What I've done in another project is use a cheap 1200mA/hour power bank from a local pound shop (dollar store?) This has a usb 5v output via a buck convertor. A problem with this is that you can't charge it while it is in use. To solve that I took the PCB from a second similar power bank and connected it to the first battery. This works well. I can use the device and top it up with a USB charger at any time whether it is in use or not and without having to remove the battery.
I followed your amazon link, and it led me to this: https://www.amazon.com/gp/product/B07TK845JF/ref=ox_sc_act_image_1?smid=A2U7URO3I3000U&psc=1 2 650mAh 7.4V batteries and 2 charging cables for $24! Some quick measurements I made on my throttle show that it draws under 100mA, so realistically I can expect at least 4 hours per charge. And they should fit nicely in the case. By the way, I noticed on your website that you are running JMRI on a RPi. So am I, although I am just learning how to use JMRI. So far the throttle only works when I communicate directly with the DCC++ Arduino; If I run JMRI the throttle doesn't work. Also, thanks for the offer for a case; I may just take you up on it when I am ready.
That looks like a good choice. I saved the link, thanks. Interesting. I'm using JMRI mainly to program decoders and to run Engine Driver as a wireless throttle. I'm getting use to the phone as a throttle but I'd prefer to have buttons, knobs and switches in my hand, thus the desire to build the throttles. I guess I could deal with using either one or the other at a time but it would be nice if that could be resolved. I live in a remote area so chances are there won't ever be anyone else on the layout at the same time that I am except maybe a friend or the wife so having two throttles would work for me. Maybe the DCC++ guys doing all the good work now with DCC++ could look into why they won't work at the same time. If you come up with something that resolves it please report back. Sumner
Update: I wonder if the problem is that when the throttle and JMRI are running at the same time they are competing on the same serial port? I don't have enough knowledge to go further than that, https://www.trainboard.com/highball/index.php?threads/dave-bodnar-wired-throttle-problems.127105/ Sumner
If the problem with trying to run JMRI and Dave's throttle at the same time is that they are both on the Arduino's Uno's only serial port would the following possibly overcome that by assigning a second software serial port to one of the free pins (if there is one)? https://www.arduino.cc/en/Reference/softwareSerial Sumner
I run DCC++ with JMRI running on a RaspberryPi3b+. I have built the Dave Bodnar wireless throttle to go with it. I can run my phone as a WI-FI throttle and run my Bodnar wireless throttle at the same time with no issues. If you are running the wired throttle it should be running on the Transmit and Receive pins on the Uno and Nano. Later Richard
In order for the most compatibility, you could write to the WiThrottle interface. We are getting close to having built-in capability in DCC++ EX to support engine driver directly. If you want a physical throttle instead of your phone, just write WiThrottle commands.
