Another test:
Conditions:
I am running the RX+ off the same 7809 linear regulator, but now with a 12V lead acid battery instead of the cheap 12V switched mode PSU I had been using up till now for both TX and RX+. On the 7809, I've got a 0.1uF ceramic capacitor on the input side (12V lead acid battery), and 22uF electrolytic on the output regulated 9V side, each on the breadboard, about 9cm of wire from the TO220 package of the 7809 - perhaps not close enough?. The 7809 has a small heatsink, so should cope with 1A draw.
Timeout to big clock display set in software config to 1 minute.
Observations:
- 3.3V reg on the RX+ gets hot as the system starts up, and hot with the main weather summary screen showing all the sensor readings at once.
- When the big clock screen kicks in, the 3.3V reg cools down so it's just a bit warm to the touch even though the TFT is on (this was a surprise to me!)
- Press the push button PB1, back to the summary screen, and the 3.3V regs gets HOT
Mysterious...
Buck step-down regulator should arrive tomorrow, to test as 9V supply for RX+ instead of the 7809 breadboard hack that I've been using up till now. Hope I'll have time to try it
Conditions:
I am running the RX+ off the same 7809 linear regulator, but now with a 12V lead acid battery instead of the cheap 12V switched mode PSU I had been using up till now for both TX and RX+. On the 7809, I've got a 0.1uF ceramic capacitor on the input side (12V lead acid battery), and 22uF electrolytic on the output regulated 9V side, each on the breadboard, about 9cm of wire from the TO220 package of the 7809 - perhaps not close enough?. The 7809 has a small heatsink, so should cope with 1A draw.
Timeout to big clock display set in software config to 1 minute.
Observations:
- 3.3V reg on the RX+ gets hot as the system starts up, and hot with the main weather summary screen showing all the sensor readings at once.
- When the big clock screen kicks in, the 3.3V reg cools down so it's just a bit warm to the touch even though the TFT is on (this was a surprise to me!)
- Press the push button PB1, back to the summary screen, and the 3.3V regs gets HOT
Mysterious...
Buck step-down regulator should arrive tomorrow, to test as 9V supply for RX+ instead of the 7809 breadboard hack that I've been using up till now. Hope I'll have time to try it