Simple Biomed project

I work in a biomedical laboratory that performs small animal surgeries on mice and rats. We face the problem of controlling the body temperature while the rat is being operated on. We could buy a expensive solution that costs 3K, or build something similar from scratch.

The temperature of the rat is controlled with a heat lamp. Temperatures are taken with a simple thermometer. The thermometer has a alarm that goes off if the temperature is too high or too low.

I want to build a circuit that automatically shuts off the lamp/dims the light. The lamp will be controlled by using the wires to the speaker to signal the light to turn off or on. (Simple board with a few transistors?)

I am stuck on how to make the small voltage from the speaker control the AC lamp. Any thoughts?

I would recommend a PID(proportioning/integrating/differentiating), "phase controlled", temperature controller module, driving a zero-crossing solid-state relay. The temperature sensor should go directly to the controller, not through an on/off alarm. These controllers generally are programmable for temperature and alarm set points, and have digital temp readouts.

ken

ken

The epoxy coated thermistor must be read by the digital thermometer. The only thing that can be modified from the device is to remove the speaker to gain access to the wires. It is a fisher scientific thermometer that must pass certification and calibration on a yearly basis. Also, the only electronics experience I have is messing around with a few electronic kits.

You can maintain the use of the Fisher Sci. thermometer, just have a second sensor, placed next to the original, but connected to the heat lamp controller. Is the Fisher Sci. probe surface mounted on the rat, or internal?

As an aside...how much money are you willing to spend?

Ken

The temperature probe is an internal rectal thermometer. Below is the link to the exact thermometer. We would like to spend less than $75 + the cost of the thermometer.


**broken link removed**

Are you there Moffet? Anybody else...

deepspacem32 said:

Are you there Moffet? Anybody else...

Click to expand...

Not available to dig into it at the moment.

Ken

Controller CN7523: **broken link removed** $97
Solid state relay SSR330DC10: **broken link removed** $21
RTD Probe PR-20-2-100-1/8-2-E-T: **broken link removed** $60

You would need to provide appropriate housing, power switch, Fuse/holder, power cord set, and outlet to lamp.

Omega is pricey, but it works. If you know what to look for you could pick up a similar controller and SSR on eBay for under $50.

Ken