ALCS 7-speed EXR external crystal control box

[Aapo Lettinen]

I started to design the external control box which replaces my aluminium body Universal Motors after May2027. 

I am assembling external control boxes which have simple 4pin gx12 connector and can connect to all kinds of DIY camera motor systems which use 0-5V analog control line for brushless motor speed control, are driving the camera direct drive with 1:1 gear ratio and have a brushless motor with 4 pulses per revolution from each Hall sensor. It is basically the crystal control board of my 6-speed EXR universal camera motor with the switches added to the panel. 

Typically one would build a diy motor unit and use a simple Chinese bldc board which is slightly modified and 42bls01 type brushless motor. The DIY motor one makes has the bldc board and the brushless motor drive and power connector and fuse, and it is connected to the Crystal Control Box made by me via 4pin cable which feeds power and Hall sensor signal to the crystal control box and brings back 0-5V speed control line from the crystal box to the DIY motor's bldc board. I designed it so that electrical connections inside the DIY motor are very simple and easy to arrange.

One special benefit of this external control box is that it is possible to use one control box with multiple camera bodies very easily if only shooting with one of them at a time. Just keep the diy motors attached to the camera bodies and swap the control box between them whenever needed. Switch off power, take cable off from the box's connector and move it to another camera and attach there. takes 30 seconds or so.

Control box dimensions are about 60mm X 65mm X 35mm for the box itself and it will have M4 and 1/4" mounting points to rig the box anywhere you want. It will be designed so that you can mount the box easily to the side of DIY camera motors "permanently" if needed and run the connector to the motor. 

The control panel can be flipped upside down to get the cable connector to the left side instead of the normal right side of the box. 

The crystal controller has a built-in start-stop push button on the panel. It is a momentary working switch. There is a connector on the circuit board if wanting to get additional start switches wired to the box directly but I recommend leaving the box just as is and if needing additional start switches mounting them to your DIY motor part instead, then it allows making a diy motor which has wild variable speed too if needed.

I will design some kind of 3d printable or cnc-machinable "universal motor style" motor unit which can be made from step files and diy assembled. you can design your own motor unit easily too. The same mounting parts which my Universal Motors use for ACL, Kinor, Krasnogorsk and Konvas are available with all purchases as step files so you get really good value and maximum design freedom when purchasing this external controller. It can easily control diy Eclair NPR motors too. 

These 7-speed EXR controllers are fully compatible with my original 16-speed and 12-speed Eclair ACL motor units and use the same cable connection so if one has one of those old motor units one can directly drive it with this new control box. AND for people who wonder what's the big idea with the separate control box, check out my 16-speed and 12-speed ACL controllers on youtube, you will see what these external boxes are good for and why I like designing this kind of stuff.

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These are already possible to order, I am sending the circuit boards and control panels to manufacturing in October as I will start assembling test boards in November and designing the casing during Winter. Estimated shipping would be starting from April-May 2027. 

Price if ordered before November2026:   380 usd outside EU / 380 euros in EU with vat. Includes shipping.

Price if ordered between December2026 and January 2027:  420 usd outside EU / 420 euros in EU with vat. includes shipping.

Price between February 2027 and April 2027:  450usd / 450 euros

Price from May2027 onwards:  Availability and price tba. Might go to 500usd/eur or more.