@gohan between positive end of one of the two aa batteries and where it enters circuit. If I start off by having battery connected, the release it slowly with the multimeter attached and without breaking circuit I get my 6ua. However after the timer runs out and the radio comes back on I'm stuck at 1ma. The radio at that point doesn't want to work and it doesn't return to 6ua
@sundberg84 @gohan. Apologies , that's a typo on my part. It jumps to 1ma do 60ms from 6ua. Which I'm happy with I think. My question was more how I can measure it properly. The multimeter seems to be effecting the circuit.
@sundberg84 Thanks Sunberg, pretty much sorted now. It was the sensor, i changed libraries and it solved my problem. In theory i was using the forced read with both, but only the sparkfun bme280 library worked in reducing the power. To the best of my knowledge, i'm now running at 6ua most of the time with a 60ms (i timed from beginning to end of the loop method) jump to 1amp every three minutes to get a reading. It's difficult for me to capture the amps properly as when i put my uni-t digital multimeter into the circuit, the nrf stops working. Any thoughts on why that might be?
@sundberg84 To give you an update. I've changed from a dht22 sensor to a bme280 i2c sensor. The sensor is running off a4 and 5 and power is gotten directory from 2aa batteries. My original problem is gone in that it's working fine as a mysensors node. My issue though is when in sleep mode, i'm running at 1ma, when i would expect to be down in the low ua area. Any thoughts? The code i'm using is based off of this thread: https://forum.mysensors.org/topic/3816/bme280-temp-humidity-pressure-sensor/5
@sundberg84 I'll also take a look at your pcb. I was trying to achieve a pcb like that. A generic one to use with various sensors. I Was hoping to do it myself for the sake of learning. But I may have change tact.
I've actually ordered some bme280s which I'm waiting on, I think they will work down to low voltages too. So hopefully that will sort this issue by not needing the step up.
I would like to still to be able to figure out this problem though. I tried removing the dht22 completely to see if it was contributing to the problem, no luck. I've tried various capacitors over the ground and vout to no avail.
How would I go about analysing noise on the circuit?
Thats for the response guys. So tried connecting directly to the battery. I cut the trace on the pcb, then soldered a wire directly from the vIn to the positive leg of the 4.7u cap that leads to the radio. No joy though. Still same problem.
To the point about disabling bod, i have done that already, my issue with that setup though is that my dht22 seems to give inconsistent measurements when operating. It would give readings a degree apart every 5 minutes when the temperature would have remained a lot more stable. I assumed this to be due to the 2x batteries running at just a tad below 3v, while the dht22 is rated at 3.3v. Hence i thought the stepup would fix this problem.
@sundberg84 Ok, thanks guys. I'll try your suggestions out tonight. I would have preferred to do it through the step up to get the most out of the batteries but maybe this is not practical.
Any thoughts on what I could do to fix the issue permanently without the multimeter?
I made progress. So the capacitor idea doesn't seem to work. However rozpruwacz suggested measuring the current which I did. I disconnected the negative wire and put my multimeter in between the negative from the battery and the ground pin on the step up module. I measured 72ma when the device powers up, then it runs at .16ma when in sleep mode. But here is the thing, in this configuration, mysensors worked as a thermometer. I got humidity and temperature readings from the sensor to my mqtt server through the gateway over the nrfs. When I removed the multimeter again from the equation it stopped working. Surely this would hint at what the problem is for someone more familiar with electronics than myself?
The NRF is a NRF24L01+ without the antenna on the gateeway and all of the sensors. I'm going to try the capacitor idea now. I'll try measuring current shortly too.
@rozpruwacz Both resistors are 10k. I can measure the amps, i'll do this tonight and get back to you. thanks again
@rozpruwacz Ya, it's a module and it's the 3.3v step up module recommended on this page. Thanks for your help by the way
@FatBeard I should point out that the step up was an afterthought and it was the ground and vout of the stepup were connected directly to the power rail along the bottom. It powers the whole circuit.
Here is my breadboard design, i'm afraid the schematic in fritzing isn't really in a state to post here. It's unreadable. The resistors shown in the diagram wouldn't have the correct values i used. The values i used are from the arduino site for creating an arduino. The ones shown are used for the sake of creating a pcb. The DHT22 goes on the 4 pin header, the NRF goes on the 8 pin header.
Hi, i've got a barebones arduino circuit set up with a dht22 sensor. It's powered off 2 aa batteries. All works well with the two batteries even when they are running at about 3.0 volts combined (it would probably run at lower voltages but batteries haven't gone down that far yet). If i power directly from usb with my ftdi interface all works. However, when i add the 3.3v step up, the radio doesn't get a response from the nrf gateway anymore. I have a 4.7u capacitor on the nrf. The gateway is receiving some data but not all as i can see "mygateway1-out/0/255/0/0/18 2.1.1" in my mqtt broker every couple of seconds but the mysensors client never seems to get fully initialised. I've tried two or three of the step ups and checked the voltage with a multimeter and i'm getting circa 3.3v. One thing i did notice is that when i swapped in one of my 3 dht22's it worked initially but then stopped, the other two wouldn't (all work without the step up). I think this is a bit of a red herring but putting in here for information. Any thoughts?
