26mm FET+7135 Driver - MTN-26DDm - 1S Input Voltage

This 26mm FET+7135 driver features an ultra low resistance FET that gives you near-direct-drive performance (limited mostly by your battery, LED, and connections) with the ability to still use lower power levels, among other functions such as low voltage protection.

Some firmware options use only the FET and not the 7135.  They are labeled below.

For the 2S+ version driver, click here.  

Wires + Spring Option

There are four different options for how you would like your driver to be configured:

1. Driver Only - No Spring or Wires - Generally ships within 3 business days
2. Driver + Wires Installed - No Spring - Generally ships within 3 business days
3. Driver + Spring - No Wires - Generally ships within 3 business days
4. Driver + Wires + Bypassed Spring​ - Generally ships within 3 business days

FIRMWARE OPTIONS (FET+7135)

guppy3drv Clicky Firmware (attiny25)

This is the newest update of the guppydrv series by DrJones, now with more modes than ever and thermal protection!  For more information, click this link.

Please note that you set your own turbo timer / temperature sensor setting on guppy3drv.

Bistro Clicky Firmware (attiny25)

ToyKeeper hit this one out of the ballpark!  This is similar to the BLF A6 firmware, but with a lot more options. For more information, click this link.

Standard Clicky Firmware (attiny13a)

• Standard FET with Memory.  This is the most popular option.  Equipped with off-time memory, mode changes are intuitive and the light always picks right back up where you left off. 
  • Mode Levels:  Moonlight - 2% - 5% - 20% - 50% - 100%
• Standard FET with No Memory.  This is the second most popular option.  Equipped with off-time no memory, the light will always start on the first mode level after being turned off.  
• Custom Mode Levels.  Choose your own mode levels.  For this option, please enter the following information in your checkout comments:  
  • 1.  Number of light levels: 1-6 (plus moonlight if desired)
  • 2.  Approximate PWM levels of each mode:  Example: (1) 2% - (2) 15% - (3) 40% - (4) - 100%
  • 3.  Memory or No Memory

Clicky Pin Functions.  Soldering these numbered pins to ground will enable these features:

• 3 reverses mode order from the standard ascending (low to high) to descending (high to low).

Standard Clicky Firmware Low Voltage Protection.  At around 3V under load, the light will blink three times then step down the power level.  At around 2.8V under load the light will blink ten times then shut off.  This system gives you ample warning and attempts to extend runtime before turning the light off. 

BLF A6 Clicky Firmware (attiny13a)

For more information about this firmware, click here.

guppydrv DUAL Clicky Firmware Option

For more information about this firmware, click here. 

Electronic Switch Firmware Options (attiny13a)

• Standard FET Electronic Switch.  This is for use with an external electronic switch, where the driver is always powered, not for use with a standard clicky switch where power is cut by the switch to change modes.  This option uses STAR momentary firmware, which allows you to start on either the lowest or highest mode from off with either a short tap or long press of the switch.  
  • One side of the switch is soldered to ground, the other to the pre-tinned switch pad on the driver (connected to pin 2).
• Custom Mode Levels.  Choose your own mode levels.  For this option, please enter the following information in your checkout comments:  
  • 1.  Number of light levels: 1-6 (plus moonlight if desired)
  • 2.  Approximate PWM levels of each mode:  Example: (1) 2% - (2) 15% - (3) 40% - (4) - 100%
• Not recommended for use with the Zener Mod option (see below).

​Standard Electronic Switch Firmware Low Voltage Protection.  At around 3V under load, the light will step down the power level.  At around 2.8V under load the light will shut off.  You can override any low voltage shut down by holding down the electronic switch button.  This system gives you ample warning and attempts to extend runtime before turning the light off.  

Firmware Options (FET Only)

Universal guppydrv Clicky Firmware Option (Revs. 1 & 2)

For more information about this firmware, click here. 

moppydrv Multi-Group Electronic Switch Firmware Option

For more information about this firmware, click here. 

Electronic Switch Firmware Options (attiny85)

• D4 V2 Ramping.  This momentary switch firmware gives you awesome ramping control, thermal throttling, and a slew of other features.  For more information about this firmware and user interface, click here.  Source code available here.  

Turbo Timer

A turbo timer may help reduce the chance of overheating.

Bistro / guppydrv / moppydrv / D4 V2 firmwares do NOT use a fixed turbo timer. 

 Available Options:

• No Timer
• 30 Seconds
• 60 Seconds
• 90 Seconds
• 120 Seconds
• 180 Seconds

FREQUENTLY ASKED QUESTIONS:

1. What Is The Input Voltage Range?

• 2.5V-4.35V 
• This is a "direct drive" driver, meaning it doesn't step up or down voltage that the LED sees.  This driver can only be used with a single cells on the input (or multiple parallel cells) and a single XM-L2/XP-G2/XP-L/Nichia/etc. on the output (or multiple LEDs in parallel).  
• The MCU (the computer that controls the driver) has a voltage limitation of 5.5V.  This means that it can only be used with a single cell unless zener modified.  

2. What Are the Downsides vs. A linear driver, such as the QLITE?

• No Regulation.  The amount of light the higher modes put out will drop as the battery drains, where with the normal 7135 driver all modes will be regulated until the battery level drops below the point of regulation.
• Heat.  While the driver itself doesn't produce very much heat at all (actually runs cooler than a 7135 driver), you need to be aware that not every LED and every setup can handle the heat and current from running direct dirve.  Running more current also generally means shorter battery life.  This amount of current can also melt switches and springs if they aren't up to the task.  It also generally requires LEDs mounted on direct thermal path MCPCBs.

3. What Kind Of Output Can I Expect?

• Output is generally limited by cell selection, LED type, and other connections (such as springs and emitter wires).  

This driver was made possible and is heavily inspired by many members of the BLF flashlight community, especially comfychair (initial concept and development), Mattaus (PCB layout and development), JonnyC (firmware), DrJones (firmware), and wight (singe-sided PCB development and advice).  If you'd like to learn more about these drivers, and participate in further development, come visit our community at budgetlightforum.com 

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