Ok thanks, found it. Yes I know that I can adjust the levels manually, but in previous drivers I had trouble to find the right values for a linear increase in brightness.
Anyway, I have another problem with this driver. I build another one but now with a zener mod for a light with a XHP50 and rear clicky.
I flashed the same firmware as on the non zener modded driver and now the mode switching is totaly buggy. It seems it switches at random, sometimes I need to half press the button like 10 times to get it to switch. It also sometimes starts in moon mode and stays on for around 10sec and than switches off. Sometimes it cycles through the modes high to low and sometimes low to high … and so on.
Do I need to change some values in the firmware for zener modded drivers?
Yes. And you may need to change some of the resistors too, if you want any voltage-related functions to work. Or it might need voltage-related stuff turned off entirely.
The PWM levels will also need recalibration for each type of emitter, since the relative contributions of the FET and 7135 change. A single-channel driver can usually get by with one set of levels for all emitters, but two-channel drivers need the firmware reconfigured/rebuilt for each.
(if a light maxes out at 4amps, the 350mA channel can handle 8.75% of the total, but the 350mA channel can only do up to 2.3% on a 15-amp light… and the relative balance should be updated in the firmware to account for this)
The offtime-cap firmware can give you values for CAP_SHORT; just half-press the button for the amount of time you want to set as the threshold between short and long presses, take a few readings, get an average.
As for resistor values, I can’t really help. Battcheck doesn’t provide resistor values; it only provides ADC values to use after you’ve already gotten the resistors worked out. You need to divide the voltage in hardware to get it completely in the range of 0.1 to 1.1V though. Battcheck can at least tell you if you’re getting usable values though; try it with a full battery vs a low battery, and if the values are too close to each other (or if any readings are 255), then the resistors are wrong.
Am I understanding correctly that all the components for this board are the same as the single sided FETDD board with the exception of the 7135 chip? I just piggy pack the zener on the 10uf cap, and flash with the dual PWM firmware?
I may forget more than I remember . Haven't done a zener mod in a long time, though I know it's a combo of the resistor and firmware values read in. Would the 30-40K work for 3 cells as well, and just tweak the values in firmware also?
Depending on your required voltage cutoff, 36K will still work with 3S cells.
Recall the simple voltage divider formula (for these newer drivers without the diode voltage drop):
(Desired Voltage * R2 * 255) / ((R1 + R2)*1.1) = ADC Value
Where the 255 is the highest possible value (which is true, since we are using 8-bits worth of resolution) and 1.1 is the reference voltage.
So in your case, you'd get the following for a 9V LVP ADC value:
9*4700*255 = 10,786,500
(36000+4700)*1.1 = 44,770
10,786,500/44,770= 240.93--round to 241.
OK, now we know the math and understand what's going on. For those who don't like to slog through the math every time (like myself ) I created a Google sheet that you can just punch the values into.
P.S. As many here have noted, the voltage divider resistors can, and will, affect the off-time timing. You'll find that with the zener-mod setups the divider's effect is minimal (the circuit is different).
Ohhh - thanx again Richard! I know you posted this stuff before, but this time I'll really tag it/copy it some where I won't forget . Frustrating - just can't get to all the mods I want to... Limited time, and my mod sessions are much shorter now because of several things goin on - neck, back, access to my modding office, etc.
The voltagedivider consumes “standby” current so for electronic switch lights it might be recommended to use higher values like 100k and 22k as a standard…
Has anyone compared the so8 fets? Is the 0R9 one worth the dollar more?
What resistor Sizes are optimal for this driver 0805 or 0603?
I’m not sure what kinds of files Eagle uses, but the OSHpark page linked in the first post has a link to download a zip containing a bunch of design files. gtp, gts, txt, dri, gbl, gbo, gbp, gbs, gko, gpi, gtl, and gto. Not sure what each one is, but maybe something in there will be sufficient?
The .dri file says it was generated by “EAGLE CAM Processor 7.1.0”.