface where the power transistor was located on the controller board such as your L5.  This worked OK as long as the current stayed withing the capacity of the board trace, switches, etc. The laser module contained electronics to convert the pulsed 12V power to the constant current signal required by the diode. The fan was typically powered by the switched 12V so it was OFF when the laser was inactive.

2. A 4-wire interface where an intermediate board had connectors for power (12V, GND) and laser control (TTL ON/OFF, GND). It typically has two output ports. One of the 2-wire laser and one for the fan. Advantage is the fan is ON when 12V is present. Disadvantages were extra board and need to have external power switch. Often times you needed to make sure the two grounds were wired together.

You can buy both of these today. A couple of years ago along came the 3-wire setup (Signal, +12V, GND). Works good until you exceed the current requirements. My newest  laser(15W) uses the 4-wire setup that I fudge to fit my 3-wire controller by splicing wires.

BTW - one of my 4-wire modules has the grounds connected, the other doesn't. No place in the hobby laser game are the words "standards" "quality" "interchangable" to be found.

[dindunuffin]

Thank you guys so much, if it weren't for you guys I'd burn this thing up for sure. 

I got sidetracked for a year or so on 3D printing, now I'm coming back around to my laser etcher and its almost like starting over.  So much has changed, new boards, new lasers, Zax has so many software upgrades, I'm going to have to go back thru the manual from top to bottom. I probably should have left well enough alone, but I really want to be able to have the TTL ability.

One last thing for now is there anything I need to do to the old nano except flash it with the new code from T2laser?  I know my firmware is out of date and doesn't have the new GRBL that T2 requires for some of its features.

[Zax]

No, just upload Grbl 1.1e DEFAULT from the Machine menu.