So it sounds like we already have a scale we like. Maybe it could be a jumping off point?
(probably want to acquire a throw away version first, rather than dismantling the one we have) Converting scale readout to log as well as display The upgrade to bluetooth for logging
Granted this is done on a bathroom scale, but the LED readout is likely remarkably similar. I’ll bet some of the electronics folks already posses this type of knowledge.
I’m not sure it’d come in much cheaper than the conversion module reference by Able, but you could use the Pi as the processor, perhaps, combining costs for getting the info out of the scale as well as doing whatever we like with it after.
I think @Kentamanos comments about @Brandon_Green original kiosk application have a great deal of relevance here. In part that was why I was pointing out the cost of scales that would accomplish what is needed here.
Your idea about modifying the scale to provide a readout is certainly one way to address the problem, but has the potential to be even more costly then simply purchasing a scale with the readout. Particularly when the scale breaks eventually and a replacement needs to be reverse engineered to provide the same readout (or re-write the code to read a new format).
I propose to follow the spirit of Brandon’s original application for the kitchen and provide a single piece of functionality. The ability to have a local database of rfid numbers with balances. That will allow people to track how much they have payed and how much they have used. I don’t think attempts to incorporate the scale or even worse the queuing system are likely to do anything but prevent the project from ever being finished.
I have a rfid reader being delivered today, and already have several pi touch screens I can use to put something together. The hardest part (at least for me) will be designing a case to house the electronics.
I can help design the casing. This would be a great addition to 3D fab, we appreciate the help.
Not to feature-creep the issue, but I’m thinking if we could even pull data from Octoprint itself of filament usage, time/date, RFID logging. But it’s good to start simple first like you said.
I am going to stick to the basics, and we can talk about improvements after we have a working prototype.
I will take you up on the case as soon as I finalize the components and how they need to be wired I’ll give you the info and you can produce the case while I finish the code.
The rfid reader I received today will not work, so I have had to order a different one that I should receive next week.
by the way, if you missed it here is the current layout concept I have for this