Chris Bott - Moderator Posted May 23, 2020 Author Share Posted May 23, 2020 Dennis, thanks for pointing that out, the 1uF tant is indeed C1 and not C2. I'll correct the bill of materials. -ve end goes to ground which is a thicker PB track. Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted May 24, 2020 Share Posted May 24, 2020 Chris, Is the software in the Dropbox contain the latest updates? Thanks. Dennis Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted May 24, 2020 Author Share Posted May 24, 2020 Hi Dennis yes the latest version is V0.3. Here's all the links etc in one place. Sketch OLEDPwrMtr V0.4.ino (V0.4 includes the change to the line three posts down). .stl file for PP3 Battery Box .stl file for Middle section .stl file for Bezel/Front is from the bottom of this page on the Bitsbox website Bill of materials Edited By Chris Bott - Moderator on 02/06/2020 21:31:01 Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted May 24, 2020 Share Posted May 24, 2020 Hi Chris, The board is built and the Minipro 328 has accepted the sketch so its ready for final testing. Can you please run through how I setup the calibration of the unit using the two trims. Thanks Dennis Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted May 24, 2020 Author Share Posted May 24, 2020 Hi Dennis. That's sounding very positive. All I do, to be honest, is:- Adjust volts - Apply a voltage to be measured, I tend to use a 1S battery for this because that's the typical use case, and check this voltage at the same time with a multimeter. Adjust Trim V until the readings match. Then if you like, try at other voltages. Adjust amps. This is a little more tricky as you need a source and a load so that current passes through the unit. I use a bench power supply that has a current limiting adjustment and a car headlamp bulb. I put a multimeter in series with the bulb, on it's 10A range. Then I adjust the current to something like 2A on the multumeter and adjust Trim A to make the wattmeter read the same. I then try at around 1A just as a check. Without the adjustable supply you could use a battery but will need a load that will draw an amp (or two amps). The actual value doesn't matter as long as you can read it with the multimeter in series at the same time. Even powering a model via the wattmeter and a multimeter in series will do, although you may find there's too much volts drop through all those wires to allow the model to start up. Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted May 25, 2020 Author Share Posted May 25, 2020 Dennis, if you're still looking in, I've calibrated 3 new meters this evening and all 3 couldn't be adjusted quite enough on the current range. I can only assume that this batch of resistors have slightly different values to ones I've used before. So, I had to alter the multiplier in the line measuring current to 45. i.e:- Amps = (((Atemp+LOOPS/2)/(LOOPS))*((1.1/1023.0))*45*TrimA)+0.11 ; Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted May 25, 2020 Share Posted May 25, 2020 Hi Chris, Haven't got that far yet but still making progress. I ordered my screen very early on when Bitsbox didn't have any in stock so got mine from Ebay. As far as I could tell they looked the same as yours but the pcb seems to be bigger as it doesn't fit your box and there are more pinouts on mine! Finally got it working using the following conversion table Arduino pin no. motherboard socket pin No. New screen connections VCC 1 VCC GND 2 GND 8 3 CS 9 4 RST 10 5 RS 11 6 SDA 13 7 CLK I am at the stage of setting the input voltage on a 3 decimal place digital multimeter which seems very stable. I'm using a 1 cell lipo to set this, will attempt the current setting tomorrow. Will come back to you with my findings. Regards Dennis Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted May 25, 2020 Share Posted May 25, 2020 The spacing of the table didn't come out as expected when I uploaded it. Example: Arduino Pin No: =VCC Motherboard socket pin number: =1 New screen connection: =VCC Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted May 25, 2020 Author Share Posted May 25, 2020 Blimey, that's a complication you could have done without. Well done on persevering. I look forward to seeing your finished unit. Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted May 26, 2020 Share Posted May 26, 2020 Hi Chris, I’ve noticed occasionally that after switch on I’m getting a white screen, to restore the program I’m having to use the reset button on the Arduino to get the program to start. Have you come across this before? Dennis Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted May 26, 2020 Author Share Posted May 26, 2020 Hi Dennis, No, I always see a white screen for a second or two, then that gets replaced by the expected screen. I've never had one stick at white. Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted May 26, 2020 Share Posted May 26, 2020 Hi Chris Just gone through the current setup and the unit is reading high, see below 5.54V------- Meter reading 0.530A---------Ardunio reading 0.53/0.58A 7.64V------- Meter reading 0.730A---------Ardunio reading 0.80A 10.26V------- Meter reading 0.991A---------Ardunio reading 1.06 This was with the current pot at its lowest setting. I am going to load your mod above and come back with more results Dennis Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted May 26, 2020 Share Posted May 26, 2020 H Chris, Thats got it. Current readings now matching the digital meter. Now to fit it in the box. Dennis Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted May 26, 2020 Author Share Posted May 26, 2020 That's great news, thanks Dennis. Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted May 26, 2020 Share Posted May 26, 2020 Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted May 26, 2020 Share Posted May 26, 2020 Works well and accurate. Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted May 26, 2020 Author Share Posted May 26, 2020 Looks great. You're right, the display does look the same. What a shame the pinouts are different. Quote Link to comment Share on other sites More sharing options...
Phil Olson - Model Technics Posted June 6, 2020 Share Posted June 6, 2020 Just in case anyone has a problem I had to install the Adafruit VEML6075 and Adafruit BusIO libraries as well as the GFX and ST7735 in Arduino to get it to compile without errors Edited By Phil Olson - Model Technics on 06/06/2020 20:10:14 Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted June 6, 2020 Author Share Posted June 6, 2020 Thanks Phil. Useful info. I guess I installed those a while ago. Quote Link to comment Share on other sites More sharing options...
Phil Olson - Model Technics Posted June 9, 2020 Share Posted June 9, 2020 not quite finished but at least it works ( I got my display from ebay !!) Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted June 9, 2020 Author Share Posted June 9, 2020 Excellent, it's really nice to see the fruits of a design when it's put together by someone else. Thanks Phil. Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted July 9, 2020 Share Posted July 9, 2020 Hi Chris, could you explain an anomaly I have come across. I am running the units on V4 software and have noticed the “Min Volts” is recording what appears to be the maximum voltage of the cell. I was expecting the cell voltage to drop in use and with a volt meter across it it does, but the Wattmeter is still recording the higher voltage that was there at switch on. The “volts” value faithfully follows the state of the voltage on the cell. I replaced the 1 cell with a power supply and the unit was the same. When I lowered the voltage on the supply the wattmeter only recorded the higher initial voltage in “Min Volts”, but if I increase the voltage (something that would not happen in the real world) the “Min Volts” alters to reflect this increase. Are we recording the Max voltage of the cell, and so should the labelling change to “Max Volts”? Regards Dennis Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted July 9, 2020 Author Share Posted July 9, 2020 Hi Dennis, I have to leave the house in 5 mins do this is off the top of my head. I (think I) have it saving all 3 readings when power is at a max. I did try recording all 3 independently, when they hit max or min. But often found apoarent anomalies between the saved max watts and the multiplied max amps and min volts. Would this explain what you're seeing? For the intended application, I think saving all 3 with a single trigger makes sense? What do you think? Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted July 9, 2020 Share Posted July 9, 2020 Hi Chris, so if the value is that at "Max Power" maybe the Min Volts & Max amps be relabelled to MPvolts & MPamps? At the moment its a bit confusing. Dennis Quote Link to comment Share on other sites More sharing options...
Dennis Mulhair Posted July 9, 2020 Share Posted July 9, 2020 Then again I suppose if I was measuring in the real world using say a 1 cell LIPO and an actual motor and esc the readings would make more sense. I will try this tomorrow. Dennis Quote Link to comment Share on other sites More sharing options...
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