Raspberry Pi Forums

BAStumm

i2c is setup and working. I have a mod-tc-mk2-31855 thermocouple uext olimex deal hooked and working too. It is hooked to the top of the adc-pi. What should it return? It's returning zero. pi@raspberrypi:~/wiringPi/examples$ sudo i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -...

BAStumm

Oops you did that, look at the commented line about bus. You are trying to use bus 0, you need bus 1.

BAStumm

Have you tried running i2cdetect from command prompt? If you have the earlier 256MB board use 0 instead of 1. pi@raspberrypi:~/wiringPi/examples$ sudo i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- ...

BAStumm

Here is what I came up with as a quick test. Not sure if this is working or not, have the adc-pi connected to the RPi but nothing connected to it just now. Question, where does the 400 value come from? Can I assume that 400 - 403 are the 4 channels for this i2c address? This board has 2 i2c's each w...

BAStumm

Thanks for the help gentlemen, changing baudrate to 32000 shows a device now listed at 0x48. This also confirms to me that the devices I have are using an older version of firmware. For latest version it should have shown up at 0x23. I intend to customize the firmware anyway. I'll do some further te...

BAStumm

I've already cut the pads to remove the resistors, no luck there. Found that the previous firmware for the board included a i2c-tool.c program that accesses the hardware differently than the linux i2cdetect program but no luck there either. Not sure what firmware is loaded on the board at this point...

BAStumm

Been struggling with i2c for a day already, looking for advice. I have a few mod-tc-mk2-31855 boards, basically the max31855 thermocouple chip with a pic processor that adds some analog and i2c interface. After struggling for many hours yesterday I decided to start fresh with a newly installed, late...

BAStumm

Plus I am already using many of the RPi GPIO's for reading other (digital) inputs/sensors and pulsing step motor drivers.

BAStumm

I need to read up to 12 thermocouples... each one has also a current transformer which requires analog. This board seemed ideal since I can have a thermocouple and analog channel at each "zone of heat control". Plus I want to store custom firmware on the pic to fire an SSR, read wattage an...

BAStumm

Has anyone tried interfacing one of these to the RPi? MAX31855 Thermocouple and PIC16F1503 for I2C communication, program storage and additional Analog and Digital I/O. Planning to use this to read thermocouples and a current transformer for heater control with closed loop temperature and wattage co...

BAStumm

Thanks... I had a feeling it was the same (except i2c vs spi).

BAStumm

I ordered two of those ADC Pi units today for a similar application. For DC you want a current transducer instead of a current transformer, I think. Not sure about sensing 7mA as that is very low. Can you hack into the power supplying the led and just use that as a digital input to the Pi? I think y...

BAStumm

You will need analog inputs for the Pi, they are not built in but there are some add on cards. There are AC and DC current transformers that work for low current. Some are even just indicators (current is flowing or not flowing) if all you want to do is determine power state on or off. In this case ...

BAStumm

Gordon, Where is the code for the ADC Pi board within wiringpi? By this I mean the one in this link which I believe you referred to in this post. http://www.abelectronics.co.uk/products/3/Raspberry-Pi/17/ADC-Pi-V2---Raspberry-Pi-Analogue-to-Digital-converter I just ordered 2 of these and it would be...

BAStumm

I've used the big easy driver from SparkFun, works well. 35VDC, 2amp. Works well with NEMA 23 motors. For NEMA 34 motors I use the gecko drive but it is about 3-4 times the cost.

BAStumm

Apologies if this has been asked, I did try searching and found limited information. Who is using an off the shelf, semi professional, optocoupled input board for their projects? Just looking for alternatives at this point as I have a couple of these, http://www.elexol.com/IO24Accessories/Opto_Input...

BAStumm

RPi is 3v3 on the GPIO so you may need to boost the voltage before it reaches the relay. This would work. https://www.sparkfun.com/products/9118

Just provide 5vdc for the HV side.

BAStumm

Nearly anything is possible, the thing is that the RPi lacks the isolation required to interface these other voltages you might require for real world automation systems. I'm using the RPi to control step motors and relays while reading sensors. You just need to provide your own opto-isolation or wh...

BAStumm

Just make sure the relay can latch using 3.3vdc on the input side. The relay output pins will close the connection on the motherboard. The motherboard is providing it's own power and the relay is like a light switch (open or close the circuit).

BAStumm

Anyone using power supply other than the typical cell phone charger? For my project I need to have 5vdc (to power the pi) and 3v3 to supply my Input (opto) board. I'm using these (this is 5vdc but I also have 3v3 from same manufacturer): http://www.ebay.com/itm/Waterproof-DC-DC-Converter-12V-Step-do...

BAStumm

Also, you might want to connect a RPi pin to the enable of the stepper driver. This would allow you to disable the driver when not rotating the table and keep the driver cooler. Otherwise the driver is always enabled and when not turning the motors will "lock", depending on how easy your t...

BAStumm

No sweat... I'm actually working on something that uses the step motors myself so I had most of this done already. My application has the motors running continuously at a certain speed for a conveyor application but switching modes to control to a certain angle was fairly simple. FYI, all the hardwa...

BAStumm

Quick example code, messy and may not compile as it is not tested. turn.c execute with "sudo ./turn 800 1" where 800 is number of steps and 1 is rotation direction. This will turn a full revolution in 3.2 seconds, adjust delayMicrosenconds to speed up or slow down. Low torque motors may no...

BAStumm

Your turntable should be easy enough... Get an opto isolator like this: https://www.sparkfun.com/products/9118 Then get a stepper driver like this: https://www.sparkfun.com/products/11699 To simplify things you could use wiringPi, http://wiringpi.com Hook two Pi pins to the two opto inputs (3.3vdc) ...

BAStumm

\r\n if you wish to use the code on other platforms... Not that any of us are running windows on an RPi.

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