Trouble with Vinotemp RH\temp project - how to take control

[DistrictJP]

Greetings. I've been working on a Vinotemp TEDS28 wine cooler, which I use as a humidor. This weekend I replaced the peltier (I have also replaced the controller board) and the strangest thing is happening.

It's like the temperature sensor is right on the cold-side fins. At first I had the peltier in backwards. I matched wire colors as well as facing the side with letter the same as the one I removed, but almost instantly after turning it on the temp readout shot up to 81+ and the fins were definitely hot. After getting that turned around, now the temp gauge shoots down to 54. The cold fins are definitely cold but since the Vino thinks it is 54 inside it turns off the fans, and there is no change in internal temp.

Any ideas here? I can patch the connector pins to a breadboard and an arduino but am not proficient enough with electronics to be sure I wouldn't blow anything up. How could I go about using the arduino to send the signals to turn on and off the cooling in response to a different sensor, and a different readout?

I basically am asking how to leverage all the existing cooling electronics - can it be as simple as learning how to send the right signals to the control board on the Vinotemp?

Any advice is greatly appreciated. This is as much a learning project as it is for practical use.

jp

 

[chuckey]

It sounds as though the the temperature sensor is not working properly, perhaps because its feed current has changed. I would measure the voltage drop across it at two different temperature to see if the voltage is changing. Is there a preset potentiometer to make up for different sensor characteristics?, could be it is faulty. It is easier to fix the existing sensor circuit then to try to replace it with a different one.
Frank

 

[DistrictJP]

Thank you chuckey! I measured current from what I think are the sensor wires and voltage increased from 13.5 to 15.5 when the cooling system was activated. Can I chain these connections into my Arduino and send the signals I want to the main board to turn on and off the fans and cooling?

There are about ten molex plugs into the mainboard for fans and sensor, it seems like if I could read those signals I could understand what combination runs the cooling and then I would just replay those using the Arduino. I just am not there yet in terms of knowledge for making sure I have the correct components in between the system wires and the microcontroller to prevent damage.

thank you again!
jp

 

[chuckey]

There are a wide variety of ways that the temperature control could be done. How do you set up the temperature? If it done via buttons and a display, then the whole affair could be done in software, the only proviso is that the micro "knows" the characteristics of the sensor i.e. it produces "X" volts at a certain temperature. If the temperature is set by a knob, again the micro could "read" the value of the volts set by the knob and do what it has too. One other way is for the two voltages (sensor and knob) to be compared in a chip which then feeds the micro or the fan circuit directly.

You could find the temperature sensor, Google its type number on the Interweb and see if it is operating correctly.
Frank

 

[dz32]

Hi I was wondering how you made out with this? I am looking to do the same thing. I have a 2 zone vinotemp, lower is running to cold, looking to replace the existing control panel with an arduino reusing the driver board. The built in controls maxes out at 66deg I would prefer 70 to use as humidor. In the event of a power off, the microcontroller also loses the temp setting ans defaults back to 54 which plays havoc with my humidity levels. hence desire to control myself. I am also planning on cutting out the middle divider to make one large compartment instead of two.

On mine the thermoresistor is on the inside, behind the fan cover, little black epoxied stub sticking out of the plastic, I have taken most of the cooler apart to trace wires, its wires do not goto the back driver board. there are 4 wires going into the pleitler, 2 power wires for element itself, and then two black ones that are for a defrost element.

The microcontroller for the temp control has a 3 wire plug connected to the driver board, red, black, and white. driver board will not run if disconnected, i think red/black is the power leads. reads 8v. When actively cooling, the white lead is at 7.5v, and when "idle" its at 4.5 and the fans run much slower. Connecting the power pin to white control pin does not trigger board to run.

Looking at the driver board, it has only 2 ICs. One is an dual opamp, and the other is a PWM power control chip. I am assuming at this point that the while lead is a PWM signal. I think it should work if I wire in a resistor between it and my USB logic analyzer which maxes out at 5v.

you can measure idle state voltages by putting a bag of ice on the thermoresistor. I am not really an electronics guy, just learning in the trenches for fun. Vinotemp also has some good manuals available in their support section. Edgestar has some very indepth service vids on youtube which are quite similar design.

If i can gain control of the driver board, I will add the temp control functionality to this project:

https://github.com/dzzie/humidor.net

does the assumption on the white lead being pwm sound reasonable? I am guessing the voltage drop is the analog appearance of a slower signal being sent?

 

[dz32]

figured out an easy albeit dirty way to control the driver boards. I will leave the existing microcontroller in place and all of the original wiring, except for the thermistors. Those I will clip and wire in a digital potentiometer controlled by the arduino as a replacement. I will just cycle the resistance hi/low based on the reading from the dht22.