DSD TECH HM-19 Bluetooth 5.0 BLE Module with CC2640R2F Compatible for DIY

had a problem with the BT device after a week where it would just go unresponsive. I contacted customer service and they apologized for my troubles and immediately sent a replacement which works fine. Friendly and responsive, just what I want for customer support.

Setup was super easy with the included instructions. Hooked it up to an Arduino Leonardo, copied a simple example off the Internet, downloaded the iOS app, and everything worked great. I was able to turn an LED on and off remotely using my iPhone 10XS.

First, the device cannot enter AT mode. There's a footprint for a push button but I tried shorting the pads and no dice. The board has an EN pin but the device does not enter AT mode when shorting it with the supply pin on boot.Second, in normal mode the DSD APP sees garbage characters when sending AT commands from my PC and the PC sees garbage characters when sending them from the DSD APP. This is a tell tale of the baud rate not being set properly but I tried with all possible baud rates and tera-term settings to no avail. Do not waste your money on this POS!!!

Connected this module to my Arduino and was able to communicate without issue. Having separate BLE characteristics for read and write was a nice touch over other modules I've used. The transmission buffering/bandwidth seems to much better than the DSD SH-11.

I was able to pair it with my android 10 device and able to send commands to it using the dsd tech app. Seems to have a really good signal. Looking forward to building with these modules!

speedy deliver, product as described

I had low hopes for this low cost device. Unfortunately, even though my expectations were low, they still were not met.The datasheet claims 100m range in open spaces. I can get about 3-5m (~10-15ft) depending on which direction I walk even with a totally unobstructed view.Once a connection is lost, it's anyone's guess what will happen next. Sometimes it repairs no problem. Sometimes Slave and Master both stay blinking no matter how close you get. Sometimes, Slave will go solid and Master will turn off its LED but the connection remains. Sometimes, Slave will blink and Master led will turn off. Sometimes, Slave will go solid and Master will Blink. Whenever any of the above happen, whichever one (Slave/Master/Both) is the culprit needs a total power cycle (removing tx/rx too bc they provide enough phantom power for the units to not reset)In summary, 100m is more like 3m and connection stability ... what connection stability?

Fast