Howard's original comment: - - - This hand controller with OLED display plugs into OnStep's ST4 port and is able to fully operate an OnStep (Alpha branch) telescope controller. The ESP32S micro-controller onboard runs the smart hand controller firmware (from OnStep's /src/addons/St4Serial directory.) On earlier versions there was a problem with the display connection on the PCB but this should be fixed. Still be careful to verify the schematic and PCB and your exact display to be sure the connections are correct. - - - This version is a respin of a design that has had many builds. It is worth describing why I have done this redesign. I like having a longer tether on my hand controller, and the original designs have been limited to a 3 or 4 foot cable length because over that the communications become unreliable. That has been traced to the voltage drop that happens over the longer (I use 10 feet) coiled cables. In order to combat this, I have added level shifters at both the OnStep controller and the SHC itself, turning the voltage over the cable up to 5V and stepping it back down to 3.3V at both the SHC for the ESP32S and the OnStep controller (which in my case uses a S6 board with a customer daughtercard). This SHC design also includes a 5V to 5V regulator and a 5V to 3.3V regulator. Those provide the controlled voltages required to make certain that the communications are solid between the devices. I had been using a Teensy 3.2 based SHC for some time. Because of the limited memory that device supports, I decided to switch to the ESP based device. The other designs for this ESP SHC had a slightly different footprint, and I already had 3D printed several cases and did not want to start over on that, so I used the footprint from the Teensy SHC to design this board. v2.01jp - converted the Teensy footprint design to use a ESP32S VROOM module after extended conversations with Howard (the designer of the OnStep and the original Teensy based SHC). Removed the mounting holes for the smaller displays (I am using the 2.4" for all my SHCs... Sorry if this is a problem for you but as you age you will thank me!) The mounting holes for this board line up with the previous Teensy boards, it might not line up with earlier ESP boards designed by other people. v2.02jp - This version adds a 5-way switch in place of the center shift button. There are also some other minor part movements. v2.03jp - Added a step up converter for the 5V power supply to correct a problem that the ESP chip is extremely sensitive to low voltages. Testing comments: I have built and tested this version, it appears to work fine.