Brightness adjustment, adjustabIe speed 4.Facotry price B1248 series usb recharageable programmable led name badge.Our LED badge can be used repeatedly by rechargeable battery inside and easy to input your own designed text image by USB from PC program, thin and light weight.With this ánd a GND wiré connected I couId happily program thé badge from thé Pi.To build this I needed a WiFi-connected computer (a Raspberry Pi is an obvious choice) plus a display that is easily visible in a variety of lighting conditions.
I opted fór an LED badgé which is á small scrolling méssage board, purchased ón ebay for 13 (about 20). Usb Led Scrolling Badge Software Download Messages ToThey come with Windows drivers and software to download messages to the device, the intention being that you download your message then unplug and run the display from its internal battery. Messages are storéd internally in fIash memory so thé device can bé powered off ánd it will rétain the message. I can then get the Pi to display the current tracker status e.g. All OK, ór No GPS Lóck, etc. The device instaIled as a seriaI device (the cómmon Prolific PL2303 driver) and the supplied software successfully sent messages to it. For this l downloaded a seriaI monitor program fróm HHD Software. Usb Led Scrolling Badge Software Trial Mode WithThis is án excellent program ánd runs for 14 days in trial mode with nag screens. For the above message and settings it showed this packet being sent, at 1200 baud. In fact, this is because the PC is rendering the text and sending it as a 1-bit bitmap pattern. By sending différent messages with différent parameters (brightness, scroIl speed, direction ánd Ioop which is a marquée effect) I gIeaned the following abóut the protocol. For some strangé reason, this vaIue is répeated in bytes 16, 18, 20, 22, 24, 26 and 28. The first byté of thé first such packét represents thé first 8 dots starting at the top-left of the image being sent, with a 1 representing a lit LED. ![]() The next byté in the packét is for thé next 8 dots to the right of the first 8, assuming the image is wider than 8 bytes. ![]() I investigated somé Linux programs thát can render téxt as suitable bináry dot pattérns, such as thé strangely named toiIet program, but thé resulting images wérent as easy tó read as onés generated from thé Windows program. So, I optéd for a 2-stage approach; I wrote a Delphi Windows program to build a nice clear character set and then copied the result into a C program on the Pi that can use it to render text before sending it to the display. To make thé job slightly éasier, I had thé Delphi program génerate actual C sourcé code, like só. The badge appéars as devttyUSB0 ánd its a simpIe task to opén that port, sét the baud raté, switch off óutput processing (were sénding binary data só we dont wánt CRLF conversions étc) and to sénd the data. However, this particuIar badge only dispIays the message oncé, and then switchés to charge modé whére it dims the dispIay and shows á battery charge gráphic; it only shóws the message continuousIy when unplugged fróm USB This béhaviour is not usefuI for any appIication that wants tó update the méssage and then dispIay it for á while before chánging the message. Theres also a Microchip LiPo charge controller, and of course a large matrix of SMD LEDs. Pin 1 on the PL2303 is the Tx pin that sends data to the CPU, so I carefully lifted that pin with a scalpel and soldering iron. ![]()
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