Your Cart(0)

Sigma Lambda Controller Free

by 14Point7
This product is not available

SLC Free has been superseded by SLC Free 2

his We took our cutting edge SLC design, trimmed away the excess, and gave it wings. The result is a 0.01 Lambda accurate Wideband O2 Controller with a digital display and best of all - it is open source. SLC Free was developed with all the professional tools and calibration gases we normally use to develop our closed sourced WIdeband O2 Controllers so you can be sure that the accuracy, response time, and quality is as good as any Wideband O2 Controller on the market.

SLC Free is easy to assemble and suitable for all experience levels. Generous component spacing, clearly marked component names and values on the circuit board and packaging, a detailed user and construction manual, means anyone can build a SLC Free kit in well under an hour.  

There are 3 variants of SLC Free


Source Code

Bosch LSU Wideband O2 Sensor

Lambda Display

O2 Sensor Temperature Display

SLC Free A GPL v3 4.9 0.68[Lambda] to 1.36[Lambda] bar graph bar graph
SLC Free B Closed 4.9 0.68[Lambda] to 1.36[Lambda] numeric display numeric display
SLC Free C  Closed 4.2 0.68[Lambda] to 1.36[Lambda] numeric display numeric display


Note: SLC Free does not come with cable, you will need to source your own 5 conductor 20 AWG and 6 conductor 20 AWG cable.

SLC Free A Firmware and PCB files is released under the GPL V3 license, available here

Note: If purchased with LSU 4.9 sensor, the included sensor is a Bosch OEM sensor. The "head" of the sensor and it's internal sensing elements are made by Bosch, the cabling and calibration is done by a 3rd party.



Compatible with all fuel types
half space
Lambda Range: 0.68[Lambda] linear to 1.36[Lambda]
full space
0.01 Lambda accuracy without the need for any calibration
full space
O2 Sensor Temperature Monitor 
half space
Did you know that the most common cause of inaccuracies and premature O2 sensor failure is attributed to the O2 sensor temperature being improperly controlled? Only 14Point7 branded Wideband O2 Controllers are able to monitor O2 sensor temperature?
full space
Linear output allows easy interfacing with gauges, fuel management systems, and dataloggers
half space
Linear Output: 0[v]@0.68[Lambda] linear to 5[v]@1.36[Lambda], 10[AFR] linear to 20[AFR] equivalent for gasoline
full space
Simulated Narrowband Output allows you to install a Wideband O2 Sensor in place of your Narrowband O2 sensor 
half space
Switch point @ 1[Lambda], 14.7[AFR] equivalent for gasoline
full space
SLC Free features an attractive 2 line backlight LCD display - displaying Lambda with 0.01[Lambda] resolution and displaying O2 sensor temperature with 1[C] resolution
half space
SLC Free A: Dual Digital Bargraph display
half space
SLC Free B: Dual 3 digit numeric display
half space
SLC Free C: Dual 3 digit numeric display


Software and Documentation
Package Contents
  • SLC Free PCB
  • LCD display
  • preprogrammed microcontroller
  • All electrical components; resistors, capacitors, diodes, fuses, ICs, IC sockets, pinheaders, and connectors
  • Mechanical components; standoff and screws
  •  5 fuse holder
  • 5A fuses
  • LSU connector + contacts + heatshrink

Spartan 2 Compatible Products:

5 out of 5, based on 2 reviews
Hazwan Rahman from Malaysia on Nov 05, 2016
Cheap! Accurate and easy to assemble as long as you know how to follow instructions and know how to solder. Did I mention cheap?
Nicholas M Chang from Jamaica on Jan 12, 2015
Good quality components, easy to assemble, great price and functionality

Share This

1237 Shaw Street Toronto, Ontario M6G3N9 Canada 416-273-5409

We Accept...

We Accept Visa We Accept PayPal