FWIW, a few years ago, I created my own pacing device because at that time, I was terrible in pacing my workouts. Since I didn't care about spectators or other runners, I chose sound instead of lights and a wearable device instead of 400m of lights.
You'll need some low soccer cones, a GymBoss Plus interval device ($30), the ability to do 4th grade math, and a few minutes to set up. Alternatively, you can use a Tabata app on your phone instead of the GymBoss Plus. Since my training partner and I train at the same pace, we routinely use this approach in our interval workouts.
I'll use my current mile goal pace as an example. You will obviously be much faster, but this is just to illustrate the math.
1. Determine your desired training pace. Example: In my case, it's a 7:00 minute mile or 420 seconds/mile
2. Divide by 4 to get seconds/lap. (Yeah, I know that we're now working with 1600m and not 1609m, but it's close enough.) In my case 420/4 = 105 seconds/lap.
3. Divide seconds/lap by the number of cones you want to use. To keep it easy to set up, I put one cone every 50m around the track so that's 8 cones. 105 divided by 8 = 13 1/8.
4. I set the GymBoss to beep every 13 seconds. Or, I could download a Tabata app and set it to beep every 13 seconds. SmartWOD is good app for this on Android phones.
5. Every 50m cone, I get an audible beep to let me know if I'm a little too fast or a little too slow. A pacing check every 50m is good enough for me. If I wanted more pacing checks per lap, I'd add more cones and make the distance between them shorter.
Example for a 5 minute/mile pace
5min=300 sec or about 75sec/lap
* A cone every 50m is 8 cones. 8 into 75 seconds is 9 3/8 seconds. Oops. We can't set the GymBoss or the Tabata app in fractions of a second. A quick workaround is to divide the lap time by whole numbers until you get something very close to 75 seconds. After dividing 75 by a few numbers on either side of 8, we see that 11 almost works, so we'll use 11 cones over 400m. That's one cone every 36m. Set the interval timer at 7 seconds, so your timer will be pacing you at 77sec over the 400m. If that's not close enough to 75 for you, then just pace yourself to be 2 seconds ahead of the beep at the end of the lap.
Oh, one final point: wearable pacing devices are banned in USATF competition.