thanks CGR !
DIY DIY EC Meter
- Thread starter donkeykong
- Start date
some more progress on the box to report!
I've made a few changes and added a few things to the system. Firstly I rerouted power from the new power supply arrangement. It now powers the Arduino and LCD rather than power being drawn from the USB port. Also means it can now be standalone, not require a USB host to operate.
Other than that a few additions, a humidity sensor has been attached, as well as an NTC which will both go in the grow chamber. And I added a RESET switch, to enable to cold start the system easily from outside the box.
I've got the SW together to read those new sensors and its pulling up the readings onto the LCD.
Need to do some software smoothing to make the readings more stable, but they are pretty decent as is.
I've made a few changes and added a few things to the system. Firstly I rerouted power from the new power supply arrangement. It now powers the Arduino and LCD rather than power being drawn from the USB port. Also means it can now be standalone, not require a USB host to operate.
Other than that a few additions, a humidity sensor has been attached, as well as an NTC which will both go in the grow chamber. And I added a RESET switch, to enable to cold start the system easily from outside the box.
I've got the SW together to read those new sensors and its pulling up the readings onto the LCD.
Need to do some software smoothing to make the readings more stable, but they are pretty decent as is.
Just modified the code to average the readings its giving from the Arduino's ADC readings. The thermistor and humidity sensor are now on the end of a long shielded cable, so they could be put into a grow chamber/tent. I used 6-way mini-DIN connector to get the signals into the box. With the averaging the readings are now very stable. I make the read 100 times then find the average, don't know if its overkill without experimenting, but its sorted it
Now the readings are adding up well ;
There are two temp sensors at the moment, the one on the PCB itself which is a pre calibrated TMP100 digital IC , and the one on the end of the probe, which is a thermistor. Now if I put these two close together and allow to settle they give exactly the same reading. Also the humidity after a small tweak is showing the same readings as a maplins weather monitoring kit.
Have not had a chance to get the real time clock (RTC) tested yet, probably that will be next.
Definitely want to be able to log the data, and find a good way to get it out and visualise it. There is an SD card installed of 2GB, but I don't want to have to keep pulling that in and out, ill leave that for local storage. Last thoughts were whether a raspberry pi could make a happy job of a webserver, collecting and displaying the data the arduino generates. Arduino is good since its OS'less, just runs and should be reliable. The Raspberry Pi has other qualities, with running OS and able to do a lot more - HDMI out, for example
hey guys.... been busy doing little bits towards the project as usual.
over the weekend I fitted a couple more DIN connectors on the back for sensor probes, got the real-time clock up and running and sorted out the motherboard / riser card strategy!
first off I got the RTC up and set correctly, now reads in to the application fine, so I can display that info and later use it to do things with at specific times. Arduino has a timealarm library also which sounds like it could be useful later.
I also routed a few more signals around the pcb , which Im calling the motherboard from now. Then I put down some 16-way header sockets, just two lots for now, but more can be added if I need, simply soldering more connectors on without any extra wiring since the veroboard carries the signals across that area. On this "bus" I included access to all the power rails, +-5V , +-12V , as well as I2C bus , 4 analog inputs and 4 digital I/O
The idea with this is that it will be easy to prototype the sensor circuits and just slot the card into the top of the motherboard and attach the probes. The expansion cards will host the electronics to do the EC, pH, etc etc .
Also makes quite good use of the box volume like this.... I still have the other half spare
The two cards mounted on there for now are "blank" , ready for mounting with some components.
over the weekend I fitted a couple more DIN connectors on the back for sensor probes, got the real-time clock up and running and sorted out the motherboard / riser card strategy!
first off I got the RTC up and set correctly, now reads in to the application fine, so I can display that info and later use it to do things with at specific times. Arduino has a timealarm library also which sounds like it could be useful later.
I also routed a few more signals around the pcb , which Im calling the motherboard from now. Then I put down some 16-way header sockets, just two lots for now, but more can be added if I need, simply soldering more connectors on without any extra wiring since the veroboard carries the signals across that area. On this "bus" I included access to all the power rails, +-5V , +-12V , as well as I2C bus , 4 analog inputs and 4 digital I/O
The idea with this is that it will be easy to prototype the sensor circuits and just slot the card into the top of the motherboard and attach the probes. The expansion cards will host the electronics to do the EC, pH, etc etc .
Also makes quite good use of the box volume like this.... I still have the other half spare
The two cards mounted on there for now are "blank" , ready for mounting with some components.
Nice project you have going on.
The arduino can act As a simple webserver. No need for the pi. Live feed only i think.
Some Web sites Can log it for you. Live feed,stats,grapfs and e.t.c.
I Don't have a any links tho.
But i.ll tjeck up on it.
Aften Reading your thread. Might Think i Will make some similar. But mainly Reading ph. To High ph, relay switch. To feed deluted ph Water to my res.
But awsome project you have going on
Keep it up
Peace
The arduino can act As a simple webserver. No need for the pi. Live feed only i think.
Some Web sites Can log it for you. Live feed,stats,grapfs and e.t.c.
I Don't have a any links tho.
But i.ll tjeck up on it.
Aften Reading your thread. Might Think i Will make some similar. But mainly Reading ph. To High ph, relay switch. To feed deluted ph Water to my res.
But awsome project you have going on
Keep it up
Peace
thanks KsjAuto !
it will take a while to get it all together but I like having something to screw about with.
Yes I saw options for adding the Ethernet interface to the arduino directly but I hadn't made my mind up about that yet. Also I noted yes some online services that make it easy for arduino to post data, cant remember what it was called.
With this though, I don't think i'll rely on public services or store any data outside the immediate network, bit security conscious me. Remote access can be allowed, i'd vpn in to the network to see or change something.
Also I thought splitting roles could be a good thing, the arduino is going to end up very connected. On the I2C bus there will be a bunch of stuff, ADC's, RTC, IO expansion?, Temp sensors.... SPI already has the touch controller, a lot of digital IO chewed up by the LCD, SD card interface etc. I have to see if the Ethernet modules can coexist easily or not
let me know if you start up a project also , would be interesting to see, share some ideas.
it will take a while to get it all together but I like having something to screw about with.
Yes I saw options for adding the Ethernet interface to the arduino directly but I hadn't made my mind up about that yet. Also I noted yes some online services that make it easy for arduino to post data, cant remember what it was called.
With this though, I don't think i'll rely on public services or store any data outside the immediate network, bit security conscious me. Remote access can be allowed, i'd vpn in to the network to see or change something.
Also I thought splitting roles could be a good thing, the arduino is going to end up very connected. On the I2C bus there will be a bunch of stuff, ADC's, RTC, IO expansion?, Temp sensors.... SPI already has the touch controller, a lot of digital IO chewed up by the LCD, SD card interface etc. I have to see if the Ethernet modules can coexist easily or not
let me know if you start up a project also , would be interesting to see, share some ideas.
quick update since its been a few days. few things have been sorted more ....
First there has been a bit of a re-write with the software. Initially I was going with the libraries that sainsmart provide for the lcd, but these are based on work of Henning Karlsen and his UTFT library.
Switched to his latest releases and was able to progress much better, got the screen and touch working, loading bitmaps from SD card, displaying icons and making them buttons with the libraries on his page
http://henningkarlsen.com/electronics/library.php?id=52
So now the thing is looking better and better prepared for getting some buttons and functionality on there.
Also I rigged up the first sensor card, its EC meter based on the Arduino EC shield circuit, simple 555 timer based circuit. First thing to get up and running was the temp sensors on the ends of my EC probes. Four wires come off the EC probes, two are the conductors, and the other two are thermistor connection.
While I was setting that up I came to my next challenge, the Chinese probe, I don't have data for the NTC thermistor is contains, nor is it available for the RS components (lutron) probe. So I have to calibrate for them. You can see in the image the EC1 temp probe is quite different to what the air temp thermistor and the digital temp IC TMP100 are reporting. The probes in this case are all in the same location, so I want them to match.
now looking through the data sheet of the TMP100 , its got a high resolution, but the absolute accuracy can be +-1deg c.
Im going to spend a little time and try to get this right, the temp is a basic measure and affects a lot of other things, humidity, ec... so I want to calibrate all those temp sensors close to true value.
What I've done is decided to update the temp IC , to something more accurate. I selected the Measurement Specialities TSYS01, its quite an expensive part but has a 0.1deg c accuracy, and a very high 24bit resolution. Whats useful is it has stored calibration data, the application needs to read it first, then the ADC values and apply an algorithm to arrive at the temp to 0.1deg of true. I will mount this atop the unit I think.
The idea is that we can calibrate for the different probes by leaving them close to this accurate unit, and doing a slow temp cycle through the expected temp range, letting the arduino develop a calibration for each sensor.
The chip is pretty microscopic. 16 pin "QFN16" package. It was the only thing I could locate with this kind of absolute accuracy, and the only package I could get it in. So I have to work out how to mount it, this has led me down another adventure.
I've got a few bits on order for a mini project which should be very useful later. I ordered some adaptor PCB's (www.proto-advantage.com) which can adapt the QFN16 to an easy to work with DIP format. They will arrive next week sometime. Also I have a kit with solder paste, stencil for applying it etc...
To mount the thing on the board is the next challenge, and for that Im going to build me a reflow oven. I don't want to get too bogged down with that though so I found a tidy way to do it at a reasonable cost. I start with a Convection Toaster Oven, the tabletop kind, and convert it over with a kit put together by ES-Technical http://www.estechnical.co.uk/reflow-controllers/toaster-oven-reflow-conversion-kit
That conversion will allow it to solder SMT pcbs, handling proper temperature profile, ramp etc.
Its going to chew some time up to do that, then mount the chip (fingers crossed!) and then connect it (via 3.3v <> 5V level shifters) on I2C and start thinking how to read it since there is no ready built arduino library
But the reflow oven could be really useful later also, since I want to boil some of this stuff down onto proper PCB's I can have made. And it opens the doors to using parts that are beyond hand soldering.
this is the oven I will be converting : http://www.amazon.co.uk/exec/obidos/ASIN/B003SE88Z4/ref=ox_ya_os_product
First there has been a bit of a re-write with the software. Initially I was going with the libraries that sainsmart provide for the lcd, but these are based on work of Henning Karlsen and his UTFT library.
Switched to his latest releases and was able to progress much better, got the screen and touch working, loading bitmaps from SD card, displaying icons and making them buttons with the libraries on his page
http://henningkarlsen.com/electronics/library.php?id=52
So now the thing is looking better and better prepared for getting some buttons and functionality on there.
Also I rigged up the first sensor card, its EC meter based on the Arduino EC shield circuit, simple 555 timer based circuit. First thing to get up and running was the temp sensors on the ends of my EC probes. Four wires come off the EC probes, two are the conductors, and the other two are thermistor connection.
While I was setting that up I came to my next challenge, the Chinese probe, I don't have data for the NTC thermistor is contains, nor is it available for the RS components (lutron) probe. So I have to calibrate for them. You can see in the image the EC1 temp probe is quite different to what the air temp thermistor and the digital temp IC TMP100 are reporting. The probes in this case are all in the same location, so I want them to match.
now looking through the data sheet of the TMP100 , its got a high resolution, but the absolute accuracy can be +-1deg c.
Im going to spend a little time and try to get this right, the temp is a basic measure and affects a lot of other things, humidity, ec... so I want to calibrate all those temp sensors close to true value.
What I've done is decided to update the temp IC , to something more accurate. I selected the Measurement Specialities TSYS01, its quite an expensive part but has a 0.1deg c accuracy, and a very high 24bit resolution. Whats useful is it has stored calibration data, the application needs to read it first, then the ADC values and apply an algorithm to arrive at the temp to 0.1deg of true. I will mount this atop the unit I think.
The idea is that we can calibrate for the different probes by leaving them close to this accurate unit, and doing a slow temp cycle through the expected temp range, letting the arduino develop a calibration for each sensor.
The chip is pretty microscopic. 16 pin "QFN16" package. It was the only thing I could locate with this kind of absolute accuracy, and the only package I could get it in. So I have to work out how to mount it, this has led me down another adventure.
I've got a few bits on order for a mini project which should be very useful later. I ordered some adaptor PCB's (www.proto-advantage.com) which can adapt the QFN16 to an easy to work with DIP format. They will arrive next week sometime. Also I have a kit with solder paste, stencil for applying it etc...
To mount the thing on the board is the next challenge, and for that Im going to build me a reflow oven. I don't want to get too bogged down with that though so I found a tidy way to do it at a reasonable cost. I start with a Convection Toaster Oven, the tabletop kind, and convert it over with a kit put together by ES-Technical http://www.estechnical.co.uk/reflow-controllers/toaster-oven-reflow-conversion-kit
That conversion will allow it to solder SMT pcbs, handling proper temperature profile, ramp etc.
Its going to chew some time up to do that, then mount the chip (fingers crossed!) and then connect it (via 3.3v <> 5V level shifters) on I2C and start thinking how to read it since there is no ready built arduino library
But the reflow oven could be really useful later also, since I want to boil some of this stuff down onto proper PCB's I can have made. And it opens the doors to using parts that are beyond hand soldering.
this is the oven I will be converting : http://www.amazon.co.uk/exec/obidos/ASIN/B003SE88Z4/ref=ox_ya_os_product
hi folks, been busy as usual, over the bank holiday weekend I modified a toaster oven preparing it for use as a solder reflow oven. Just about configuring it up and testing now, may need a few more mods before its ready to use but getting there!
Im using a consumer toaster oven, "Andrew James GT20C" and http://www.estechnical.co.uk/reflow-...conversion-kit so this doesn't turn into its own lengthy project (I hope!).
Heres some pics of whats happened ;
Im using a consumer toaster oven, "Andrew James GT20C" and http://www.estechnical.co.uk/reflow-...conversion-kit so this doesn't turn into its own lengthy project (I hope!).
Heres some pics of whats happened ;
And some people say that weed smokers are stoners, NO,, just more creative i think :High 5:
I have one more led panel to make before i start with the arduino ph thing. So it will not be in the near future. Low cash flow
But it's on my to do list
I think your right about the public server thing. And the Raspberry pi is easy to setup as a server.
Keep it up. i can see you have your hands full :smokebuds:
Peace
I have one more led panel to make before i start with the arduino ph thing. So it will not be in the near future. Low cash flow
But it's on my to do list
I think your right about the public server thing. And the Raspberry pi is easy to setup as a server.
Keep it up. i can see you have your hands full :smokebuds:
Peace
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