TBolt Nuts To keep My TBolt's temperature constant so that the environment has minimal effect on it, I use an aquarium temperature controller (modified to have low hysteresis) connected to a low wattage light bulb, placed in a box with the TBolt. It works OK and keeps the TBolt's temperature constant to well under 1 deg. To do it better and make it more hi tech, I'd like to have the temperature control based on the TBolt's internal sensor.
What I have found works well is to use the TBolt's own RS232 temperature sensor output data, and with a modified PID type of S/W controller, turn an external heater &/or cooler on off. The heater can be an appropriate power resistor or transistor dissipating up to about 4 Watt, mounted to the TBolt case. What I use to cool the Tbolt up to 5 deg C, is a small fan blowing at a heatsink mounted on the top of the TBolt's case. Turning the fan on & off with a S/W driven switch, can be used to keep the TBolt's internal temperature very constant over a limited external temperature range. A standard PC chip fan & heatsink may be OK, if it does not add Phase noise due to it's vibration. Because of the long time constant and slow response of the internal temperature sensor, a single digital on-off bit, updated at a max rate of once per second works great for control, No analog needed. To keep the hardware and interface circuit simple, I'd like to be able to use one of the unused standard RS232 outputs, such as RTS, CTS, DSR, DTR as the heater/cooler control bit(s). This is no problem when doing this in a DOS program or from an added microprocessor that monitors the Tbolt's communications, But the question is, can it be done in Windows in such a way that a modified existing program such as Lady Heather or Tbolt monitor could control an already existing readily available digital bit? Being a control person, Doing a software algorithm is the easy part. Making Windows do any kind of non standard I/O control, is way above my capability. I'd like to get feedback from a Windows expert if there is a simple way to control an existing Digital bit that would be available on a PC being used in a typical setup that is used to monitor the Tbolt. One way I have heard suggested is to use the sound card output, but I'd like to keep it even simpler than that, Any suggestions? If anyone is interested in developing a program to make an existing stand alone micro or basic stamp to include this function they can contact me off line for some sugestions. Thanks, ws ****************** _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
