How to build your own Daystate GCU v5 programming tool, this is the GCU found in the Red Wolf. The GCU communicates with the Daystate programmer via a '1 wire' serial interface, to build one of your own you will need the following components:
1 x 4k7 1/4 Watt 5% resistor (EBay $3.49 for 100)
1 x 1N4148 Diode (EBay $1.59 for 10)
1 x JST SH 1.0 5 pin plug with tails (EBay $3.49 for 10)
1 x USB-UART 5V TTL adapter (EBay $2.58 each)
All these parts can be found easily on EBay or Amazon although you may end up buying a pack of 10 or a 100 diodes and resistors. Even if you don't have any of these parts on hand you can still build the hardware for less than $20
Once you have these parts you will need to assemble them as shown in the schematic diagram below
View attachment 193719 Note the pin number on the programming header of the GCU
View attachment 193734 Depending on the type of USB-UART adapter you purchased you may be able to add the diode and resistor directly to the adapter
View attachment 193741 A fully assembled adapter and cable look like this (only 3 of the 5 pins are required)
View attachment 193747 Now that you have your hardware assembled you can plug it into your PC and follow the vendor's instructions to install drivers etc. Next you will need to download some software from Github.
https://github.com/DaystateRebel/gcui The gcui tool is written in Rust (
https://www.rust-lang.org/tools/install) but for convenience I have made a compiled Windows binary available here:
https://github.com/DaystateRebel/gcui_binaries/blob/main/gcui.exe Download the exe (or build from source code if you prefer) and put it in a directory on your hard drive. Open a command prompt ad "cd" to the directory where you saved the executable. Gcui can perform the following functions (replace comX with the name of the USB-UART hardware, you'll find it in Device Manager)
To read power settings from the GCU
$ gcui.exe --port=comX --read --filename=file.csv
To write power settings to the GCU
$ gcui.exe --port=comX --write --filename=file.csv
To read the current air pressure from the GCU
$ gcui.exe --port=comX --pressure
To read the current pulse duration from the GCU
$ gcui.exe --port=comX --pulse
To read the GCU version
$ gcui.exe --port=comX --rwversion
The power settings are read to / written from a .csv which you can open in Excel/Google Sheets
View attachment 193776 Congratulations, you can now easily download, edit, save and reload power settings from your computer instead of writing them on bits of paper - welcome to the 21st Century!
Coming next - What do all these numbers mean and how do I recalculate HS & LS? I will also be adding support for "locked power" mode to gcui so we a full featured alternative to the current hardware programmer
Happy Hacking
Rebel
. My Son who’s the expert is busy with his new born Son so Il have to wait a while.
