BlackBuck 8M PWM Control

[DeathStarLaserGuy20]

I’ve read all the docs I could find on the subject but can’t figure this out. The BlackBuck 8M on DTRs site says it can be controlled via PWM signal but what is really going on? Is that PWM signal actually adjusting the output current or is it just switching the output current on/off fast enough to effectively lower the rms wattage? I suspect the latter as that’s my understanding of modulation.

If it’s just switching on/off does anyone have any thoughts on using a digital potentiometer like a AD5206 to set the maximum output current?

 

[Anthony P]

I can not speak to the PWM. However, I have successfully used a 10k pot for analog adjustment several times with BB8.

 

[paul1598419]

Those 8 amp BB drivers do use a 10K pot to adjust the power level from a set maximum down to no output. But, they aren't PWM modulated.

 

[DeathStarLaserGuy20]

thanks guys. I kept reading on it all night and am convinced the PWM control is just turning it on/off so I’m going to go the real long way around , starting with just a regular 10k pot, and moving onto an Arduino that reads a PWM signal and sets a digital pot. I’ll try to update this post once that’s done.

 

[cncyana]

Just a few questions about analog 10K Ohm potentiometers for use with the BlackBuck 8M:
1) I am looking for a small one with minimal voltage drop/resistance.
2) Linear
3) What pots have been used here on this forum? What characteristics on the datasheet should I look for?
4) Is it ok to turn the pot dial when the laser is on or will it cause 'noise' along the way and put stress the laser diode?

I'm looking at this one:

https://www.mouser.com/datasheet/2/54/50-777299.pdf

 

[farbe2]

I actually made a pcb that uses an encoder to control a BlackBuck8M. It features a RGB LED to display the battery status and can be programmed to have many modes. Like flashing or strobing or SOS. It just needs to be connected to the BlackBuck.
It can also measure the temperature of a laserdiode and turn the power down to not overheat it.

Drop a PN if you are interested!

 

[Anthony P]

Any 10k pot will do. Yes, it can be adjusted under power.

 

[cncyana]

Any 10k pot will do. Yes, it can be adjusted under power.

Thank you for the info!

 

[cncyana]

I actually made a pcb that uses an encoder to control a BlackBuck8M. It features a RGB LED to display the battery status and can be programmed to have many modes. Like flashing or strobing or SOS. It just needs to be connected to the BlackBuck.
It can also measure the temperature of a laserdiode and turn the power down to not overheat it.

Drop a PN if you are interested!

hello, do you have a driver thread on this forum so I can take a look?

 

[farbe2]

Yes I do! Have a look here:

Selling: 3x 2A driver with Userinterface for RGB Control

Hello Guys, I did make a 3 channel driver that can be used as the complete control electronics needed for a RGB laser pointer. Features: - 3 Channel with up to 3x 2A completely spike/surge free - MM config (950mA Red / 2A Green / 1.7A Blue) or SM config (250mA Red / 350mA Green / 250mA Blue)...

laserpointerforums.com

there is also a YouTube video that shows the Userinterface and the different modes. RGB modes are only available for multicolor drivers.
I also build a 3,3W RGB pointer with exactly this driver:

Building a "everycolor" / RGB >3W Laserpointer

Hello guys! I already have a 488nm 55mW pointer. The 488nm served me well and i always wanted a yellow one. But yellow is so god damm expensive that i don't like the idea of buying an DPSS 5mW for a price of a old used car. So one day im gonna build a RGB wich can do yellow and purple. This is...

laserpointerforums.com

Actually this PCB does feature a driver on board and has a different shape. I do have the same thing in rectangular from with plugs for easy connection and without onboard drivers. Its designed to drive a BlackBuck with the same user interface (RGB led + encoder) as the RGB pointer has. I have a picture, however these boards are not cleaned of the solder flux jet, so they look a bit dirty, the ones I sell are clean!

These boards are capable of driving multiple BlackBucks. 3 Control channels are available, meaning RGB would be possible or just a single color.

 

[cncyana]

thank you for the info. I will take a look...

 

[cncyana]

I just got a reply for DTR_ AUG and was told the soft start on the Blackbuck 8M is 0.5ms. Super short, if not instantaneous. It should not be described as a soft start IMHO.

The Barnett site says 300ms.

Is there a spec sheet somewhere to check this? Who built the driver?

 

[cncyana]

I just noticed the Barnett site now says startup delay is 30 ms.
I don't know if I originally misread it as 300ms or if Barnett changed it in the past few days.

If the 30 ms number is correct for the 8M driver, this would mean the BlackBuck ASC4500BU and ASC5500BU drivers have a better soft start = 250ms.

Although the 30ms number applies to the original 8M driver but we are now at Rev.2 so does anyone know what changes were done to make it a Rev.2? Is x-wossee still around?