IC-705 Elecraft T1

IC-705 Elecraft T1 control interface

Elecraft T1 controller with auto power shutdown for ICOM IC-705

This is the partial final version of Elecraft T1 controller for IC-705. ( PIC12F683 )
From previous version, I changed its program (added Sleep command), and added auto power shutdown function.

How to use this controller:

1. Connect elecraft T1, IC-705 and antenna with the appropriate cable (usually coax cable)
2. Connect this controller to T1. The controller will wake up automatically.
3. Connect the controller to IC-705.
4. Switch ON for IC-705

Now it is ready to use.
Please note that, while the controller is connecting to T1, it draws approx. 184 uA (micro Amp) and when you connect it to IC-705 and T1, it will be jump up to 1100 uA of electricity from the battery.

When you stop to use, take a opposit step from 4 -> 3 -> 2 ->1.

Even if you disconnect the controller from T1 and IC-705, there is some electricity will be consumed. (approx. 30 uA) This is stand-by mode, before going into sleep mode. Approx. 1min after, it will sleep.

The controller will consume 300 nA or 0.3 uA. So far, I am using Ni-MH battery. And I believe the battery’s self-discarge will be bigger than this dark current.

I am satisfy with this study result, so this series will be closed for a while.
Constructive comments are welcome, but I am not good at English, so please allow my response may delay a lot.

Before closing, I need to inform with you as,
– This is my personal experiment and it is not gurantee that you can get same result even if you copy this.
– I can not take any responsiblity with you, your propaty’s damage or any loss by using this blog’s ideas.
– You can use this idea as your personal porpose, but I have copy right of this.

Thank you and enjoy!

IC-705 Elecraft T1



You can use Google translate to translate all the information and successfully program the PIC chip

Here is a Youtube link.

IC-705 Elecraft T1 controller with Low voltage battery

Even I have concluded T1 controller project, still I would like to try to expand battery life with low voltage type PIC.

As you may see my other blog, only 3V battery (CR2032) can let IC-705 to TUNE mode, so I tried to find a suitable PIC in my junk box and found 12LF1822 (Power source 1.8V – 3.6V, 30nA at sleep mode).

I suppoce this voltage is out of Spec for 705, but it still works.

I checked battery current, and it result was as below.

Connected T1-Controller-705 and switch off conditon of 705
Previous 1076μA  →  New 34μA

Disconnected T1,Controller and 705 (just before sleep mode)
Previous 29.3μA  →  New 4.4μA

Sleep mode (I could not measure it, so the info from the Spec sheet)
12F683: 350nA,   12LF1822:  30nA

For your reference, I attached Circuit diagram and Program. The logic of the program is not changed, but 12(L)F1822 is newer from 12F683, and its port name etc. is different, I adjusted that part. In the diagram, I changed a value of resistance that is connected to MOS FET for reducing current consumption.



You can use Google translate to translate all the information and successfully program the PIC chip


There is a precaution. If you disconnect T1 and Controller while 705 is a Power On condition, the controller will make 705 to TUNE mode and the 705 will start to transmit radio signal. To avoid this kind of problems, please turn off 705 before it disconnect from T1 and/or controller.

I tried to this experiment with my set, so even if you copy this set as above, it doesn’t guarantee its function. So please try it by your own risk.

Thank you for reading, and please have a great day!

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