Changes from Rev 1.0:

• Increased solder pads for restart button for easier soldering
• Moved C3 down slightly to allow more room for Pololu regulator
• Moved buzzer down slightly
• Altered/added text labels

This is hat-like board for the EasyRaceLapTimer system’s Raspberry Pi powered base station. This was designed to make cable setup easier, as well as provide an alternate means of powering the system, using a cheap regulator and hobby grade lipo/li-ion/SLA (2-3S) batteries. The board is sized for both the Raspberry Pi Model 2/3, for base station use, and Raspberry Pi Zero/A+/B+, for satellite station use (gate penalty enforcement - not tested).

Parts to complete base station:

• Raspberry Pi Model 2 or 3
• USB WiFi Adapter (not needed with Pi 3, but WILL have better range)
• 2.54mm 2x20 Pin Double Row Female Pin Header
• 5V regulator to power Raspberry Pi
  • Mini 360 DC Step Down Regulator (set to 5V BEFORE connecting to Pi)
  • Pololu 5V, 1A Step-Down Voltage Regulator D24V10F5 - also available here and here
  • A UBEC might also work, but be certain it outputs 5-5.1v, and can supply 2amps. Some UBECs output 5.5-6v which will destroy the Pi.
• 3x TSOP 31238 IR Receiver
• 2x MMBT2222A (T1, T2) <== Also used on Transponder SMD R1.4
• 2x 1kOhm 1206 Resistor (R2, R3)
• 100Ohm 1206 Resistor (R1) <== Also used on Transponder SMD R1.4
• 2x 10uF 1206 Capacitor (C1, C2) <== Also used on Transponder SMD R1.4
• 330-470uF Capacitor (C3)
• SMD Tact Switch 3x6x2.5mm <== Also used on Transponder SMD R1.4
• 5v Buzzer
• Wiring to connect IR receivers
  • 26 AWG servo wire for IR receivers
  • Crimpable servo connectors for IR receivers
• Power lead of choice
• Battery of choice (I use a 12v 8Ah sealed lead acid battery which also powers a speaker system, but a 2s lipo, li-ion, etc will work if you are just looking to power the Pi)

Optional:

• Case to house Pi and hat
  • 3D printable case - top and bottom
• 3D printable mounts for IR receivers
• 2.54mm single row male pin header (only 4-6 pins are needed)
  • Momentary Push Button Switch Panel Mount - Arcade Button, maybe
  • 12v External Buzzer
• Real-Time Clock to maintain time across boots (requires hand wiring)

Parts to create a bad ass sound system for playing the sound effects:

• .50 cal ammo can
• 20Wx2 stereo amplifier
  • 2.1mm by 5.5mm DC barrel connector - if you don’t want to cannibalize the power cord that comes with the amp.
• 4 inch speakers
• 3 foot 3.5mm male to male stereo cable
• 12V 8Ah sealed lead acid battery
• USB WiFi Adapter with External Antenna
  • 20cm RG316 RP-SMA Extension - for mounting antenna on top of ammo box
• Screws and nuts for mounting speakers and amp
• Velcro for mounting Raspberry Pi and battery
• Misc wiring

For more informaiton visit:

• EasyRaceLapTimer.com
• RCGroups.com thread
• Facebook Group

ERLT IR transponders for aircraft