D.I.Y. DMX tester/handheld controller/remote focus unit


Active Member
I've been very happy to find I'm not the only electronics nut on ControlBooth. There seem to be a few of you who are into do-it-yourself projects. The Terg had some questions as to how to build a simple DMX tester. We took the discussion into private-message-land for a while, but the bottom line is that I've designed one. It's a little battery-operated gadget that generates 8 channels of DMX-512, but can map them to any 8 of the possible 512 addresses in a DMX universe. A rough guess is that the bill-of-materials will be about $30, including a little plastic box to put it in. It's not a gadget I intend to build and sell, just something for the do-it-yourselfers. However, as I mention in a note I put on the schematic, if there are enough do-it-yourselfers interested, I can get PC boards made, which I'll sell at cost.

It's built around a little (20-pin) microcontroller from Philips Semiconductor, the 87LPC767. I chose this chip because it has a four-channel analog-to-digital converter (to read the settings of four faders), a microprocessor (to put those settings into a DMX-512 packet) and a serial port (to send the DMX packet) all in the same tiny chip.

You can look at (or download) the schematic here. A .hex file for burning the program into the microcontroller is here. If you want to know how the program works, the source code is here. I'm working on a "theory of operations" to be posted soon.

Thanks John, this will make a nice little addition to my tool kit and be perfect for those small shows where I only have 2 units to control for simple colour washes. For this purpose I will probably add a dc input.

Have had absolutely no experience with burning EPROMs but I do recall being given the 'box' some years ago when a company closed down. So this is something else to learn. However, if I manage to balls it up I will certainly put my hand up for a chip.

Count me in for a circuit board if you have enough takers as I have not done this since high school and just quickly glancing over the schematic I am thinking that there will be a lot of jumper wire in doing this on a breadboard.

If you made up enough for the circuit boards, I could certianly use one..

Otherwise I was thinking of creatine more of a keypad based entry system for non-moving lights...

I believe I may be in for an EPROM burning tutorial as well. I figured Id wing it, but maybe it would be a good idea to look it up...

Know any good sites showing how?
There are almost as many different methods for programming EPROMs as there are EPROMs - it's what keeps the programmer companies in business. I need to do some digging - a few years ago, when I first used this family of chips, it was so new that I didn't have the right algorithm for it on my commercial programmer yet. I designed a programmer specifically for it - which means I should still have the information as to how this chip is programmed somewhere around here... I'm a packrat and rarely throw anything out.

Im going to attempt to build it. :) I think it would be a great idea and I am sure to use it a heck of alot. If you decde to order those boards let me know.
As you will have noticed from my edits of the first post, I finished the program, built a prototype and tested it. I used it to control one of my American DJ "PocketScan" moving mirror effects. It took a little debugging, but the source and hex files I've posted are what is currently running in my prototype.

There are two minor differences between the prototype I built and the schematic I drew. The schematic shows a 5-pin XLR per the DMX-512 spec., but I used a 3-pin the match the cheap ADJ gear I've got. The schematic shows a 9-volt battery for power, but, for testing, I used my bench power supply to be able to adjust the voltage and see how much current it draws. It uses about 25 mA, not a very heavy drain on a typical 9V battery, and works properly with a voltage of only 7.2 volts, meaning the battery can get pretty low before it stops.

Wow! This is pretty much Mecca for cool programming + DMX stuff. Thank you all for your posts here!!

DMXtools (master of the DMX universes) said:
However, as I mention in a note I put on the schematic, if there are enough do-it-yourselfers interested, I can get PC boards made, which I'll sell at cost.

Did you ever decide to make the PCB? I know this thread is probably stale, but just wanted to test my luck. If you're still looking for interest, count me in. Actually, count me in for (10) or so (maybe more?). I often do installations where I need a simple little controller for one or two moving lights in a largely architectural setting. This could be a really nice solution for the clients who won't shell out the cash for a 'real' controller...

I never claimed to be "master of the DMX universes" - just an old fart with a lot of interest in DMX-512 and a few ideas I think are neat.

A few days ago I visited Ship at his place of business. They do lighting and transportation for a lot of really major concert tours. He gave me the grand tour - it was like lighting heaven! Drool, slobber! He apologized that there was so little there because they had several tours out. All I saw was what looked like enough lighting gear, truss and portable staging to do four or five Pink Floyd concerts simultaneously.

The main reason I mention it is that he showed me their Palm Lynx - I guess it's a product they make and sell through some marketing company. It's a little handheld unit that runs circles around this little toy I whipped up. Especially for troubleshooting or focusing movers, it looks to me like it's the gadget to have. Perhaps he can enlighten us as to where they might be purchased.

Thanks John.

You may have opend yourself up in the last post. Some one may just quote you as "DMXtools - just an old fart with a lot of interest in DMX-512 and a few ideas I think are neat." Not that I would do anything like that!

I certainly do hope that Ship posts some info on the "Palm Lynx" that you describe. It would be good to see the features/price.

We could all run out and grab Martin's "the wife" but I certainly know that I would only use a few of the many functions that it has. And for the price that they retail at, it makes much better sense to grab something that is more suited (and priced) to what I need. I guess that it comes down to what the features of the product are, and for me, it will be the ability to quickly and easily test a unit or do some basic scenes if required.

Thanks for the info and I look forward to hearing from Ship. Also, what is the state of play with the one that you posted the schematic for - did you get enough interest to warant producing the boards?

DMX Tools is very much overstating things. First, it’s a overgrown cave that was out grown at least five years ago. At least half to two thirds of our gear is always out on shows, another 1/4 of it at least is in storage in a faculty 80 miles away, and at best he saw 1/4 of the gear we own or 10 to 20% of it. The guys out in Scychamore know a lot more than I do about what we have in storage beyond some Stones and AC DC sets. This would include my mint condition Kliegl Dyna beam - at least it had better still be... Of that, there was nothing interesting going on that day either because everything of value was out and it was a slow day for once. When gear comes back you are lucky to get from one end of the shop to another, much less when a tour hangs it’s rig. There might have been assorted gear on the shelves but there was nothing enough for a good sized show. Fourth Phase, VLPS, Veri Lite and some Euro companies probably still eclipse our scale. Might be in the top ten but I don’t know where we are in that grouping, I’m a stage tech not a rock and roll tech, and we don’t do much stage work.

In other words, of what he saw even Frost Lighting probably will have had more or the same amount of in stock thus the flattery. Thanks, but not necessary. Let's just put it as lots of job security.

John gave me a sample of his adaptor. I gave it to someone that does side gigs and he was very impressed and thankful. More so, I also showed it to the person that designed our below Palm Lynx and Data Lynx, and he was very impressed both with the quality of materials and workmanship on Tool’s equipment, and abilities as a electronics person. Him being impressed is to say the least and very unusual for this person.

Ok, I don’t advertise who I work for. Personal choice, but when I’m home I am me not who I work for nor do I want them responsible for or linked to what I say. It’s a big business that’s very small and memories are long. I have enough problems stepping on my suppliers toes and don’t need more problems when not at work, or off time being tied to on time. If my own authority and respect is not enough weight for my words, the place I work for will not be enough either at best. Nor do I want where I work to seem any better than any other place to work, it’s simply where I have been for five years now, before that I was a Master Carpenter and a frequent free lance designer and tech person. That remains who I am when not worrying about reselling par cans that are not electrically safe much less any other work being done to them but going out the door “as is” as misunderstood to mean not show ready as implied. Different battles different places. As long as I’m implied to be responsible with the gear we sell or use electrically, the gear will be safe or I’m gone. Simple as that, my own responsibility. What everyone else does I cannot be responsible for thus do not want where I work liable for.

Think I did tech in my first show 8th grade, in 1980 - “Pipie Longstocking”, since than I have very much lost count of how many shows I have designed, worked running crew for, worked on professionally or non-professionally, much less those from in school. Also I do not want to curtail what I write as being the official word instead of my opinion, nor the implied liability. Nor what I as an individual representing them as a whole because there are a whole lot of people working there. I supervise one part, there are many more people there who manage and work in different parts. As I said on another post, I blow up Mac 2K fixtures when I get near them. Assuming I have some usefulness, it’s certainly not on the money making part. Nor the sales part, I will not sell to those I help on line unless it’s something they cannot otherwise get. Ask who you can get a lamp from, where I work will not be on the list unless it’s part of a huge list of suppliers. That said, good. You temporarily know where I work, not that it’s a secret, now forget it because Dave will hopefully be removing that specific by request.
My affiliation or standing where I work is not public knowledge though it’s not hidden either. I’m the #12 person on the contact list and under support staff heading. There I am... That’s a very broad non-specific title because I don’t have one. My boss is the Equipment Manager, I don’t have a specific title other than his assistant or as the lamp buyer as I have become known as. But I’m in a very good company that is many times larger than even the contact list and is one of the few that takes really good care of it’s employees in general. Given it’s also defendant upon their value and I’m about mid way to half up on the list. In other words, because I have a real desk of my own and it’s in the front office, I qualify for premium parking. This is a inner office joke I had to ask to verify. Given we were voted Entertainment Lighting Company of 2003 and one of the largest in the world, we were not last year nor I think the year before thus there are many similar compaies. I have a key role there, be it as it may, what I post is not linked to them - two different parts in my life. Never heard of them before I applied. That said... good we will get on with it.

We use three and a half mini controllers.

Two are from Goddard Design Co.

First is the LIL DMXter of which from the 1/17/98 manual the general description follows:

The Lil'DMXter is a portable test set for checking DMX512 transmission and reception. It is also a cable tester
for DMX512 cables, testing both continuity and data transmission.
The unit is built into a water-resistent case. It's pretty rugged - but the display is glass so please use reasonable
common sense care.
The Lil'DMXter is battery operated using rechargeable batteries. We ship it with a good charge, but you may want
to plug it in overnight to top it off. Use the line cord provided to connect to a 120VAC outlet. Your Lil'DMXter
will run while plugged in as well. Units may be ordered strapped for 230VAC operation.
Your Lil'DMXter is a software based machine that uses a menu structure allowing you to step thru its features to
get to the test you need to perform. Much of its operation is obvious. The purpose of this manual is to help you
run it quickly, and to find the section you want easily.

This is the basic troubleshooting and portable DMX controller/reciever in a small case signed out for shows. It transmits DMX, Recieves DMX as per a monitor, Tests Cable or signals, allows for a pendant controller to adjust the levels, or I believe can be used in series with other controllers to adjust the rate of them or clear their levels, it can also tack a snapshot of what the levels are and store them into memory or allow you to go back into them to adjust. In transmitting data, you can control one, some or all DMX channels. The controller also will store up to 5 scenes or parameters of DMX. Lots more about it, I tink it allows for “break times” between the scenes so it will auto fade between scenes, and a huge amount of other things....
This would be the main portable really small controller for say an individual fixture group too small to run off a real light board, or the show support test and prep tool. Even has a kind of oscilloscope feature for the DMX signal. This would be for small shows not complex enough for a Data Lynx, or in addition to it.

The Mini DMXter from the above company is the little brother of the Little DMXter. Less features and more like a GAM DMX tool. We only have one of them and it’s only used when the Little DMXters are all out on shows. Normally otherwise they won’t take it and will just use their Palm Lynx if shoot hits the fan.

After that and on just about all shows we use a back up board and controller our head electronics person came up with and as DMX tools mentions, is sold by TMB and on their website.

Basically it’s a one rackspace thick backup board out of it’s Version 2.4 manual which is a few years old now, and I’m removing the basic Thank you for buying type advertising out of the introduction:

.... When data is interrupted for even a few seconds, many fixtures will behave
poorly at best. It is imperative that intelligent lighting stays “online” at all times. The DMX Data Lynx was designed to be your total disaster recovery and trouble-shooting solution.
We have condensed a vast amount of powerful features into a single rack space unit. The opto-isolated DDL-1 will give you the peace of mind that the show will go on, even if the main console won’t.

Key Features List
*Instantly switches between any two DMX consoles with up to four outputs each, with no cable swapping.
*Buffers DMX data for extended cable runs.
*Records or creates up to 10 back-up looks from the main console in seconds. 2048 channels each
*Quickly accesses any or all of the back-up looks using a “GO” button; either manually or automatically.
*Performs all standard DMX test routines (Transmit Some, One, All, Auto Fade One, Auto Fade All channels).
*Displays data as decimal, percentage or hex.
*Transparently reads, saves and diagnoses DMX data packets; even during a show.
*Tests multiple moving fixtures at any starting address using PC editable fixture libraries.
*Tests cables through the entire system, including through opto-splitters.
*Incorporates opto-isolation on all inputs and outputs to prevent ground loops and static problems.
*Front panel LED’s display the user configuration and data status at a glance.
*Convenient internal voltage select switch for 115VAC or 230VAC operation.

There are a few controllers like that above I think. It's also an older version of it. TMB would have the latest description on their website, and they are probably not cheap.

As for the Palm Lynx. We sell them but only make about one batch of them per year. I have an old disk copy of the manual that does not include the five scenes worth of memory you can import or write as a scene. The main purpose of it is not to replace the above three controllers, more it is a DMX controller the size of a wallet designed to take up on the truss with you or be otherwise portable. It does not have a plug in feature about it and while it will last on a 9v battery many hours, given you are not in auto-shutoff mode, it’s intent is not really to run a show unless you are in a pinch or just want to create a few looks without a lot of cabling. My primary use for the tool is in testing DMX fixtures such as strobe lights, using it’s receive mode as a monitor down line from the controller such as at the dimmer, or transmitting the data directly at the dimmer pack to troubleshoot. Makes life a bit easier with a small transmitter. They sell for about $350.00 each but I don’t know when the next batch of them is going to come out. I will forward anyone interested to the person that makes them but don’t do sales. Contact me off forum if interested, again I don’t know when they will be built next and many employees are on a waiting list for them already. It is a cool unit and it stores in memory data for testing most moving lights on the market with room for specific upgrades in others. We get to buy one of them at cost with it taken out of our paychecks. The idea for the moment is not to market them much but to make them for employees with oh’ by the way some made for others.

Otherwise at least at one point the designer and I were talking about coming out with a stage version of it. Basically remove the moving light fixture menu and you now have room for more memory scenes in addition to up and down fade times. That would be a good and cheap backup board, but as it stands, you can go to scenes but have no control over fade rates much less groups. Once in a scene you can only control one or all channels as it stands. In other words, while useful as a analysis tool and especially for moving lights people, for stage as a back up light board, you have to be really desperate to just have a few scenes in memory to use it.

As follows in the version 1.2 Palm Links 4/00 manual - since upgraded - I think we are on v2.4 now.
The DMX Palm Lynx (DPL) was designed to be the DMX Data Lynx’s (DDL)
little brother. The DPL gives you many of the same features as the DDL, but
in the smallest possible package.

Key Features List
Transmit Mode
. Offers all standard DMX test routines
(Transmit Some, One, All, Auto Fade One, Auto Fade All dimmers).
Receive Mode
. Display 512 channels of incoming DMX data.
Fixture Test and Download Modes
. Test any moving fixture at any starting address.
. No need to memorize DMX channel assignments; the unit displays each
parameter being tested.
. Holds one fixture library in non-volatile memory.
. Easily, create or customize the fixture libraries on any PC.
. Download current fixture libraries from our website and load them via the
PC serial port.
.Accepts a fixture dump from the DDL-1, DDL-2 and PC’s or Macs running
Soft Windows.
. Display DMX data in decimal (0-255), Hex (00-FF), percentage (0-100%).
. Easy to read high contrast 16x2 character LCD display.
. The DPL can operate an average of 20 hours on a single 9 volt battery .
. Fixture memory can be retained for over a year in shut down mode.
. Auto Power Off feature turns the DPL off after 5 min. of inactivity.
. The DPL comes equipt with a 5 or 3 pin female XLR on a whip to make it
completely self contained for transmitting.
.Adapters are available to provide the necessary turn-around to enable
DMX receive.

Anyway that’s the main mini light boards we use.

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