Roel Arits

I don't have a lot of free time to spend, but when i have a few hours, i will give it a go.Best regards,Roel.

Where do you live ? I ask because in the US f.e. the 2Nxxxx transistor types are more common then the BCxxx that i use a lot because they come from Philips Europe.

Hi Steve, Well, i learned the most by trial and error and by trying to understand existing circuits of other designers using books, magazines, service manuals, internet. This gives you both insight in how components/circuits work and also shows you different approaches to solve the same problem. You learn that there are many ways that lead to Rome. Selecting the way you want to go depends on cost, complexity, how accurate, how flexible a circuits needs to be. If i think about timing or generating delays, i think of the 555 timer chip. This chip is an old and very flexible workhorse that was first produced in 1972 and is still used a lot. The timer can be configured as a continuous running timer, but also as a one-shot (monostable multivibrator) by adding resistors and capacitors. But we…

Hi Steve, Well, i learned the most by trial and error and by trying to understand existing circuits of other designers using books, magazines, service manuals, internet. This gives you both insight in how components/circuits work and also shows you different approaches to solve the same problem. You learn that there are many ways that lead to Rome. Selecting the way you want to go depends on cost, complexity, how accurate, how flexible a circuits needs to be. If i think about timing or generating delays, i think of the 555 timer chip. This chip is an old and very flexible workhorse that was first produced in 1972 and is still used a lot. The timer can be configured as a continuous running timer, but also as a one-shot (monostable multivibrator) by adding resistors and capacitors. But we want the circuit to run from 3V, and that poses a problem : the power supply range of the 555 is 4.5V to 15V, so it can not run from 2x AA batteries. But there is a CMOS version of this chip, namely LMC555, that runs from power supplies down to 1.5V. So that is a candidate. Next we check the application notes for the chip to see how to configure it as a one-shot: when the circuits gets powered, it has to wait for a while before the output becomes high. The next thing to solve is : how to control the motor. The LMC555 output can not drive a motor directly, since it can deliver max. 100mA, which is not enough to drive a DC motor under load. So we need a power transistor that is able to deliver that current. This is the kind of think process that i would follow for a better circuit that is more flexible and not too complex. An Arduino is of course also a solution, and a solution that a lot of hobbyist would choose, because of the low cost and it doesn't require much knowledge of analog electronics. But to me an Arduino is overkill for such a simple task. It is almost an insult to the microcontroller to have it control just 1 pin to generate a delay. :-) But that is because i like to work with analog electronics that can also be build be hobbyists that are not into programming in C.Another route i would try to to use the same circuit, but then with a P-MOSFET with a very low gate threshold voltage (as low as 1V). The problem with that route is that these kinds of MOSFETs are harder to find/obtain. That makes this route less attractive for hobbyists because these components will not be found in electronics web-shops.So i think i would go for the LMC555 having some experience with designing analogue electronics. Otherwise an Arduino Pro Mini would be the next choice, because it's cheap and you don't need experience with analogue electronics. You can drive the motor via a relay module (incorporating the relay driver). Otherwise you will still need a power transistor (with a maximum collector current of lets day 1A) to drive the motor directly.I hope this helps a bit.Cheers,Roel.

About the 3 connections of R1: You can use 2 connections only, namely the wiper (middle) and one of the outer connections. It does not matter whether you use all 3 connections or just 2. About the slow motor : I started with 2x AA batteries as is stated in the schematics, but afterwards i changed to 3x AA batteries as you can see in the pictures because i wanted the motor to run a bit faster. The reason for the lower speed (when compared with just connecting the 2x AA directly to the motor) is that the darlington transistor drops about 1V (collector to emitter voltage). This 1V drop is inherent to darlington transistors and can not be changed. This makes the motor run a bit slower than without the circuit installed.I wanted to keep the electronics as simple as possible and using easy obta…

About the 3 connections of R1: You can use 2 connections only, namely the wiper (middle) and one of the outer connections. It does not matter whether you use all 3 connections or just 2. About the slow motor : I started with 2x AA batteries as is stated in the schematics, but afterwards i changed to 3x AA batteries as you can see in the pictures because i wanted the motor to run a bit faster. The reason for the lower speed (when compared with just connecting the 2x AA directly to the motor) is that the darlington transistor drops about 1V (collector to emitter voltage). This 1V drop is inherent to darlington transistors and can not be changed. This makes the motor run a bit slower than without the circuit installed.I wanted to keep the electronics as simple as possible and using easy obtainable parts. There are better solutions to create a delay, but then you need more components.Simple circuits always have drawbacks and compromises ... but they are easy to make. :-)

About the 3 connections of R1: You can use 2 connections only, namely the wiper (middle) and one of the outer connections. It does not matter whether you use all 3 connections or just 2.About the slow motor : I started with 2x AA batteries as is stated in the schematics, but afterwards i changed to 3x AA batteries as you can see in the pictures because i wanted the motor to run a bit faster. The reason for the lower speed (when compared with just connecting the 2x AA directly to the motor) is that the darlington transistor drops about 1V (collector to emitter voltage). This 1V drop is inherent to darlington transistors and can not be changed. This makes the motor run a bit slower than without the circuit installed.I wanted to keep the electronics as simple as possible and using easy obtai…

About the 3 connections of R1: You can use 2 connections only, namely the wiper (middle) and one of the outer connections. It does not matter whether you use all 3 connections or just 2.About the slow motor : I started with 2x AA batteries as is stated in the schematics, but afterwards i changed to 3x AA batteries as you can see in the pictures because i wanted the motor to run a bit faster. The reason for the lower speed (when compared with just connecting the 2x AA directly to the motor) is that the darlington transistor drops about 1V (collector to emitter voltage). This 1V drop is inherent to darlington transistors and can not be changed. This makes the motor run a bit slower than without the circuit installed.I wanted to keep the electronics as simple as possible and using easy obtainable parts. There are better solutions to create a delay, but then you need more components.Simple circuits always have drawbacks and compromises ... but they are easy to make. :-)

Hi derfaq. Thanks for the feedback. I'm glad your version with the 8 LEDs worked out well for you without having to rework the code. When i was experimenting with the software i also played with the thought to improve the way the acceleration is derived from the angle (inclination). I think you can indeed get a better result when using the acceleration vectors of the chip itself, because that is a more natural way to do this. Well there sure is room for improvement, so i'd say : have fun and experiment, because that is how i started this project. Maybe you can optimize and improve it further. Greetings, Roel

Thank you for the nice compliment !

The current source use in the instructable has an exponential behaviour to compensate for the logarithmic perception or our eyes. When you use the triangular waveform to control the LEDs, the brightness of the LEDs will not fade in a linear wayAn LM317 can be used as a fixed constant current source by using its internal reference voltage of 1.25V, but i don't see how you would turn the LM317 into a variable current source in combination with the triangular waveform generator output.You could simply connect an NPN medium power transistor configured as an emitter follower to the output of the triangular waveform generator so you have a higher output power to drive LEDs directly.https://electronics.stackexchange.com/questions/251111/emitter-follower-led-circuit-led-in-collector-resistor-in…

The current source use in the instructable has an exponential behaviour to compensate for the logarithmic perception or our eyes. When you use the triangular waveform to control the LEDs, the brightness of the LEDs will not fade in a linear wayAn LM317 can be used as a fixed constant current source by using its internal reference voltage of 1.25V, but i don't see how you would turn the LM317 into a variable current source in combination with the triangular waveform generator output.You could simply connect an NPN medium power transistor configured as an emitter follower to the output of the triangular waveform generator so you have a higher output power to drive LEDs directly.https://electronics.stackexchange.com/questions/251111/emitter-follower-led-circuit-led-in-collector-resistor-in-emitterThe next problem will be that the triangular waveform generator output does not swing from rail to rail. That means that the output does not go down to 0 volts, So if you want the LEDs to go off completely, you will need to bring the output voltage down with a couple of diodes in series or a zener diode.

Thanks kebmoore,RGB LEDs through white glass will also give a nice effect though. I tried that with "milky" white glass because that diffuses the light properly. But like you wrote : when the LEDs are off, you only see a white surface. On the other hand, that could be nice for a table or a surface where you don't expect that it suddenly gets coloured by RGB LEDs. F.e. : http://www.jimonlight.com/2009/06/15/64-rgb-led-ta...Cheers.