REM Extra Pin Support

Overview and use of R.E.M. GPIO pins and Power Rails

The Renix Engine Monitor is Open Source and Mod friendly so this makes them very customizable for the power user. One of their exciting features is the Extra In/Out Support that is built into some models and is made easy to access. If you know a thing or two about Arduinos or other microcontroller, then you know that free pins are awesome for custom stuff!

R.E.M. v1 Alpha
The R.E.M. v1 is a little tricky to mod as nothing was easily broken out. The unused Regulator Footprint can serve as a basic power rail though. The Pro Trinket doesn’t have a serial converter chip built in(FTDI header though) but it does have some bonus nachos with 2 extra AnalogRead ONLY pins on A6 and A7.

Check out the Adafruit Pro Trinket 5v for full stats

  • Free GPIO Pins
    – Digital: 1 (TX), 13 (LED)
    – Analog: A3, A4, A5, A6, A7
    (Note A3 was later reserved for AW-4 RX)
    (Note A6 and A7 are AnalogRead ONLY)
  • Jack Pins
    – Board must be removed from case and leads soldered onto pins with fine tip soldering iron.
  • Power Rails
    – REG1 Left pin: 5v from Arduino
    – REG1 Middle pin: 12v from vehicle ignition (after Diode)
    – REG1 Right pin: Ground

R.E.M. v2 Beta
The R.E.M. v2 is the first version with basic mod support in mind. The 4 free Jack pins have been broken out and there are also dedicated power rails. The Pro Trinket doesn’t have a serial converter chip built in(FTDI header though) but it does have some bonus nachos with 2 extra AnalogRead ONLY pins on A6 and A7.

A Diode and Voltage Divider were included to read the Oxygen Sensor Heater Relay voltage but if you were so inclined, you could use it to read in a different circuit if needed (57.8k/10k safe to 34v).

Check out the Adafruit Pro Trinket 5v for full stats

  • Free GPIO Pins
    – Digital: 1 (TX), 13 (LED)
    – Analog: A3, A5, A6, A7
    (Note A3 was later reserved for AW-4 RX)
    (Note A6 and A7 are AnalogRead ONLY)
  • Jack Pins
    – E1, E3, E5, E7 broken out
    (Note E1 was later reserved for AW-4 RX)
  • Power Rails
    – BATT +: 12v from vehicle ignition (after Diode)
    – 5V: 5v from Arduino
    – GND: Ground

R.E.M.+ v3
The R.E.M.+ v3 is pretty packed but there is still a little play room inside. The i2c lines have been freed for the RTC clock but could also support other devices. The 3 free Jack pins also have a header in the Adapter as well.

Check out the Adafruit Metro Mini for full stats.

  • Free GPIO Pins
    – Digital: 1 (TX), 13 (LED)
    – Analog: A3
  • Jack Pins
    – E3, E5, E7 broken out
  • Power Rails
    – 12V: 12v from vehicle ignition (after Diode and 250mA PTC Fuse)
    – 5V: 5v from Arduino
    – GND: Ground

R.E.M.+ v3.1 Clock
The R.E.M.+ v3.1 is near identical to the v3 but there were also 0805 SMD pads added for an extra voltage divider circuit. Soldering the 2 Jumpers will connect Pin A3 to E3 through the Vdiv.

Check out the Adafruit Metro Mini for full stats.

  • Free GPIO Pins
    – Digital: 1 (TX), 13 (LED)
    – Analog: A3
    (Note A3 has jumpers and pads for an optional voltage divider)
  • Pads
    – R OIL: R1 of optional VDiv
    – R OIL G: R2 of optional VDiv
  • Jumpers
    – O JS: Voltage Divider to E3
    – O SJ2: A3 to Voltage Divider
  • Jack Pins
    – E3, E5, E7 broken out
  • Power Rails
    -12V: 12v from vehicle ignition (after Diode and 400mA PTC Fuse)
    – 5V: 5v from Arduino
    – GND: Ground

R.E.M. II v4
The R.E.M. II v4 opens up lots of modding capabilities with use of the new Teensy 3.2 platform. Lots of pins, program space, and speed means lots of interesting features and ideas can be added. Teensy 3.2 also has lots of bonus GPIO Pads UNDER the pcb but they are NOT accessible once the unit is assembled.

Check out the PJRC Teensy 3.2 for full stats.

  • Free GPIO Pins
    – Digital: (7, 8 *), (10, 11, 12, 13 **)
    – Analog: A3, A10, A11, A14
    – DAC: A14
    (*if Bluetooth isn’t used)
    (**if MicroSD Slot isn’t used)
    (A3 has optional Vdiv up to 18.5v)
    (A10 and A11 are AnalogRead ONLY)
  • Jumpers
    – JA3D: A3 to E3
    – JA3A x2: A3 to E3 through 18.5v Voltage Divider
    – JA10: A10 to E5
    – JA11: A11 to E7
  • Jack Pins
    – E3, E5, E7 broken out
  • Power Rails
    -12V: 12v from vehicle ignition (after Diode and 350mA PTC Fuse)
    – 5V: 5v from External Regulator (up to 500mA)
    – 3V3: 3.3v from Teensy
    – GND: Ground
  • Other
    – BlueTooth: for Bluetooth Module (5v, gnd, tx, rx)
    – Gyroscope: for Gyroscope Module (5v, x, gnd, scl, sda)
    – MicroSD: wrong footprint for intended socket (spi and power)

R.E.M. II v4.1 Standard and Clock
The R.E.M. II v4.1 is similar to v4 but pins were re-arranged for better use. Extra Voltage Dividers have been added as well as an Op-Amp which works with the DAC pin for signal out use. Teensy 3.2 also has lots of bonus GPIO Pads UNDER the pcb but they are NOT accessible once the unit is assembled.

Check out the PJRC Teensy 3.2 for full stats.

  • Free GPIO Pins
    – Digital: (9, 10 *), (8, 11, 12, 13 **)
    – Analog: A1, A2, A3, A14
    – DAC: A14
    (*if Bluetooth isn’t used)
    (**if MicroSD Slot isn’t used)
    (A1 has optional Vdiv up to 18.5v)
    (A2 and A3 have optional Vdiv up to 5.5v)
    (A14 has op-amp for up to 5.5v out)
  • Jumpers
    – A1: A1 to E3
    – A2: A2 to E5
    – A3: A3 to E7
    – 12v1 x2: A1 to E3 through 18.5v Vdiv
    – 5v2 x2: A2 to E5 through 5.5v Vdiv
    – 5v3 x2: A3 to E7 through 5.5v Vdiv
    – SGNL OUT: A14 to E5 through Op-Amp
  • Jack Pins
    – E3, E5, E7 broken out
  • Power Rails
    -12V: 12v from vehicle ignition (after Diode and 350mA PTC Fuse)
    – 5V: 5v from External Regulator (up to 500mA)
    – 3V3: 3.3v from Teensy
    – GND: Ground
  • Other
    – BlueTooth: for Bluetooth Module (5v, gnd, tx, rx)
    – Gyroscope: for Gyroscope Module (5v, x, gnd, scl, sda)

R.E.M. II+ v5.2 Standard
The R.E.M. II+ V5.2 is a massive jump from V4 since it uses a fully embedded chip design and gives us access to near double the amount of pin compared to the previous version. I have tried to better organize them into groups shown below.

REM Adapter In/Out Port:
In/Out Port 1 UP: 18v analog input for voltage measurements. (DMM Volts)
In/Out Port 1 DOWN: Relay Driver Ch1 for fan or other device control, 400mA Poly Fused

In/Out Port 2 UP: 5v analog input for analog output devices.
In/Out Port 2 DOWN: Relay Driver Ch2 for fan or other device control, 400mA Poly Fused

In/Out Port 3 UP: Resistance sensing circuit up to 100kΩ (DMM Ohms/Resistance)
In/Out Port 3 DOWN: Relay Driver Ch3 for fan or other device control, 400mA Poly Fused

In/Out Port 4 UP: 18v analog input, connected to o2 Heater Relay Circuit in Adapter*
In/Out Port 4 DOWN: 5v analog output for piggyback signal tuning (DMM Signal)

* A solder bridge in the adapter needs to be removed to disconnect the o2 pin so be careful! On DMM Adapters the o2 pin is automatically disconnected when the DMM Switch is in the “Signal” position.

REM Bonus Mod Jack:
The Bonus Mod Jack opens up even more free pins for easy access inside the vehicle. These pins do not have as many protection features as the In/Out Port, so be careful with 12v systems!

Mod Pin 1: Regulated 5v Rail, Poly fused at 120mA.
Mod Pin 2: Relay Driver Ch4, load capability is half of other channels
Mod Pin 3: Unconnected, left open for custom modding requirements
Mod Pin 4 & 5: 5v Analog Inputs for analog output devices (Port 5 & 6)
Mod Pin 6: REM Ground Power Rail, connects to vehicle ground through adapter

Other Stuff:
Vias:
– 26 / A15
– AG: Analog Ground
– A10
– A11
– TX1: Digital Pin 1, TX1
– TXC: Digital Pin 3, TX Can Bus
– RXC: Digital Pin 4, RX Can Bus
– 3B+: unused diode to 3v linear regulator. MAX 6V
– Sig: Output from Op Amp piggyback signal generator
– B+ unused diode to 5v switching regulator. MAX 24V
– EN: Enable to 5v switching regulator, active low.
Jumpers:
– J2: Jumps Signal Out to Port 2 to avoid messing with o2 relay circuit
– J3: Jumps Port 3 functions to the Port 3 Output. Cut trace to allow custom use.