Digital Doc 5

A good temperature tracker.–Joe

SUMMARY: A very capable tool to monitor temps and control fans – or other 12 volts devices.

Digital Doc 5

The good guys at MacPower sent over a Digital Doc 5 to test out. This enables you to monitor temps and turn fans on at pre-determined temperatures settings. It also monitors power supply voltages as well. A beeper sounds when any setting goes outside the pre-set limits, alerting the user for action.

While monitoring temps, if you turn off the beeper (press any button), it will go on again if temps go up another 5C. For fan monitoring, if the fan fails to turn on or goes below 500 rpm, the beeper goes off. It takes about 80 seconds to scan all 8 temp and speeds.

Lastly, you can monitor the +5 and +12 volt settings within four ranges – 5%, 10%, 15% and 20%.

Programming the Digital Doc is not all that onerous – if you have a VCR flashing “12:00”, then this is not for you. The manual is on a CD and very well written – you should have no trouble setting the unit up. If you do, there is a RESET button that allows you to start all over.

The screen glows amber:


I found that severe off-angle viewing was not that good – the numbers “dimmed down” quickly.

The unit mounts in a CD ROM slot – simple.


All the fan plugs are 3 pin connectors. If you have a four pin fan with a sensor wire, you will have to use an adapter. If any fan does not have a tach output, you can not monitor it. All the fan plugs are labeled, the sensors are not (Note that one of the connectors is routed to the 40mm fan that is embedded in the front of the unit; If needed, I think you can pull this one off and use it for an eighth fan). However, you can easily figure which is which by where they plug into the PCB:


I found it a MUST to label each sensor wire, otherwise you go crazy figuring which is which.

The Digital Doc comes with 8 sensors (somehow I only had 7) of two different types:

Sensor Types

The thin ones can be used for CPU monitoring, most likely slipping it under the CPU to contact the edge. The larger bulb types can be used just about anyplace else.

In the extensive documentation, I can across this in FAQs:

Q: I have found a thermal sensor point on the Intel Pentium board.
Can I feed the thermal signal directly into the Digital Doc 5?

A: Absolutely, we highly recommend this because the Intel Pentium will not give you any warnings about taking corrective measures. Once you plug your thermal signal directly into the Digital Doc 5, it serves as the fire alarm for your system and the fire department for your Intel Pentium.”

An interesting idea!

The documentation states that thermistors of 5 – 15 K ohms can be used; there is a 10K thermistor available from Radio Shack, so if you feel thermistor challenged, you can add to your heart’s content.


I used the Digital Doc in testing airflow HERE. As you can see from this, you can place sensors all over the place. While doing this testing, I checked the temp probes for accuracy:


Digital Doc Temps

Probe #:

  1. 25.0 C
  2. 24.0 C
  3. 24.8 C
  4. 24.5 C
  5. 24.8 C
  6. 25.0 C
  7. 25.0 C

I used a glass of water to stabilize temps. I recorded temps by immersing all the probes in it; the actual temp was recorded at the same time using an Omega HH23 Digital Thermometer.

The Digital Doc was a little over 1 C on the high side, with an absolute variation among the probes of 1 C (this is within the DD’s stated +/- 1C accuracy). This is NOT a laboratory instrument, nor is it intended to be used a such. For relative readings and fan control, its accuracy is fine.


If you have a LOT of fans and crave some respite from the noise, using the Digital Doc 5 to monitor and control them can go a long way to preserving your sanity. It is very flexible and fairly easy to set up and program. For evaluating case airflow and its impact on temps, the Digital Doc looks like a good evaluative tool.

In addition, there should be no reason why you could not control other 12 volt devices (limit 12 watts on each connector) that you might want turn on and off, based on temps. The fan speed monitoring function can be turned off, so the Digital Doc does not care if it is a fan or whatever.

For example, let’s say you want to have a backup waterpump that turns on if the primary fails. You could fit two waterpumps in parallel with one controlled with a 12 volt relay. By placing a thermistor on the waterblock or CPU, if the temp goes over a pre-set limit, the relay would close and the second pump kicks on. Simple and totally effective.

If you think about it, using 12 volt relays could control a whole bunch of more powerful devices (peltiers?) that you might want to turn on and off based on temps.

I’m sure there are other ideas out there as well. I don’t know if you can gang the fan connectors together and control something like a 24 watt device, but that might be kind of interesting also (forget about warranty on that one!).

Consider the Digital Doc 5 a temperature controller and let your mind wander. What fun!

Email Joe

Key Operating Variables:

  • Power Source: Any +12 VDC power source
    (Standard 4-Pin Connector)

  • Monitoring Temperature Ranges: 0°-100° Celsius
    32° -212° Fahrenheit

  • Number of Temperature Sensors: 8 Sensors
  • Temperature Sensor Resistance: Between 5 K and 15 K
  • Temperature Sensor Accuracy: ± 1 Degree
  • Maximum Fan Rating: 1000mA (1 Amp) or 12 Watts per fan

  • Maximum Number of Fans: 1 Built-In 40x40mm Fan
    7 Additional Fans

  • 0 x 40 MM Built-In Fan Rating: 40mA (. 04 Amps) or .5 Watts
  • Power Sources Monitored: Both +5 and +12 VDC sources

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